Hewlett-Packard Series 200, 400, and 600 Routers HP Routing Services and Applications...
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Contents Product Notes Features of HP Routers ......Architecture and Technology ..... . 1-21 Branch Office Routing .
Product Notes Features of HP Routers Architecture and Technology Branch Office Routing...
400 series have a fixed selection of ports, and routers in the 200 series have a partial selection of routing services. And for a central site router, the HP Router 650, port modules allow you to select the types and number of port connections needed.
Features of HP Routers Routing Services and Protocols router, a DECnet router, a bridge, and so on, when the associated service is enabled. On HP routers, routing services should be used when possible for their band- width-conserving value, and they must be used for links between dissimilar physical-layer and data-link-layer operations.
Features of HP Routers Routing Services and Protocols N o t e s However, HP routers do not transparently bridge from a token ring to a token ring (only between Ethernet/802.3 LANs); source-routing bridging is used for this function. Also note that the source-routing bridging func- tion does not provide communication between a source-routing system on one ring and a non-source-routing system on another ring.
Features of HP Routers Routing Services and Protocols incremental routing updates, and supporting a hierarchical update structure (using areas). RIP and OSPF are described in more detail in the “Internet Protocol Routing Service” note later in this manual. For connections to external IP networks, HP routers support the standard Exterior Gateway Protocol (EGP).
Features of HP Routers Routing Services and Protocols HP routers support AppleTalk Phase 2 routing over Ethernet links or synchronous WAN links. LocalTalk links to HP routers are not available. AppleTalk Phase 1 routing is not supported; however, it can be relayed using the bridging function of the router.
Features of HP Routers Security and Traffic Filtering Table 1. Routing Service Protocols on HP Routers Routing Service Network-Layer Network-Layer Data-Link-Layer (“Routable” Communication Routing Address Translation Protocol Protocol) Protocol Protocol (to get station address of node) AppleTalk Phase 2 AppleTalk Data- Routing Table Maintenance Protocol AppleTalk Address Resolution routing...
Features of HP Routers AdvanceStack Router Hardware AdvanceStack Router Hardware Series 600: Modular Routers The HP Router 650 is used as a high-speed central-site router. It is a compact table or rack-mountable chassis with four slots for LAN and/or WAN inter- face card modules.
Features of HP Routers LAN Media Connections LAN Media Connections The following types of ports are available on HP routers. See the HP Network Connectivity Product Catalog for the specific routers and their port combinations. Ethernet Ports Ethernet/IEEE 802.3 LAN ports use the following types of connectors: Twisted-pair RJ-45 connector, for IEEE 802.3 Type 10Base-T unshielded twisted-pair cable BNC connector, for a IEEE 802.3 Type 10Base2 thin coaxial cable...
Features of HP Routers WAN Connections and Services FDDI Ports An FDDI port is used to connect an FDDI ring to the router using a class A dual attachment station (DAS) or class B single attachment station (SAS) or dual homing. An optical bypass switch can be connected between the router and the DAS or SAS.
Features of HP Routers WAN Connections and Services WAN Ports On the synchronous ports, wide area network connections are established by connecting WAN-link-terminating equipment. This equipment, which provides timing signals to the router’s WAN interface, may be typically a data service unit/channel service unit (DSU/CSU), a modem, or an ISDN terminal adapter (using the V.25 bis standard protocol).
Features of HP Routers WAN Connections and Services Other WAN Services HP routers can use a proprietary point-to-point WAN protocol between themselves. Or, for interoperation in multivendor environ- ments, the industry-standard Point-to-Point Protocol (PPP) can be used. Dynamic link configuration allows bridging to be enabled automatically over leased lines, using the HP-proprietary protocol, between two HP routers or between an HP Remote Bridge and an HP router.
Features of HP Routers “Instant On” and SmartBoot “Instant On” and SmartBoot Implementing an internetwork with routers should not require that numerous network administrators be trained and staffed at every site in an organization. Ideally, routers should be installable and manageable by centralized MIS administrators remotely.
Features of HP Routers “Instant On” and SmartBoot Then, the router automatically acquires its configuration over the network, allowing it to perform routing. Two basic scenarios for this autoconfigura- tion over the network are the following. 1. The administrator of the router at the central/regional site has used Quick Remote—a component of SmartBoot included on HP routers—...
Features of HP Routers “Instant On” and SmartBoot Dynamic WAN Link Configuration HP routers auto-detect and negotiate the following when connected to an operational link: Device type of the HP router or HP Remote Bridge attached LLC protocol type (quality of service) Clocking and HDLC device address DCE or DTE Compression setting Link speed to automatically configure transmit queues...
Features of HP Routers Console (RS-232) Port Console (RS-232) Port The router has an RS-232 port specifically for out-of-band console access, using an ANSI or VT100 terminal or a PC running an ANSI or VT100 terminal emulation program, and optionally a modem. Information on terminals and modems and cables can be found in the installation manual for your router.
Features of HP Routers Console (RS-232) Port Configuration Routers are shipped from HP with a default configuration that allows them to come up in their attached networks as bridges. To perform routing with the various available protocols (such as IP, IPX), each interface will need at least some protocol- or network-specific configuration information.
Features of HP Routers Console (RS-232) Port Quick Remote Nearly every HP router includes an easy-to-use utility for automatically configuring the remote routers attached to its WAN ports. This is called Quick Remote. It is a simple screen that guides the network administrator at a central site to input and store the parameters minimally required to configure bridging, IP routing, and IPX routing on the HP routers attached on the point-to-point WAN links.
Features of HP Routers Network Management Network Management SNMP Management HP routers have a Simple Network Management Protocol (SNMP) agent, enabling them to be managed locally, using a console, or remotely, using a modem or Telnet (remote terminal access to console commands) or network management applications.
Architecture and Technology This product note describes the hardware and software architecture of the Router Series 200, 400, and 600. This note includes the features common to each series; technical data specific to each router is found in the Release Notes and Installation Guide for each series.
Architecture and Technology Series 200 and 400 Hardware Hardware Architecture Figure 1. Block Diagram of Series 200/400 Hardware Most of the series 200 and 400 routers use the Motorola 68020, 68EC020, or 68EC040 processors. The processor accesses three types of read-only memory (ROM) on the bus: This stores the router operating system code.
Architecture and Technology Router 650 Hardware Timer This generates interrupts and internal clocking for WAN ports. Console Port Controller National’s SONIC LAN and WAN Controller Coprocessors (Systems-Oriented Network Interface Controller) is a second-generation Ethernet controller that integrates a fully compatible 802.3 encoder and decoder.
Architecture and Technology Router 650 Hardware Routing Card Self-test R o u t i n g E n g i n e U t i l i z a t i o n Engine Card Self-test Fail Fail Fail Fail Card Self-test Fail...
Architecture and Technology Router 650 Hardware Multiprocessor and Memory Architecture The key feature of the HP Router 650 is its pipelined multiprocessor architecture. The routing engine uses the 33-megahertz Intel i960 CF RISC processor to handle network-layer protocol routing. Each interface card, here called a Data Link Accelerator (DLA) module, also uses a 33-megahertz Intel i960 CF RISC processor to offload the routing engine from the data-link- layer-specific tasks, such as header preprocessing, tabulating data-link-layer...
Architecture and Technology Router 650 Hardware The routing engine also has 128 kilobytes of high-speed cache to handle even a large number of end-to-end conversation streams, and eight megabytes of routing table memory (expandable by another eight to sixteen) to handle even the largest (1000 or more) router networks.
Architecture and Technology Router 650 Hardware Data Link Accelerator Architecture Figure 4. Block Diagram of Data Link Accelerator The Data Link Accelerators (interface cards) for the HP Router 650 use the 33-megahertz Intel i960 CF RISC processor. Data RAM Program variables and data critical to packet throughput (such as routing and bridging tables) are stored in a fast memory.
Architecture and Technology Router 650 Hardware Routing Engine Architecture Figure 5. Block Diagram of Routing Engine The routing engine PCA for the HP Router 650 uses the 33-mega- hertz Intel i960 CF RISC processor. Data RAM Program variables and data critical to packet throughput (such as routing and bridging tables) are stored in a fast memory.
Architecture and Technology Routing Software Technology Routing Software Technology A router is a layer three—network layer—device. Packets are routed using the network-layer addresses in the network protocol header of the packets. Each “routable” protocol suite, such as TCP/IP or Novell IPX (here called a routing service), manages its own forwarding based on its own address tables, routing protocols, and other routing configuration parameters as a separate software module.
Architecture and Technology Software Data Flow Architecture Software Data Flow Architecture The data flow, that is, the path taken by the packets, for the router software is shown in figure 6. It shows only the software modules critical to router throughput performance—those directly involved with routing or bridging packets through the router.
Architecture and Technology Software Data Flow Architecture Drivers A driver controls the data-link-layer (layer two) and physical-layer (layer one) protocols. The functions performed by a receiving driver include accepting packets from the network. The functions performed by a transmitting driver include accepting packets from the circuit group manager to forward onto the appropriate LAN or WAN link.
Architecture and Technology Software Control-Path Architecture Software Control-Path Architecture The flow of routing information used in selection of a route and network interface (circuit group) involves the routing protocols (RIP, ARP, OSPF, etc.) primarily. This flow is different for each bridging and routing service. For some services, the path can involve numerous choices of routing protocol and can involve other features as well, such as the import and export route filters for the IP routing service.
Architecture and Technology Software Control-Path Architecture Figure 8. Block Diagram of IPX Routing Information Flow 1-33...
Architecture and Technology Software Control-Path Architecture 1-34...
This note covers the issues related to the implementation of branch-office networks, and the steps Hewlett-Packard is taking to help customers build branch-office networks that meet business needs while minimizing costs.
Branch Office Routing Overview PC and workstation LANs are proliferating in branch offices for many reasons: to take advantage of low-cost PCs and new client-server applications; to share expensive peripheral devices; to customize applications to meet local needs; and to accommodate workgroup computing styles. This trend is forcing corporate network planners to consider solutions for linking the often large number of branch offices to the corporate informa- tion network.
Branch Office Routing Alternatively, many businesses, such as banking, financial services and insurance, require more than a single LAN at the remote office, as shown in figure 2. And there may be legacy devices there, such as IBM terminal controllers or automated teller machines using X.25 or SDLC, performing mission-critical functions, that must also be included in a particular branch networking solution.
Branch Office Routing Figure 2. High Complexity Branch Office Network Controlling WAN Costs WAN communication charges are now and will continue to be the single greatest cost component in annual branch office networking budgets. Support for popular WAN protocols and features that improve WAN performance, add robustness, and eliminate the need for redundant links all play a significant role in reducing WAN communications costs.
Branch Office Routing Packet-by-Packet Compression Packet-by-packet compression (HP PPC) is an innovative HP data-link compression technology that improves throughput and can eliminate the need to add costly incremental bandwidth. Unlike other compression solutions, HP PPC was developed for use with multiprotocol data over all link types including leased lines, packet switching networks, and circuit switching networks.
Branch Office Routing Reducing Cost and Improving Robustness Bandwidth reservation works with traffic prioritization. Protocols or data can be prioritized, and during periods of peak WAN utilization, bandwidth can be reserved for each priority level. The goal is to ensure that the highest priority data receives enough bandwidth without starving applications transmitting lower priority data.
Branch Office Routing Planning & Controlling WAN Capacity Call Controls Dial-up connections are governed by “smart” connection controls to take maximum advantage of dial-up circuits. Call controls allow a network designer to configure a router with billing period information. This informa- tion is used to hold dial-up circuits open as long as possible when it can be done at no cost, for example, until the end of a three-minute initial billing period.
Branch Office Routing Planning & Controlling WAN Capacity All HP routers include a network traffic sampling capability called HP EASE. EASE stands for Embedded Advanced Sampling Environment. This sampling technology provides an in-depth, accurate representation of network traffic without additional special equipment or set up and with virtually no additional network overhead (less than 1/4 of 1%).
Branch Office Routing “Instant-On” Branch Office Router Installation Figure 3. Traffic volumes between remote sites over a specified time period. Controlling Administrative Costs Extending the corporate network to remote offices concerns many network managers who are worried about the supportability of a branch office network.
Branch Office Routing “Instant-On” Branch Office Router Installation Hardware Designed for Branch Offices Every HP router, from the HP Router ER to the recently announced HP Router 650, have the following features to enhance remote support: Software preloaded in flash EEPROM memory. No disks to get lost, misplaced, or fail.
Branch Office Routing “Instant-On” Branch Office Router Installation SmartBoot A companion feature introduced in the first half of 1994, SmartBoot, allows a branch office access router to automatically retrieve its routing configura- tion information after establishing a connection with a corporate or regional router.
Branch Office Routing A Broad Range of Cost-Effective Solutions Controlling and Protecting Equipment Investments Equipment cost is a major concern in the deploy-ment of branch office networks that may contain tens or hundreds of routers. Seemingly small differences in purchase price can represent large savings as networks grow. Warranty is another important source for reducing costs.
Branch Office Routing Warranty Warranty HP provides a full 3-year warranty on all router products–the longest warranty in the industry. Besides lowering equipment costs, this is also a statement about the quality of HP’s router products and their ability to perform year after year.
Branch Office Routing Future Directions 1-48...
Routing Services Notes...
Routing Services Notes Bridging Service Internet Protocol Routing Service Novell IPX Routing Service AppleTalk Phase 2 Routing Service DECnet Routing Service A Primer on HP Probe Data Compression for WAN Links...
Bridging Service The HP router can operate as a multiport bridge. The bridging service may be enabled independently of any of the routing services; if not enabled, then the router will discard packets with protocol types not enabled or supported (such as IBM SNA or DEC LAT).
Bridging Service Transparent Bridging Transparent Bridging Transparent bridges provide network interconnection and/or extension services to LANs that employ identical protocols at the data link and physical layers. Transparent bridges place no burden on end nodes; they take no part in the route discovery or selection process. From the point of view of an end node, it appears that all nodes are resident on a single extended network with each node identified by a unique MAC-level address.
Bridging Service Transparent Bridging If the bridge finds a match between the destination address and a address table entry, it compares the circuit group on which the frame was received with the circuit group associated with the table entry. Identical circuit groups indicate that the source and destination end nodes are located on the same physical network.
Bridging Service Transparent Bridging For example, in figure 1, the red and white LANs are connected by two routers serving as parallel bridges, bridge 1 and bridge 2. Consider the chain of events when end node J on the red LAN first sends a frame to end node K on the white LAN.
Bridging Service Transparent Bridging Next, end node K receives two copies of the frame originated by end node J. While the reception of duplicate frames by a node is not generally fatal, at best such duplication represents an inefficient use of available bandwidth. Of graver consequence is the effect of duplicate frames on bridge 1 and bridge 2.
Bridging Service Transparent Bridging After determining the identity of the root bridge, all other bridges calculate path costs, that is the cost of the path to the root bridge offered by each bridge port. Each bridge designates the port that offers the lowest-cost path to the root bridge as the root port.
Bridging Service Token Ring Solutions Token Ring Solutions HP router software provides support for IBM source-routing bridging. This makes many new routing and bridging solutions possible in token ring environments. This section examines these routing and bridging applications and explains concepts central to routing and bridging in a token ring environ- ment.
Bridging Service Token Ring Solutions The backbone ring (the building’s backbone network) is a 16-Mbit/s token ring, which is accessible from each floor. Application rings, installed on each floor, are 4-Mbit/s token rings. Computers are attached to the application rings. IBM source-routing bridges are used to connect the application rings to the backbone ring.
Bridging Service Token Ring Solutions Routing in Token Ring and Mixed-Media Environments The IP, IPX, XNS, and AppleTalk routing services provide support for networks containing source-routing bridges. Source-routing support has not been provided for DECnet. Therefore, the following discussion of routing applies only to IP, IPX, XNS, and AppleTalk.
Bridging Service Token Ring Solutions ROUTER ROUTER ROUTER Figure 4. Routing in a mixed-media environment permits communication between all systems. Bridging in Token Ring Environments The bridging service on the HP routers includes source-routing bridging. Source-routing bridging is used to connect token rings containing systems that communicate using non-routable protocols such as IBM 3270 or NetBIOS.
Bridging Service Token Ring Solutions Higher-Layer Entities (Bridge Managment, etc.) LLC Entity LLC Entity SR LOGIC TB LOGIC RII = 1 MAC Entity MAC Entity Figure 5. Architecture of the Source-Routing/Transparent (SRT) Bridge Figure 5 shows an architectural model of the SRT bridge. When the SRT bridge receives a frame, it examines the Routing Information Indicator (RII).
Bridging Service Token Ring Solutions Limitations An SRT bridge does not, however, provide communica- tion between a source-routing system on one ring and a non-source- routing system on another ring. There are some basic differences at the MAC layer between token ring/IEEE 802.5 and Ethernet.
Bridging Service Token Ring Solutions First, consider the network in figure 7. Assume station addresses are statically assigned. Assume system A’s station address is 080009000000H, and system B’s station address is 010000000000. Each address is an individual address on its associated LAN. When packets are transmitted, the first part of the MAC header transmitted is the destination station address.
Bridging Service Token Ring Solutions Figure 8 shows the sequence of packets sent when system A (from figure 7) tries to determine the station address of system B using ARP, and then sends a data packet to B. First, system A broadcasts an ARP request, which the SRT bridge forwards onto the token ring.
Bridging Service Token Ring Solutions DEC Terminal Server ROUTER ROUTER Figure 9. Tunneling Used to Connect DEC VAXes Through a Token Ring Backbone Tunneling is a feature of the bridgingservice. It is not specifically enabled or configured. Instead, when the bridging software recognizes that an Ethernet packet is being transmitted onto a token ring network, the bridged packet is encapsulated for transmission to another HP router.
Bridging Service Token Ring Solutions Tunneling Direction: Ethernet Token Ring Ethernet SRT bridge tunnel packet: Tunnel Header Ethernet Header Data Tunnel Header: Destination Station Address (48 bits): Destination SRT Bridge * Source Station Address (48 bits): Source SRT Bridge DSAP (8 bits): AA (SNAP) SSAP (8 bits): AA (SNAP)
Bridging Service Source-Routing Bridging Source-Routing Bridging The term source routing was coined by IBM to describe a method of bridging frames across token ring networks. Source-routing bridges differ from transparent bridges in two critical ways: Source-routing bridges tolerate a multiplicity of paths between any two nodes in the extended network;...
Bridging Service Source-Routing Bridging After adding a routing designator, each bridge forwards the frame onto all ports except the port on which the frame was received. As a consequence, multiple copies of the same ARE frame can appear on a LAN, and the frame recipient can receive multiple copies of the frame (one copy for each possible path through the extended net- work).
Bridging Service Source-Routing Bridging How Source Routing Works Source routing networks consist of LAN segments interconnected by source routing bridges. Each LAN segment has an identification number unique throughout the network, called a LAN ID, and also called a ring number or ring ID.
Bridging Service Source-Routing Bridging Incoming Path Outgoing Path Internal Path 5 – Identifies the incoming LAN segment 1 – Identifies the source-routing bridge A– Identifies the internal virtual LAN 1 – Identifies the source-routing bridge 8 – Identifies the outgoing LAN segment 0 –...
Bridging Service Source-Routing Bridging Figure 13. Multi-Source-Routed Network In figure 13, router A is the first source-routing bridge to receive the ARE frame originated by H1. A inserts its routing designators (1–1, 7–1, 5–0) in the frame’s MAC header: MAC Header 1–1, 7–1, 5–0 All Routes Explorer (ARE) Frame Routing Designators...
Bridging Service Source-Routing Bridging Incoming Path 1–1 1 – identifies the incoming LAN segment (token ring 1) 1 – identifies bridge A Figure 14. Routing Designator 1 Internal Path 7–1 7 – identifies the internal virtual LAN segment 1 – identifies bridge A Figure 15.
Bridging Service Source-Routing Bridging Outgoing Path 5–0 5 – identifies the outging LAN segment (sync line 5) The bridge number in the last designator is always set to 0. Figure 16. Routing Designator 3 Router B (in figure 13) is the next source-routing bridge to receive the frame. B updates A’s last routing designator by changing bridge ID 0 to 1, and then inserts the remainder of its routing designators (8–1, 6–0) in the frame’s MAC header.
Bridging Service Source-Routing Bridging Router C (in figure 13) is the last source-routing bridge to receive the ARE frame. C updates B’s last routing designator by changing bridge ID 0 to 1, and then inserting the remainder of its routing designators (9–1, 2–0) in the frame’s MAC header.
Bridging Service Source-Routing Bridging Source-Routing Bridging on HP Routers This section describes the routing of frames through a network using HP’s source-routing architecture. The HP router configured as a source-routing bridge handles incoming packets differently depending on its position in the network.
Bridging Service Source-Routing Bridging Track 1. An Explorer Frame From Node 1 to Node 2 This section tracks explorer frames (AREs) sent from H1 to H2 in the sample HP source-routing bridging network. Figure 18 below illustrates the same network as does figure 17, except that arrows in figure 18 indicate the direction of the frame’s path.
Bridging Service Source-Routing Bridging Destination node station address Source node station address Routing control field Data 8270 DSAP SSAP Data Frame received by bridge A Incoming LAN ID; bridge ID Internal LAN ID; bridge ID Outgoing LAN ID; bridge ID of 0 8830 001A 100A...
Bridging Service Source-Routing Bridging Track 2. The Specifically Routed Frame Back to Node 1 This section tracks specifically routed frames (SRFs) sent back from H2 to H1. See figure 20. If there is only a single bridge ID (for an HP router) in the RIF, then the bridge simply transmits the frame to the outgoing circuit group without making any modification.
Bridging Service Source-Routing Bridging Between the first and last bridge receiving the SRF: The frame received by bridge B from ring 3 has traversed at least one other bridge. However, this is not the last bridge that the frame must traverse. This bridge does the following to the RIF before transmitting the frame to- ward ring 2.
Bridging Service Source-Routing Bridging Outgoing LAN ID; bridge ID Internal LAN ID; bridge ID Incoming LAN ID; bridge ID of 0 0CB0 001A 002A 003A 102A 0040 DSAP SSAP Data Frame received by bridge C HP group address Next bridge ID Group LAN ID Copy of destination station address C000A2FFFFFA...
Bridging Service Source-Routing Bridging Track 3. A Specifically Routed Frame From Node 1 to Node 2 This section tracks specifically routed frames (SRFs) from H1 to H2. HP’s source routing algorithm works the same as when H2 routes a specifically routed frame to H1.
Bridging Service Source-Routing Bridging Between the first and last bridge receiving the SRF: The next bridge B does the following to the RIF before transmitting the frame toward ring 3. (See figure 23.) Locates the bridge ID that is located at the end of the HP group address.
Bridging Service Source-Routing Bridging Incoming LAN ID; bridge ID Internal LAN ID; bridge ID Outgoing LAN ID; bridge ID of 0 0C30 001A 100A 002A 003A 0040 DSAP SSAP Data Frame received by bridge A HP group address Next bridge ID Group LAN ID Copy of dest.
Bridging Service Source-Routing Bridging Source-Routing/Transparent Bridging The SRT bridging provides concurrent transparent and source-routing services. Figure 24 shows a sample multi-ring, multi-Ethernet extended network linked by four routers serving as SRT bridges. Router T provides only transparent bridging services. The three other routers (all labeled S) provide both source-routing and transparent bridging services, when they have source routing enabled.
Bridging Service Source-Routing Bridging Source Route Translational Bridging (TRNSB) Source Route Translational Bridging (TRNSB) translates frames between source-routing bridging (SRB) circuit groups and transparent bridging (TB) circuit groups. The router translates frames for protocols such as SNA or NetBEUI between token ring circuit groups configured for SRB and Ethernet circuit groups configured for TB.
Bridging Service Source-Routing Bridging Site 1 Site 2 Ethernet Transparent Token HP Router HP Router Ring Server Client Figure 26. Transparent WAN Backbone Topology Figure 26 illustrates a common WAN topology that can use TRNSB. In this case, the primary bridging technology is transparent bridging. Thus, the WAN circuit group is not configured for source-routing bridging.
Bridging Service Source-Routing Bridging Transparent Backbone HP Router Token HP Router Ring HP Router Figure 28. Transparent Meshed WAN Backbone Topology Finally, figure 28 shows how TRNSB could be used in a meshed and transpar- ently bridged WAN backbone. To the TRNSB, this topology is really not different from that of figure 26.
Bridging Service Source-Routing Bridging There are two basic functions of the TRNSB, frame format conversion and bridge technology conversion, as detailed below. Frame Conversion Frame format conversion is merely moving the fields of the Medium Access Control (MAC) layer headers, or creating or deleting them. Figures 29 and 30 show the frame format conversions performed by the TRNSB.
Bridging Service Source-Routing Bridging Figure 30 shows conversion to the Ethernet version 2 frame format. (This is often called the PC/RT format, or 80D5 format.) The conversion is similar to that of figure 29. Bridge Technology Conversion From the perspective of the nodes on the Ethernet, the bridge technology conversion is an algorithm that makes it appear that all nodes on the token- ring SRB side are running on the same Ethernet LAN.
Bridging Service Source-Routing Bridging When the destination is not found in the address table or when the destination is a multicast address, the frame is converted to an explorer frame (single route explorer). This frame is then forwarded to all SRB circuit groups configured for TRNSB.
Bridging Service Source-Routing Bridging Configurable Hop-Count Reduction Algorithm In a source-routing bridging environment, a frame is generally limited to seven bridge hops. This standard source-routing algorithm counts one hop per intervening bridge and imposes a limit of seven hops from source- routing source to source-routing destination.
Bridging Service Source-Routing Bridging HP Router Bridge 1 Bridge 4 (Bridging) Internal LAN ID 3 End Node End Node Bridge ID 3 Figure 31. Sample Network for Hop Count Hop Count Reduction Algorithm Enabled In figure 31 (above), with Hop Count Reduction set to Yes, end node 1 sends an explorer frame.
Bridging Service Source-Routing Bridging The HP router receives this frame from ring 4 and learns that to get from the router to ring 5 through bridge 4, it needs to send the frame through ring 4. The router overwrites the internal LAN ID in the RIF with the outgoing ring that it learned when the frame first came through.
Bridging Service Source-Routing Bridging Configuring Source-Routing Bridging The parameters commonly used for configuring source routing globally for the bridging service include the following: Internal LAN ID Bridge ID Source Route Bridge ID Hop Count Reduction Group LAN ID Translational Bridge The parameters commonly used to configure source routing for each individual bridging circuit group include the following: Src Rte...
Bridging Service Source-Routing Bridging If two or more HP routers operate as bridges in parallel, then, to avoid loop- ing traffic, you must assign them different, unique bridge IDs. In this case, you must use the “Source Route Bridge ID” parameter to inform this bridg- ing router of each other HP bridging routers (that is, of the other bridge IDs) that exist on the network.
Bridging Service Source-Routing Bridging LAN ID A number unique throughout the internetwork is assigned to the Ethernet/802.3 LAN or token ring on each circuit group participating in source-routing bridging. The LAN ID is also known as a ring number or ring ID. Block Spanning Tree Explorer Frames Single-route explorer frames, also called spanning tree explorer (STE) frames or single-route...
Bridging Service Encapsulation Filters Encapsulation Filters Filters enable the bridge to either selectively relay or drop a particular frame on the basis of header fields used with each of the four encapsulation methods supported by the bridging service. These encapsulation methods are as follows: Ethernet IEEE 802.2 logical link control...
Bridging Service Encapsulation Filters DSAP SSAP Control Organization Prot. Type Data 1 octet 1 octet 1 octet 3 octets 2 octets Figure 35. SNAP Encapsulation SNAP encapsulation (shown in figure 35) is an extension of 802.2 encapsula- tion. It prefixes one octet of DSAP information, one octet of SSAP information, one octet of control information, three octets of organizational information, and two octets of upper-level protocol type information (some- times called Ethernet type) to the frame.
Bridging Service Encapsulation Filters Table 1 shows encapsulation support for each physical access medium: Table 1. Encapsulation/Media Matrix Medium Encapsulation Method Ethernet 802.2 SNAP Novell Ethernet/802.3 Token Ring FDDI Point-to-Point The bridge provides a set of pre-defined filter fields. Table 2 lists encapsulation methods along with associated pre-defined fields.
Bridging Service Traffic Filters Traffic Filters Traffic filters apply to all incoming bridge traffic across the circuit group. You can, if you wish, construct up to 31 filters for each bridging circuit group. Conceptually a filter consists of a rule which identifies packets to be filtered, an action to take upon receipt of a frame that meets the conditions of the rule, and a precedence that identifies which action to take in the event of a frame that meets the conditions of more than one rule.
Bridging Service Traffic Prioritization Traffic Prioritization Prioritizing Bridged Packet Traffic Router traffic, both bridged and routed, generally moves on a “first-in, first-out” basis. Prioritization can help to ensure that bridged packets that are sensitive to long response times (such as SNA packets) will not be delayed or dropped due to delays caused by traffic congestion.
Bridging Service Traffic Prioritization 2-54...
Internet Protocol Routing Service Routing consists of sending a packet from a source to a destination over one of several available paths. Unlike bridges, which must store routes to all hosts (end nodes) in an extended network, routers need only store routes to other networks, and to the end nodes in directly connected networks.
Internet Protocol Routing Service Applications of IP Applications of IP IP is the most widely implemented networking protocol, available on over 200 computer platforms. It supports the broadest set of application-level services, some of which are listed below. File transfer and distributed file systems: •...
IP addresses. Otherwise, you can build your own IP addressing scheme. Assigned Addresses Hewlett-Packard strongly recommends that if you intend to integrate your network with other IP networks or to expand your network in the future, you use assigned addresses. There is a formal process to obtain assigned unique IP addresses for networks worldwide.
Internet Protocol Routing Service IP Addressing Scheme Description An IP address consists of 32 bits divided into two or three fields: either network number and host number or else network number, subnet number, and host number. (An IP network generally comprises a single company or location.) The interconnection of IP networks is an internetwork.
Internet Protocol Routing Service IP Addressing Scheme After you have selected the address class and network number, the rest of the address bits are allocated to the host field or subdivided into subnet and host fields. The field lengths chosen for these fields will depend on how the network is subdivided.
Internet Protocol Routing Service IP Addressing Scheme Notation IP addresses are written in dotted decimal notation. Each decimal group (between the decimal points) is the decimal equivalent of 8 bits of the binary address. Notice that the dotted decimal divisions do not exactly correspond to the network, subnet, and host field divisions of the address.
Internet Protocol Routing Service IP Addressing Scheme Subnet Mask When assigning IP addresses, you will also assign subnet masks. A subnet mask tells you the total length chosen for the network and subnet fields. It is constructed as follows: 1. “1” is assigned to each network and subnet bit. 2.
Internet Protocol Routing Service IP Addressing Scheme Suggestion for Assigning Addresses Once your network number is assigned and you have selected the subnet mask, you have apportioned the address space that will be available for additional subnets and for additional hosts in the future. Because it may not be clear which will increase more—subnets or hosts—you can start with the scheme described below to reserve the most flexibility for expansion.
Internet Protocol Routing Service IP Addressing Scheme Example Topology Figure 2 shows an IP internetwork that connects subnetworks in five cities using HP routers, with IP routing service enabled, and an HP Remote Bridge RB. The network is an autonomous system with IP network address 188.8.131.52 and subnet mask 255.255.255.0.
Internet Protocol Routing Service IP Routing Decisions IP Routing Decisions IP routing decisions are based upon the destination network-layer address contained in each data packet that is traveling through the IP network. The most significant bits of the address identify the destination subnetwork, while the least significant bits identify a specific node (host, router, HP managed hub, HP managed bridge, etc.) on that subnetwork.
Internet Protocol Routing Service IP Routing Decisions IP Routing Table The IP routing table contains an entry for each subnetwork that the router has learned about. For each destination subnetwork entry, the table also contains the following information: Metric: the cost, typically in terms of “hop count”, to the destination subnetwork from this router.
Internet Protocol Routing Service IP Routing Decisions Routing Protocols Routing Information Protocol, RIP, is an interior gateway proto- col (IGP) for exchanging network reachability and routing information within an autonomous system. RIP is relatively simple to configure and is best suited for smaller networks (fewer than 15 hops in diameter), although it can be configured for a network diameter of up to 127 hops.
Internet Protocol Routing Service IP Routing Decisions OSPF enables you to configure variable-length subnet masks on different subnetworks, which can be used to conserve IP address space. OSPF enables you to configure a password so that all OSPF messages received will be authenticated for added network security.
Internet Protocol Routing Service The IP Network Interface Definition The IP Network Interface Definition The HP router must have an IP interface defined for each attached network using IP routing. On the HP routers, “circuit groups” connect the router to its networks.
Internet Protocol Routing Service Static Routing Static Routing The IP router provides the following types of static routing that can be used instead of dynamic routing, based on a packet’s destination address: Conditional and nonconditional static routes to specify a path to another router for a specific destination.
Internet Protocol Routing Service Static Routing Figure 4. Static Route Example 1 Default route example 1: When the HP router has a small number of directly connected networks and has a single connection to another router or router backbone, a default route can be configured to the other router.
Internet Protocol Routing Service Static Routing Figure 5. Default Route Example 1 Default route example 2: To connect an HP router to another network that uses a different interior gateway protocol (IGP), a default route is used. One such example, shown in figure 6, is connecting an HP router to a Cisco router backbone that uses IGRP, a proprietary routing protocol.
Internet Protocol Routing Service Static Routing IP traffic. RIP Supply, RIP Listen, Default Route Supply, and Default Route Listen will not be configured. In addition, for LANs and direct point-to-point connections, ARP or both ARP and HP Probe will be used for address resolution;...
Internet Protocol Routing Service Static Routing Conditional Static Route A static route can be configured as conditional on the status of a circuit group other than the one that directly accesses the next hop router. For example, consider figure 7. The frame relay subnet 11.1.8.x provides the primary routes.
Internet Protocol Routing Service Static Routing To achieve this effect, router C will be configured to advertise its ISDN route to D as lower in cost than the individual ISDN static routes from A and B to D. (Note that this ISDN route from C to D would be configured to be more costly than the WAN route when the WAN route to D is up.) The following table shows an example of how to configure the above solution for access to 10.4.8.x with and without a break in the WAN route to router D.
Internet Protocol Routing Service Static Routing By default, the IP router uses manually configured static and/or default routes in preference to routes gathered by protocol exchanges. You can configure the preference for each static (conditional or nonconditional) route as a weighted value used by the IP router to select from multiple routes to a single destination.
Internet Protocol Routing Service Static Routing Figure 8. Multiple Default Routes Adjacent Host Route Adjacent hosts are end nodes on a locally-attached network. Specify an adjacent host if you are setting up a network or if a particular local host or hosts don’t respond to ARP requests.
Internet Protocol Routing Service Static Routing Ethernet (the default) is the standard Ethernet 2.0 encapsulation for hosts that support Ethernet. This type is required for point-to-point or any type of X.25 interface.) If you are defining a LAN interface (Ethernet or IEEE 802.x), you must specify the encapsulation method supported by the attached network.
Internet Protocol Routing Service Static Routing SNAP (an extension of 802.2 encapsulation) can be used for hosts that support SNAP. The SNAP structure is encapsulated within a medium-specific 802.x packet. DSAP SSAP Organization Ether Type 1 octet 1 octet Control Data 3 octets 2 octets...
Internet Protocol Routing Service IP Filters IP Filters Routing Filters The HP routers support import and export route filters to allow you to modify the order of precedence for deriving routes to a given destination network. Import filters restrict the input of routing information about a given destination by a particular routing protocol.
Internet Protocol Routing Service IP Filters The relationship between the routing pool, forwarding tables, and the import and export rules is shown conceptually below. Import Rules Routing Pool Forwarding Export Rules Table Figure 12. Routing Information Data Flow for RIP Constructing RIP Import and Export Route Filters Each filtering rule must specify an incoming/originating routing pro- tocol.
Internet Protocol Routing Service IP Filters Packet Filters In addition to routing protocol filters, HP routers also support packet filters that can be used to secure the network or to control traffic flow. Packets can be forwarded, dropped, or passed to subsequent filters based the contents of specific fields within the IP packet, UDP packet, or TCP segment headers—...
Internet Protocol Routing Service IP Filters TCP and UDP Well-Known Port Numbers Port Protocol Usage Port Protocol Usage reserved – NAMESERVER TCP & UDP unassigned – NICNAME TCP & UDP unassigned – DOMAIN TCP & UDP unassigned – BOOTPS TCP & UDP unassigned –...
Internet Protocol Routing Service IP Filters Fields Operator Values Action Destination 192.32.165 Address Source 184.108.40.206 DROP Filter Rule A Address Port Number Fields Operator Values Action Destination 220.127.116.11 Address DROP Filter Rule B Source 18.104.22.168 Address Figure 13. Sample IP Filters IP Filter Lists Filter lists (while not required) may facilitate the configuration of filters if you wish the filter to apply to non-contiguous...
Internet Protocol Routing Service IP Filters User-Defined Fields in the Packet You can filter IP traffic based upon specified bit patterns contained within the IP header or the header of the upper-level protocol. User-defined field filters can be used by themselves or in conjunction with IP address and/or UDP/TCP port filters.
Internet Protocol Routing Service Device Management Functions Device Management Functions Ping (Packet InterNet Groper) tests reachability to IP devices using an ICMP echo request and reply sequence. ICMP, the Internet Control Message Protocol, handles IP error and control messages. Ping is used to verify and troubleshoot IP networks.
Internet Protocol Routing Service BootP and DHCP BootP and DHCP Bootp (Bootstrap Protocol) is a protocol that runs over UDP. It uses two UDP port numbers, 67 and 68. UDP port 67 specifies a Bootp server. UDP port 68 specifies a Bootp client. In operation, a client sends a Bootrequest to a server using a destination port of 67.
Internet Protocol Routing Service BootP and DHCP The relay agent sends the Bootrequest either to specifically configured addresses or to the broadcast IP address. When the Bootp server receives the relayed request, it sends the Bootreply to the relay agent that is adjacent to the client.
Internet Protocol Routing Service BootP and DHCP Figure 16. Bootrequest Relay with No Specific Server or Subnet The Bootp relay agent can be configured with a list of destination addresses for Bootrequest packets. An address on this list can be any one of three types, as follows.
Internet Protocol Routing Service BootP and DHCP All-Networks or All-Subnets Broadcast Address is 255.255.255.255, the default used when there are no addresses config- ured in the Bootrequest destination list. An all-subnets broadcast address has the network number followed by all zeroes or all ones. For example, a network 15 all-subnets broadcast is 22.214.171.124.
Internet Protocol Routing Service Virtual IP Host on Non-IP Networks Virtual IP Host on Non-IP Networks A router is often used in non-IP environments, for example, as a Novell IPX router or as a bridge. Sometimes in these environments it is desirable to have access to the router device management capabilities listed above, but without the burden of planning and configuring an IP routing network.
Internet Protocol Routing Service Virtual IP Host on Non-IP Networks Suppose that there are network-layer-transparent devices, such as repeaters or bridges, that support SNMP management on the LAN in Chicago. To access these devices from the router or the network management station, bridging and IP services would have to be enabled on router 2’s interface to that LAN.
Internet Protocol Routing Service Virtual IP Host on Non-IP Networks In host-only mode the HP router acts as an IP end node if bridging is not configured, or as a bridge if bridging is configured to a network management station. When using SNMP/IP-based HP Openview network management products, the router is not autodiscovered and displayed on maps as a router.
Internet Protocol Routing Service Source Routing and Token Ring Support Source Routing and Token Ring Support There are two ways traffic may communicate in an internetwork mixed with token ring/IEEE 802.5 and Ethernet/IEEE 802.3 networks. See the “Briding Service” note earlier in this manual for a detailed discussion of source routing and support for token ring LANs.
Internet Protocol Routing Service Specifications Specifications The specifications for the IP protocols are documented in a numbered series of technical reports called “Requests for Comments” or RFCs. The Internet Activities Board is the official committee for IP-related standards issued as RFCs.
Novell IPX Routing Service Novell NetWare LANs are generally PC and/or workstation environments. NetWare supports a wide variety of LAN topologies and media. The HP routers support the Novell Internetwork Packet Exchange (IPX) routing service and the Sequenced Packet Exchange (SPX) protocol. IPX is the network-layer communication protocol used by Novell NetWare.
Novell IPX Routing Service General Addressing Considerations Bindery Services: manage name resolution, accounting, and security. Diagnostic Services: retrieve software setup and status. Directory Services: access a distributed file system directory. File Services: access remote files. Message Services: deliver datagrams to IPX nodes. Message Handling Service (MHS): handle electronic mail file and exchange formats and procedures Queue Management Services (QMS): handle control queues of...
Novell IPX Routing Service General Addressing Considerations Control Destination Network Number Destination Network Destination Host Number Header Address Destination Socket Number Source Network Number Source Network Source Host Number Address Source Socket Number NetWare Core Protocol packet (0 to 546 octets) Data Figure 1.
Novell IPX Routing Service General Addressing Considerations IPX network numbers are 32-bit numbers (8 hexadecimal digits). On HP routers, a unique network number must be assigned to each network interface where IPX routing service will be enabled. Devices connected to the same network as a router interface must use the same network number that is configured on that router interface.
Novell IPX Routing Service Novell Data-Link Layer Encapsulation Figure 2. IPX Internetwork Novell Data-Link Layer Encapsulation In addition to Ethernet and IEEE 802.2 encapsulation for data-link-layer frames, IPX routing service supports the proprietary Novell encapsulation. Novell encapsulation, as shown below, prefixes an eight-octet preamble, six octets of destination-address information, six octets of source-address information, and two octets of packet-length information to the IPX packet.
Novell IPX Routing Service IPX Routing Table Length 2 octets Preamble Source Data Destination 8 octets 6 octets 6 octets 46–576 octets IPX Header NetWare Core Protocol Packet Figure 3. Novell Encapsulation The maximum length of an IPX packet passed through the router is 576 bytes.
Novell IPX Routing Service Routing Information Protocol Route Type specifies whether the destination network is remote or directly connected. Also, if the router is notified that a learned route is no longer available, then the route type is marked invalid. The route will remain in the table until the router is notified of another valid route to the destination or the router is rebooted.
Novell IPX Routing Service IPX Static Routes RIP requests and responses are sent as data in IPX packets. The Novell NetWare version of RIP uses IPX socket 453h. RIP imposes a network diameter limit of 15 hops or less on IPX internet- works.
Novell IPX Routing Service Service Advertising Protocol or changes a bindery entry and broadcasts service advertising packets to other networks. On HP routers, the SAP bindery (table) can be displayed using NCL’s Rgetis command. For more information on the IPX SAP table, refer to the operator’s guide for an HP router.
Novell IPX Routing Service NetBIOS Protocol Support NetBIOS Protocol Support The Network Basic Input/Output System (NetBIOS) is a widely implemented session-layer protocol developed by Sytek, Inc., for IBM PC networks. Many vendors have written programs that are compatible with NetBIOS. NetBIOS broadcasts are used by client programs to establish the connections with servers.
Novell IPX Routing Service NetBIOS Protocol Support NetBIOS Broadcast Static Routes HP routers provide a non-Novell-standard static-routing mechanism that converts IPX “all nets” NetBIOS broadcast packets to directed broadcast packets. A directed broadcast is an IPX network-level broadcast to a single network.
Novell IPX Routing Service NetBIOS Protocol Support 2-106...
AppleTalk Phase 2 Routing Service The HP routers support AppleTalk Phase 2 routing over Ethernet or token ring links and synchronous WAN links. AppleTalk Phase 1 routing is not supported; however, it can be relayed using the bridging service. More detailed information about AppleTalk Phase 2 can be found in the configuration guide for an HP router.
AppleTalk Phase 2 Routing Service Half router: Two routers, each connected to one or more AppleTalk LANs, and connected to each other through long-distance communi- cation links, are called half routers. Figure 2. Half Router Configuration Backbone router: Routers, each connected to one or more AppleTalk LANs, connected together through either an Ethernet backbone or an X.25 packet-switching backbone network, are called backbone routers.
AppleTalk Phase 2 Routing Service A sample network map for an AppleTalk internetwork is shown below in figure 4. Zone: Advertising Zone: Marketing Network 7-8 Network 4-5 Network 6-6 Network 2-2 Zone: Marketing Zone: R&D Network 9-11 Network 3-3 Zone: R&D S= Seed Network 1-1 Figure 4.
AppleTalk Phase 2 Routing Service Assigning AppleTalk Addresses Assigning AppleTalk Addresses In an AppleTalk internet, nodes (end systems or routers) and networks are assigned addresses. Nodes and routers are each assigned node addresses that are unique throughout the internet. The AppleTalk node address consists of: a 16-bit network number (1–65279) an 8-bit node identifier (1–253) Each end node is assigned to an AppleTalk network and has a unique node...
AppleTalk Phase 2 Routing Service Zones Zones AppleTalk nodes and networks are assigned zones in which they will reside. Zones are logical grouping of nodes that share the same network resources. Zones may encompass more than one network. Nodes in a zone need not be physically contiguous and need not have the same network number.
AppleTalk Phase 2 Routing Service Seed Routers Seed Routers A router identified as a seed router for a network has been configured with the network number range and default zone name for all the nodes that reside on the attached network. (Both the network number range and the default zone name can be configured using either Quick Configuration or the Configuration Editor.) At least one seed router, configured with the network number range and...
AppleTalk Phase 2 Routing Service AppleTalk Protocols AppleTalk Protocols The AppleTalk protocols provide network-access standards for layers one through five (in the Open Systems Interconnection (OSI) reference model). Protocols for layers two through five are shown in figure 5. AppleTalk Protocol Stack Corresponding OSI Protocol Layer Zone Information Protocol (ZIP)
AppleTalk Phase 2 Routing Service AppleTalk Protocols Datagram Delivery Protocol (DDP) Provides a “best-effort” socket-to-socket delivery of datagrams over an AppleTalk internet. Acquires the AppleTalk network number. Routing Table Maintenance Protocol (RTMP) Builds and maintains the AppleTalk routing table. Each table entry includes a destination network range, the AppleTalk node address (network number and node identifier) through which the destination is reached, the number of router hops to the destination, and the...
DECnet Routing Service The HP routers support DECnet Phase IV routing services. Unlike IP, IPX, AppleTalk, and XNS routing services, source-routing support is not provided for the DECnet routing service. The HP routers implement the DECnet routing protocol (DRP), the network-layer protocol of the Digital Network Architecture (DNA).
DECnet Routing Service DECnet Services DECnet Services The following are among the services available on a DECnet internetwork through HP routers: Virtual Terminal Service: allows a remote terminal to access a host system. (Also known as CTERM, control terminal module). Data Access Protocol (DAP): is a presentation-layer protocol suite that provides functions for exchanging data between two nodes on a network.
DECnet Routing Service General Addressing Considerations Dividing a DECnet internetwork into areas provides two advantages. First, it takes advantage of the entire range of network addresses available to you. Second, it improves the efficiency of your internetwork by reducing the volume of control messages.
DECnet Routing Service Station Address Resolution Station Address Resolution On each DECnet node, network-layer addresses are resolved to station (MAC) addresses when the node initializes. The station address on these nodes will be modified based on the area number and node number that you have configured on the nodes.
DECnet Routing Service DECnet Link Cost N o t e : When the DECnet routing service is enabled on HP routers, the station address will be modified, as described above, on all interfaces, even those where DECnet routing service is not enabled. This “DEC” station address will become the node ID for the router for IPX and XNS routing services.
DECnet Routing Service Designated Router Designated Router DECnet end nodes always reside on LANs, and each maintains an “on-Ethernet cache” of other nodes on its LAN. When an end node sends packets destined for a node on a remote LAN (a node that is not in the cache), the packets are sent to the “designated router”.
DECnet Routing Service Hierarchical Routing DECnet nodes establish adjacencies as part of their initialization sequence. End nodes multicast “Endnode Hello Messages” to establish adjacencies with routers on the same LAN. Routers multicast “Router Hello Messages” to establish adjacencies with one another and to elect the designated router. Additionally, the designated router multicasts “Router Hello Messages”...
DECnet Routing Service DECnet Routing Metric DECnet Routing Metric In both the level 1 and level 2 routing tables, the routing metric that is main- tained is (path) cost. Each DECnet LAN and WAN has a cost value associ- ated with it that relates to the speed of the link. Faster links have lower cost values associated with them.
DECnet Routing Service Routing Table Maintenance Routing Table Maintenance DECnet routers maintain their routing tables by multicasting routing messages to adjacent routers. A level 1 routing message is periodically multicast to adjacent routers in the same area. The level 1 routing message contains the sending router’s current information on the routes to all nodes in the area.
DECnet Routing Service DECnet Router Operations DECnet Router Operations Use the Network Control Language Interpreter (NCL) to display DECnet events, access DECnet statistics, view DECnet routing tables, and display DECnet management information base (MIB) variables. For detailed infor- mation on NCL and the various DECnet routing service operations, refer to the user’s guide and reference manual.
A Primer on HP Probe HP Probe is a Hewlett-Packard proprietary protocol used on HP nodes. It is an unreliable-connectionless request reply protocol designed to provide the name-to-address mapping information between HP nodes using Network Services (NS), and on HP Data Communications and Terminal Controllers (DTCs).
A Primer on HP Probe HP Probe Protocol Definition HP Probe Protocol Definition HP Probe supports both Ethernet and IEEE 802.3 encapsulation. HP Probe uses two multicast addresses: a primary multicast address 0x090009000001, and a secondary proxy multicast address 0x090009000002. Their use will be explained below.
A Primer on HP Probe HP Probe Protocol Definition over the secondary multicast address. See “Probe Proxy Request/Reply” below for more information. Node B responds to the name request with a path report that contains the IP and link-level station (MAC) addresses of the target node. The station address in the response received from the target node will only be consid- ered valid if the IP or network numbers are the same as the originator’s.
A Primer on HP Probe HP Router Probe Implementation HP Router Probe Implementation When HP routers boot, they transmit on all IP network interfaces the unsolicited reply announcing their presence. The routers use Probe VNA like ARP in order to obtain the station address of a destination node, and will try both Ethernet and IEEE 802.3 encapsulation to contact the target node.
A Primer on HP Probe Connection Scenarios Scenario 1 Figure 1 shows the first connection scenario, without a proxy server. Both routers are configured for IP routing and bridging Node A wants to set up a TCP connection to node B, which is on the other side of the network.
A Primer on HP Probe Connection Scenarios 1. Node A wants to connect to node B, checks the Nodal Registry, and does not have an entry for node B. It sends out a Probe name request. 2. The name request from node A is bridged by the routers to node B. 3.
A Primer on HP Probe Connection Scenarios 16. The local router receives the TCP ack sync packet for node A; if it is not in the ARP cache, it sends a VNA request (and ARP, if it is enabled) for node A’s station address. 17.
A Primer on HP Probe Summary Summary In order to run NS on an IP router network, the main issue is how the name- to-IP-address mapping is done for nodes on other subnets. If bridging is enabled, then the name requests are bridged and the mapping is performed using Probe name request/reply packets.
Data Compression for WAN Links What is Compression? Data Compression for WAN Links Using data compression on wide area links has ramifications that must be considered when implementing routed network solutions. This note will do the following: Describe current methods of data compression. Briefly explain HP’s compression algorithm.
Data Compression for WAN Links What is Compression? and receiving devices must have the same dictionary in order to replace the key with the original text at the receiving end. Running Dictionary One method of data compression uses a “running dictionary”, meaning that the mappings of strings to keys is maintained and reused across multiple packets being transmitted and received.
Data Compression for WAN Links HP’s Compression Algorithm HP’s Compression Algorithm Beginning November 1, 1993, HP has been shipping a variation of the Lempel- Ziv (LZ) lossless compression algorithm on all HP routers. The HP scheme (called HP Packet-by-Packet Compression, or HP PPC) compresses each packet independently using the packet-by-packet dictionary method in which the dictionary is reset with each packet.
Data Compression for WAN Links Compression Performance Testing Compression Performance Testing HP conducted performance testing using the Calgary Corpus test files, which are industry-standard files for performance testing using various types of data. The table below describes each file in the Calgary Corpus set. File name File Description File Size (bytes)
Data Compression for WAN Links Test Results Using these test files, HP routers were set up in various configurations and file transfers were done across HP point-to-point links to determine accept- able performance and throughput. Tests were conducted using both IP and IPX protocols.
Data Compression for WAN Links Design Guidelines Each 4-port synchronous interface card has an aggregate throughput of 306 Kbit/s to 460 Kbit/s with compression running. The Router 650 is designed such that each interface card has its own processor, so all compression processing is done on the interface card.
Data Compression for WAN Links WAN link planning WAN link planning When planning a wide area network, it may be useful to know what link speeds are needed given an estimated WAN utilization level. For example, if you know you will utilize approximately 84 Kbit/s of WAN bandwidth, then what link speed should you purchase for running compression? You can use the following formula to determine the desired link speed: (throughput) / 1.5 = (link speed)
Data Compression for WAN Links WAN link planning 3. For all HP routers: When running slow WAN links (9.6 Kbit/s to 19.2 Kbit/s) it is usually beneficial to run compression. Throughput will generally be improved when running compression on very slow links, so it is a good idea to turn on compression for these links except where noted below.
Data Compression for WAN Links Conclusion Versions of PBURST.NLM earlier than 2.02 had problems that also led to insufficient performance in both compression and non- compression environments. It is therefore recommended that version 2.02 or later be used. Similar reasoning is used in the VLM 1.1 client software recommendation.
Data Compression for WAN Links Conclusion 2-142...
Application Notes and Case Studies...
Application Notes and Case Studies Improving Network Availability ISDN Wide Area Network Design: Dry Creek Joint Elementary School District Shining a Light on FDDI Using Synchronous Pass-Through to Consolidate Synchronous Traffic Routing with OSPF Linking Up withFrame Relay Frame Relay Network Design: Fleet Call, Inc.,...
Improving Network Availability Updated 7/93 For companies that rely heavily on network applications, a failure in the network can be disastrous. Network failures are more likely to occur as networks grow—the natural result of employing more and more network equipment. This application note examines some of the methods for increasing network availability (uptime) in router-based networks and thereby reducing or eliminating user-perceived network failures.
Improving Network Availability Permanent Alternate Paths SITE B Link 2 Link 1 SITE A SITE C Figure 1. Improving Availability with an Alternate Path Data is routed between any two networks on the lowest-cost path. The lowest-cost path from a router to a destination network is determined by the router’s redirectors.
Improving Network Availability Coterminus Circuits setup delays or other problems that can occur with switched backup schemes. Flexible networking options. Although the permanent alternate path selected for wide-area networks is typically a leased line, it could be a public switched service such as X.25, frame relay, or SMDS. In addition, there is a wide range of link speeds from which to choose.
Improving Network Availability Circuit Group Manager If one circuit fails, traffic is carried on the remaining circuit(s). As long as one circuit within a circuit group is functioning, the redirectors are not informed of circuit failures and thus do not try to find an alternate route. When the failed circuit is restored, it will automatically be used for sending traffic to the remote router.
Improving Network Availability Circuit Group Manager Table 1. Packet Types for Random Circuit Assignment Protocol Packet Type AppleTalk Zone Information Protocol (ZIP) AppleTalk Routing Table Maintenance Protocol (RTMP) AppleTalk Name Binding Protocol (NBP) AppleTalk Address Resolution Protocol (AARP) AppleTalk Echo Protocol (AEP) DECnet Routing Protocol Learning Bridge...
Improving Network Availability Load Balancing Overrides Table 2 shows the packet types for which the indexed circuit assignment algorithm is used. Also shown is the index used for the calculation. Table 2. Packet Types for Indexed Circuit Assignment Protocol Packet Type Index AppleTalk data packets...
Improving Network Availability Load Balancing Limitations Load Balancing Limitations First, the circuit assignment algorithms ignore such obvious parameters as delay and throughput. This means that circuits placed in a circuit group must be of the same capacity. Otherwise, low-capacity circuits (56 Kbit/s) will have to handle the same networking load as high- capacity circuits (1.544 Mbit/s).
Improving Network Availability Circuit-Switching Networks Public Packet-Switching Network Inter-switch trunks Switching nodes Figure 3. LANs Connected through a Packet-Switching Network Although packet-switching networks are themselves typically highly reliable, the access circuit that attaches a router to the network is subject to failure and thus is an obvious point of vulnerability.
Improving Network Availability Circuit Group Considerations Circuit switching is a fundamentally different concept from packet switching. In a circuit-switching network the subscribers or users must dial a phone number to access a remote device such as a router. When the number is dialed, a data path is established by the circuit-switching network.
Improving Network Availability Circuit Group Considerations CIRCUIT SWITCHING NETWORK Figure 4. Routing Using Switched Network Services Backup Circuits Switched circuits are often the most cost-effective alternative to a meshed network (a network using permanent alternate paths) for improving availability. Switched services may be used to back up private leased lines or packet-switching networks.
Improving Network Availability Circuit Group Considerations A backup circuit is defined when the circuit is added to a circuit group as a “backup circuit group member”. Figure 5 shows a circuit group with a primary and a backup circuit. A backup circuit is enabled when the primary circuit(s) in a circuit group fails.
Improving Network Availability Circuit Group Considerations Circuit Group To Switched Terminal Network Adapter Terminal To Switched Adapter Network Termnial To Switched Adapter Network Pool Circuits Figure 6. Pool Members of a Circuit Group The use of pool circuits is ideal in a couple of situations. The first situation is when the traffic volumes are low and transmissions are infrequent.
Improving Network Availability Circuit Group Considerations Circuit Switching Network Figure 7. Leased-Line Network with Circuit-Switching Backup Packet Switching Network Circuit Switching Network Figure 8. Packet-Switching Network with Circuit-Switching Backup 3-15...
Improving Network Availability Switched Circuit Types Minimizing Connect-Time Costs One of the most important issues with circuit switching is minimizing the cost of connect time. Several connection controls have been provided to manage the opening and closing of connections to avoid connection charges. These controls are described later in this document.
Improving Network Availability Switched Circuit Types Manual Adapter A manual adapter refers to any DCE (ISDN terminal adapter, modem, or DSU/CSU) that will initiate a connection to a remote DCE when the router raises the DTR lead (the data-terminal-ready signal) on the interface to the DCE.
Improving Network Availability Switched Circuit Types ISDN Network Events ready to receive call data rec’d call TA "B" *** Connection Established *** Figure 9. Connection Sequence for Manual Adapters Figure 9 shows the events in the connection sequence for two routers using manual adapters.
Improving Network Availability Switched Circuit Types Connection Controls—Manual Adapter Using the connection method discussed in the previous section, several connection control parameters are useful in situations in which the destination is busy and in which connections fail due to problems in the network itself.
Improving Network Availability Switched Circuit Types V.25 bis Adapter V.25 bis is a CCITT data-communications standard that defines a set of commands exchanged between a DTE and a DCE. These commands control setting up and tearing down switched communications services. V.25 bis is similar in concept to the Hayes AT command set used in PC-to-modem communications.
Improving Network Availability Switched Circuit Types ISDN Network Events data rec’d call TA "B" call from "A" rec’d *** Connection Established *** Data Transmitted Figure 10. Connection Sequence for V.25 bis Figure 10 shows the sequence of events in a successfully initiated connection between routers using V.25 bis terminal adapters.
Improving Network Availability Switched Circuit Types router will not accept the call (based on configured call restrictions), it immediately drops DTR. Otherwise the adapter subsequently drops CTS. As soon as the switched circuit is complete, DSR (data set ready) is raised by each adapter and the circuit is established.
Improving Network Availability Sample Networks Sample Networks The following sections show some of the applications for switched circuits and the methods for using circuit-switching networks on HP routers. Low-Volume, Infrequent Transmissions Figure 11 shows a network in which the traffic volumes are low and transmissions are infrequent.
Improving Network Availability Sample Networks Alternatively, the central-site switched circuits may be configured with individual phone numbers. Remote sites (under V.25 bis control) would then have several possible numbers to dial to get around busy conditions. Switched-circuit-only networks can be a very cost-effective alternative when used for several hours or less each day.
Improving Network Availability Sample Networks Dedicated backup circuits are easy to set up and may be used with all the routable protocols. There is no need to configure static routes, since the circuit will be disabled once the primary circuit (leased line) is restored. The disadvantage is that a separate switched circuit, a router port, and an adapt- er or DSU/CSU must be provided for each leased line.
Improving Network Availability Sample Networks The network in figure 13 is set up as follows: The leased lines and Ethernet LANs are configured normally. The switched circuits at the remote sites can use manual or V.25 bis adapters that can be configured to connect when the “circuit is enabled”...
Improving Network Availability Sample Networks Packet Switching Network Circuit Switching Network Figure 14. Packet-Switching Network with Circuit-Switching Backup The network in figure 14 is set up as follows: Connections to the packet-switching network are configured in a single subnet using either RIP or OSPF. OSPF is preferred since it detects failures and switches around failures faster than RIP.
Improving Network Availability Sample Networks The static routes defined for the circuit-switching network must have higher assigned costs than the routes used on the packet- switching network but equal preference. Thus, packet-switched routes are selected over circuit-switched routes to maximize throughput and minimize cost.
Improving Network Availability Application Recovery Inverse multiplexers are available from several companies including Ascend, Simplex, and Presticom. Additional features can include data compression, Switched 56 and PSTN switched-circuit types, and leased-line support with incremental switched-circuit bandwidth. Application Recovery One question that often arises when considering router networks with backup mechanisms is: “Will my application recover transparently after a primary circuit fails?”.
Improving Network Availability Application Recovery 3-30...
ISDN Wide Area Network Design: Dry Creek Joint Elem. School District Larry Angus, Network Consultant Hewlett-Packard Company Organization Overview The Dry Creek Joint Elementary School District is recognized as the fastest growing school district in the state of California. To maintain continuity of service with student increases averaging 47% for the last two years, the district has embarked on an aggressive use of technology.
To provide for the exchange of administrative and instructional information, the three school locations require connection with the district office. In partnership with Hewlett-Packard, the district has selected a two-phased strategy using extended local area network (LAN) technology. Phase I...
ISDN Wide Area Network Design: Dry Creek Joint Elem. School District Network Topology ISDN and point-to-point circuits are the only carrier options available to the district. The service costs of both options are shown in table 1. Table 1. WAN Cost Comparison (Q1/1993) Circuit Type Monthly Cost Installation Cost 56 Kbit/s point-to-point (4 locations)
ISDN Wide Area Network Design: Dry Creek Joint Elem. School District ISDN ISDN Traditionally, the point-to-point network depicted in figure 1 would be implemented with leased 56-Kbit/s circuits; however, the low cost of ISDN required a thorough investigation to see whether this option was appropriate for Dry Creek Schools.
ISDN Wide Area Network Design: Dry Creek Joint Elem. School District ISDN All of Dry Creek Joint Elementary School District is serviced as one business group by Roseville Telephone Company. With no usage charges, ISDN meets all of the district’s design criteria. The network as implemented is shown in figure 2.
ISDN Wide Area Network Design: Dry Creek Joint Elem. School District HP Routers HP Routers Initially, the district’s network will be implemented as a bridged network bridging IP. HP routers were selected for use in the Dry Creek design for the following reasons.
ISDN Wide Area Network Design: Dry Creek Joint Elem. School District ISDN Configurations District Office Router Basic configuration: Host-only bridging enabled, TFTP enabled, SNMP enabled, and Telnet enabled. The district office router is the originator and causes the terminal adapter to make the call when the router is booted and its DTR goes high.
ISDN Wide Area Network Design: Dry Creek Joint Elem. School District ISDN Configurations Remote Router Basic configuration: Host-only bridging enabled, TFTP enabled, SNMP enabled, and Telenet enabled. The remote-site router is the an- swerer and causes the terminal adapter to wait to answer the call when the router is booted and its DTR goes high.
ISDN Wide Area Network Design: Dry Creek Joint Elem. School District Performance Performance ISDN provides clear 64-Kbit/s channels for each point-to-point connection. This bandwidth will meet Dry Creek’s needs for approximately two to three years. Basic-rate terminal adapters that provide inverse multiplexing are becoming available.
ISDN Wide Area Network Design: Dry Creek Joint Elem. School District Performance 3-40...
Shining a Light on FDDI FDDI—the 100-Mbit/s Fiber Distributed Data Interface networking technology—is the solution for many of the new problems presented by changing corporate networks: Groups that previously had no need for communication now want network connections. Existing token ring and Ethernet backbones that are interconnected are now reaching their capacity.
Shining a Light on FDDI Technology Overview Technology Overview Fiber Distributed Data Interface (FDDI) is an ANSI and ISO specification (X3T9) for the transmission of data at high speeds, typically 100 Mbit/s, using fiber-optic cable as the transmission medium. Optical fiber technology offers networks a great degree of flexibility in bandwidth and topology design.
Shining a Light on FDDI Technology Overview FDDI and the OSI Model The FDDI standard is made up of four distinct parts: Physical Layer Medium Dependent (PMD) and Single Mode Fiber Physical Layer Medium Dependent (SMF-PMD) Physical Layer Protocol (PHY) Media Access Control (MAC) Station Management (SMT).
Shining a Light on FDDI Technology Overview The MAC corresponds to part of the data-link layer of the OSI model. The MAC standard defines the token-passing method as the means for acquiring access to the ring. It is responsible for frame and token construction, send- ing and receiving frames on the FDDI ring, and delivering LLC frames.
Shining a Light on FDDI How FDDI Works How FDDI Works FDDI is based on two counter-rotating 100-Mbps fiber-optic token- passing rings. If one ring should fail, FDDI automatically becomes a single, not dual, FDDI ring. The rings consist of point-to-point connections between adjacent stations.
Shining a Light on FDDI How FDDI Works Concentrators connect directly to the backbone of the ring, and provide indirect access to the ring for other devices. Concentrators support multiple DAS and SAS connections, and add a degree of fault tolerance to the network by isolating end nodes from the ring.
Shining a Light on FDDI How FDDI Works Access to the FDDI network is controlled by a token that circulates the primary ring. When a station has data to transmit, it must capture the token before it can transmit data onto the ring. Only one token may exist on the ring at any one time.
Shining a Light on FDDI How FDDI Works Optical Bypass Optical bypass can be used for fault tolerance to prevent ring segmenta- tion. Optical bypass switches maintain connectivity of the FDDI ring in the absence of power or during fault conditions in a station. Stations bypassed by optical bypass switches are effectively removed from the ring.
Shining a Light on FDDI How FDDI Works There are several limitations of optical bypass that a network designer must be aware of: When the bypass switch bypasses a station, the station is effectively removed, possibly allowing the maximum segment length to exceed 2 km.
Shining a Light on FDDI How FDDI Works Cabling Optical fiber has many advantages over traditional copper cabling. Fiber doesn’t emit electrical signals and is immune to electrical interference, making it secure and reliable. It is easy to manipulate because it is light- weight.
Shining a Light on FDDI How FDDI Works To calculate the cable loss between two adjoining stations, use the formula shown below: Attenuation = (Cable Len (km) x Attenuation/km) + (Splices x Attenuation per Splice) + (Connectors x Connector Attenuation) + (Loss at Transmit MIC) For example: 2 km fiber x 2.5 dB/km...
Shining a Light on FDDI Internetworking with HP Routers Internetworking with HP Routers HP’s FDDI link interfaces are compliant with the following ANSI X3T9.5 standards: Physical Medium Dependent (PMD) Physical Layer Protocol (PHY) Media Access Control (MAC) System Management (SMT) They also comply with RFC 1188, which specifies transmission of IP data- grams over FDDI media, and with IEEE 802.1 Parts D &...
Shining a Light on FDDI Internetworking with HP Routers Encapsulation Bridging There are many protocols that are non-routable and therefore must be bridged. These non-routable protocols must be encapsulated in an FDDI frame in order to be transported across the ring. Encapsulation is the bridge’s implementation that enables interconnection of similar networks over an FDDI network.
Shining a Light on FDDI Internetworking with HP Routers FDDI Translation Bridging To ensure multivendor interoperability, the bridge protocol should be based on the IEEE 802.1 Spanning Tree Protocol. Translation is required when bridging between LANs with different data-link-layer characteristics. For example, forwarding from an Ethernet to an 802.3 end station requires a translation.
Shining a Light on FDDI Internetworking with HP Routers If an Ethernet frame generated on LAN 1 is destined for LAN 2, the frame is translated as shown in figure 8. LAN 1 LAN 2 FDDI Ring LAN 1 Frame DA SA type data...
Shining a Light on FDDI Internetworking with HP Routers LAN 2 LAN 3 LAN 4 LAN 1 HP Router BR Port A Port B UNIX NFS PC Server Server Figure 9. FDDI Super-Server Configuration A file server is a very good candidate for a standalone FDDI network. In a standard configuration, a server would be connected directly to an Ethernet segment.
Using Synchronous Pass-Through to Consolidate Synchronous Traffic Routers and high-speed WAN links have been used to create corporate internetworks. These internetworks connect LANs and provide communica- tion among any systems and nodes attached to the LANs. There are many devices, however, such as SNA 3270 and 3770 terminals in most corporate networks, that are not connected to the extended LAN internetworks.
Using Synchronous Pass-Through to Consolidate Synchronous Traffic IBM PC SITE A SITE B Router Router HP 3000 IBM 3745 IBM 3090 SITE C IBM 3174 Router Figure 1. Synchronous Traffic Conveyed Through a High-Speed Extended LAN Network 3-58...
Using Synchronous Pass-Through to Consolidate Synchronous Traffic How It Works How It Works Synchronous ports on HP routers are used to provide the sync pass-through capability. Sync pass-through circuits are configured on the HP router using the point-to-point circuit type and the pass-through data-link-layer protocol. Once pass-through has been selected, the router software ignores the other circuit parameters.
Using Synchronous Pass-Through to Consolidate Synchronous Traffic How It Works HOST A HOST B X.25 X.25 SITE B SITE A PACKET PACKET SWITCH SWITCH ROUTER ROUTER TERM 1 ROUTER SITE C TERM 2 Figure 2. Bridging X.25 Traffic Using Sync Pass-Through 3-60...
Using Synchronous Pass-Through to Consolidate Synchronous Traffic Sync Pass-Through Encapsulation The PAD (packet assembler/dissembler) at site C is connected to the X.25 switch at site B using the sync pass-through ports labeled Traffic from terminal 1 to host B follows the path: terminal 1 to PAD PAD to site C router site C router to site B router...
Using Synchronous Pass-Through to Consolidate Synchronous Traffic Sync Pass-Through Encapsulation S YN C H R O N O U S FR AM E S YN C H R O N O U S P AS S - TH R O U G H P AC K E T Figure 3.
Using Synchronous Pass-Through to Consolidate Synchronous Traffic Selecting Sync Pass-Through Station Addresses Selecting Sync Pass-Through Station Addresses To configure sync pass-through, a station address must be selected for each sync pass-through port. Care must be taken to avoid selecting a station address already in use on the extended LAN.
Using Synchronous Pass-Through to Consolidate Synchronous Traffic Synchronous Traffic Requirements Synchronous Traffic Requirements The type of synchronous traffic that may be conveyed using sync pass- through is limited to HDLC and HDLC derivatives such as SDLC and LAPB. The following three conditions must be met for sync pass-through to function.
Using Synchronous Pass-Through to Consolidate Synchronous Traffic Physical Connections Physical Connections Synchronous ports on HP routers physically function as DTEs. Similarly, the synchronous ports on most devices, such as IBM 3270 cluster controllers and HP network interfaces, physically function as DTEs. Thus, the generally recommended practice is to connect these interfaces together using modems or modem eliminators (see figure 5).
Using Synchronous Pass-Through to Consolidate Synchronous Traffic Physical Connections Figure 6. Pin-Outs For V.35 and RS-232/V.24/V.28 Null-Modem Cables for 62-pin Direct Connection 3-66...
Using Synchronous Pass-Through to Consolidate Synchronous Traffic Special Considerations Figure 7. Pin-Outs for Null-Moden Cable for V.35 Connection Special Considerations Sync pass-through may be used only to provide communication between devices attached to synchronous ports on the router. Sync pass-through cannot be used to connect a synchronous device to a LAN-attached device.
Using Synchronous Pass-Through to Consolidate Synchronous Traffic Conclusion Conclusion Sync pass-through provides the opportunity to consolidate the traffic of many synchronous devices onto the corporate extended LAN internetwork. Consolidation of synchronous traffic can help reduce recurring monthly communication costs and costs associated with network support. Synchro- nous frames are transformed into LAN packets and bridged from source to destination.
Routing with OSPF The capabilities of an internet are largely determined by its routing protocol. An internet’s scalability, its ability to quickly route around failures, and the consumption of network resources by the routing machinery are all issues directly related to the routing protocol. With the release of HP router soft- ware revision 5.70, OSPF (Open Shortest Path First) is available in addition to RIP.
Routing with OSPF OSPF (Open Shortest Path First) is a new IP routing protocol. HP routers implement Version 2 of OSPF, which is documented in RFC 1247. Unlike RIP, OSPF employs a link-state algorithm (also referred to as a shortest-path-first (SPF) algorithm).
Routing with OSPF Routing Improvements OSPF has features that: Improve routing effectiveness and efficiency. Conserve IP address space and increase addressing flexibility. Enhance network security. Increase routing flexibility. These features make OSPF attractive for use on both small and medium- sized internets as well as large internets.
Routing with OSPF Routing Improvements Area and Router IDs. Both areas and routers have IDs (identifiers) that are used by OSPF to build its topological database. Both IDs are given in dotted decimal notation. This is the same notation used for IP addresses.
Routing with OSPF Routing Improvements Stub Areas. Stub areas are areas into which external routes are not propagated. The term external route has a particular significance in OSPF. Routing information provided to OSPF from any protocol other than OSPF itself is considered external. Thus routes provided by RIP or EGP as well as static routes are considered external.
Routing with OSPF Routing Improvements Table A. Metrics Based on Link Speed Link Speed Metric 100 Mbit/s 10 Mbit/s 4 Mbit/s 2.048 Mbit/s 1.544 Mbit/s 768 Kbit/s 512 Kbit/s 256 Kbit/s 128 Kbit/s 64 Kbit/s 56 Kbit/s 38.4 Kbit/s 19.2 Kbit/s 9.6 Kbit/s Area 126.96.36.199 Area 188.8.131.52...
Routing with OSPF Routing Improvements The OSPF standard does not provide guidance for metric selection or assignment. The easiest way to assign metrics is on the basis of link speed. Table A shows one possible scheme for selecting metrics based on link speed.
Routing with OSPF Routing Improvements Routers maintain detailed topological information about area(s) of which they are members, and they maintain summary information about networks in other areas. Area border routers (184.108.40.206 and 220.127.116.11 in figure 2) exchange summary information about their own areas with other area border routers. Network summary information received by an area border router is then transmitted to routers in its attached area(s).
Routing with OSPF Conserving IP Address Space NET 2 Metric 10 18.104.22.168 NET 3 NET 4 Metric 110 Metric 110 NET 1, Metric 40 NET 8, Metric 130 NET 9, Metric 40 NET 10, Metric 80 22.214.171.124 126.96.36.199 NET 5 NET 11, Metric 40 Metric 40 NET 12, Metric 50...
Routing with OSPF Conserving IP Address Space 170.200.1.x 170.200.2.x 170.200.5.x ROUTER ROUTER 170.200.8.x SUBNET MASK: 170.200.6.x 255.255.255.0 ROUTER ROUTER 170.200.7.x 170.200.4.x 170.200.3.x Figure 4. Subnetting in a RIP Internet The internet in figure 4 uses the IP class B address 170.200.x.x. This internet is subnetted using the subnet mask 255.255.255.0.
Routing with OSPF Conserving IP Address Space addresses will not be used. Thus, the subnet mask 255.255.255.252 is the minimum subnet mask that will provide only two addresses per subnet. Now that a suitable subnet mask for use on point-to-point links has been deter- mined, subnet numbers and addresses must be selected.
Routing with OSPF Conserving IP Address Space 170.200.1.x 170.200.2.x 188.8.131.52 ROUTER ROUTER 184.108.40.206 220.127.116.11 18.104.22.168 SUBNET MASK (LAN): 255.255.255.0 SUBNET MASK (WAN): 255.255.255.252 22.214.171.124 126.96.36.199 188.8.131.52 ROUTER ROUTER 184.108.40.206 170.200.4.x 170.200.3.x Figure 5. Internet with Variable-Length Subnet Masks Using the addresses in table C, the internet from figure 4 is shown in figure 5.
Routing with OSPF Addressing Flexibility range is also within the reserved LAN subnet address range and must not be assigned. The rule is to avoid assigning addresses within the reserved address ranges given by the subnet mask with the fewest number of bits in the subnet ID field.
Routing with OSPF Network Security Network Security Routing Authentication To enhance security, routing updates may optionally be authenticated using a simple password. When routing authentication is enabled, all OSPF proto- col packets are password protected. Passwords are from 1 to 8 characters and are configurable on a link basis.
Routing with OSPF Type-of-Service-Routing Table C. IP Types of Service Type of Service (TOS) Delay Throughput Reliability Service Description Default High Reliability High Throughput Low Delay High Throughput Shortest Path (FTP) ROUTER ROUTER Low Delay Shortest Path (Telnet) Figure 7. Routing Different Types of Service When multiple types of service are supported by HP routers, routing decisions can be based on the TOS requested in the header of a datagram.
Routing with OSPF Equal-Cost Multipath Equal-Cost Multipath Equal-cost-multipath routing is not yet available on HP routers. The following discussion is intended only to explain the equal-cost-multipath routing concept. ROUTER NET 2 NET 3 NET 1 NET 5 Metric B Metric C Metric A Metric A ROUTER...
Linking Up with Frame Relay Overview Frame Relay (FR) is a new wide area link technology. It was the first of several fast packet technologies to become commercially available. Other fast packet technologies include Switched Multimegabit Data Service (SMDS) and asynchronous transfer mode (ATM). Frame Relay Router Network...
Linking Up with Frame Relay Overview Frame Relay switches and/or the network provider. Frame Relay offers high performance, multiple access, and high reliability. This combination makes Frame Relay very well suited for LAN-to-LAN internetworking. High performance or, rather, high throughput with low latency (delay introduced by the network), is achieved through a variety of factors.
Linking Up with Frame Relay Overview Frame Relay Connections Figure 2 shows another view of the Frame Relay network. All of the routers are connected together in a fully meshed topology. Each router has a connec- tion, a permanent virtual circuit (PVC), to each of the other routers in the network.
Linking Up with Frame Relay History Ports and PVCs Two important Frame Relay access characteristics are port speed and committed information rate (CIR). These characteristics govern the rate at which data may be transmitted into the network. Port speed is the maximum rate at which data will be Port Speed accepted by the boundary Frame Relay switch to which a router is connected.
Linking Up with Frame Relay History The first formal Frame Relay specification was developed by the Frame Relay Forum (FRF), a group of companies that included Digital Equipment Corp., Cisco, Northern Telecom, and StrataCom. This specification, released in September, 1990, was based upon existing standards and ongoing work in the ANSI T1S1 committees.
Linking Up with Frame Relay Frame Relay Data-Link Interface Frame Relay Data-Link Interface Table 1 shows the structure of frames transmitted by HP routers on Frame Relay networks. This frame structure was defined in the FRF’s “Frame Relay Specification”. The frame structure was based upon CCITT Recommenda- tion Q.921, “LAPD”, and from work being done in the ISDN area and in the ANSI committee T1S1.
Linking Up with Frame Relay Frame Relay Data-Link Interface Like LAPB (the link-access procedure used on X.25 networks) and LAPD (the link-access procedure used in ISDN networks), Q.922 frames are delimited by a flag character (7E hex), and for data integrity, a frame check sequence (CCITT-CRC) is appended to the user data.
Linking Up with Frame Relay Frame Relay Data-Link Interface Congestion Control The most interesting aspects of the Q.922 address field are the three bits used for congestion control—FECN, BECN, and DE. FECN BECN Figure 3. Congestion on a Frame Relay PVC Figure 3 shows a Frame Relay network with two attached routers.
Linking Up with Frame Relay Frame Relay Data-Link Interface Congestion notifications are ignored for a couple of reasons. First, routers do not have good mechanisms for notifying end systems on attached LANs to slow their transmissions to a particular destination. The TCP/IP and OSI transport layers, however, have implicit congestion avoidance mechanisms.
Linking Up with Frame Relay Frame Relay Data-Link Interface When a packet other than TCP/IP, such as Novell IPX, must be transmitted, RFC 1294 specifies that the NLPID field is encoded with 80 hex, which indicates that a Subnetwork Access Protocol (SNAP) header follows. The SNAP header and additional data will be appended to the NLPID field and used to encode which of the other routable protocols the Frame Relay frame contains.
Linking Up with Frame Relay Frame Relay Data-Link Interface Bridging Over Frame Relay The encoding of the NLPID field for bridged packets is the same as that used for network layers not having a specific NLPID value—80 hex. This again specifies a SNAP header;...
Linking Up with Frame Relay Local Management Interface At this point we have looked at Q.922, the Frame Relay data-link interface. We have seen how multiprotocol user data is encoded and exchanged in a Frame Relay network. In the next section we will see how the Frame Relay link and each PVC is activated (or deactivated) and how the status of each link and the associated PVCs is maintained.
Linking Up with Frame Relay Local Management Interface There are two types of Status Enquiry/Status messages exchanged by routers and the Frame Relay network: Link Integrity Verification (Keep Alive). This message is sent periodically to maintain link integrity, or in other words, keep the link alive.
Linking Up with Frame Relay Local Management Interface This sequence of events is shown in figure 4. Both the “poll interval” and the “interval between full polls” are configurable parameters, the values of which should be set in accordance with the network provider’s subscription parameters.
Linking Up with Frame Relay Local Management Interface Table 7. DLCI Status bits returned in “Status” message Value Description PVC is already present PVC is new Active PVC is inactive (PVC is deleted) Acitve PVC is active Figure 5 shows four routers attached to a Frame Relay network. Each router has a PVC to each of the other routers on the network.
Linking Up with Frame Relay Local Management Interface to the network. The network will respond with a full status reply, which indicates that DLCI 100 is available (active and new bits set). Both routers are now able to communicate. When R3 comes on line and sends its full status poll to the network, the network will respond with a full status reply indicating that DLCIs 131 and 132 are available.
Linking Up with Frame Relay Address Resolution Address Resolution Internet RFC 1293, “Inverse Address Resolution Protocol”, describes additions to ARP (Address Resolution Protocol) that are intended to reduce the amount of address resolution traffic in a Frame Relay network. An ARP packet is sent whenever a TCP/IP system wants to communicate with a system it hasn’t communicated with recently.
Linking Up with Frame Relay HP Implementation—Summary Emulate either user device or Frame Relay network. User device/ network emulation can be used to test or troubleshoot particular capabilities of an interface. The “Test Manager” in the emulation package is a comprehensive environment for automating the entire array of Frame Relay test functions.
Linking Up with Frame Relay HP Implementation—Summary Data-Link Layer Specification: CCITT Rec. Q.922 (two-, three-, and four-byte addressing formats). Compatible with Frame Relay Forum’s “Frame Relay Specification” and ANSI T1.618. CCITT Rec. Q.922, “PreDraft Standard” and the earlier March and November versions.
Linking Up with Frame Relay HP Implementation—Summary Frame Relay MIB: The Frame Relay information base contains the following three tables and associated entries: Data-Link-Connection Management Interface Table (1 DLCMI table per physical circuit) 1. LMI in use (FRF LMI, ANSI Annex D) 2.
Frame Relay Network Design: Fleet Call, Inc. Wendy Pinos, Network Consultant Hewlett-Packard Company Company Overview Fleet Call, Inc., is a rapidly-expanding wireless communication company, located in the major market areas across the United States. Fleet Call is currently the nation’s second largest provider of specialized mobile radio services.
Frame Relay Network Design: Fleet Call, Inc. Business Need Business Need To support the business services, Fleet Call is installing a series of HP 9000 UNIX systems. These systems will run subscriber maintenance and financial applications critical for Fleet Call’s day-to-day operations. The HP 9000 systems are housed in a centralized data center.
Frame Relay Network Design: Fleet Call, Inc. Network Topology At the second tier, each of the backbone sites concentrate wide area connections from the remote offices located in that market area. These nearby offices or “tail sites” will rely on the backbone connection for communication to other market areas or the data center.
Frame Relay Network Design: Fleet Call, Inc. Network Topology The backbone sites are equipped with a larger network router that concentrates the lines from all the tail sites and also provides a connection to the backbone network. The backbone router will also concentrate the local LAN subnets within the building itself.
Frame Relay Network Design: Fleet Call, Inc. Network Topology The traditional design for wide area networks uses point-to-point dedicated circuits. Dedicated circuits provide guaranteed bandwidth with high perform- ance. With point-to-point circuits, Fleet Call could still implement the two- tiered network described above. However, the point-to-point circuits offer only a single circuit on the backbone, so Fleet Call would need to implement a meshed network of multiple point-to-point circuits to achieve any kind of link redundancy.
Frame Relay Network Design: Fleet Call, Inc. Network Topology A number of alternative backbone technologies are emerging in the industry. Long-distance carriers have made the most progress in providing frame relay services. Frame relay bases its design on packet-switching technology, as does X.25.
Frame Relay Network Design: Fleet Call, Inc. Network Topology Both the dedicated circuit and frame relay approaches have merit. For the final wide area topology, Fleet Call selected a combination of these solutions. For the high-speed network backbone that provides mission- critical connections, a frame relay network is used.
Frame Relay Network Design: Fleet Call, Inc. Performance Performance As of mid-1993, Fleet Call continues to roll out the network to remote sites. Performance will depend on the bandwidth of the remote links. Fleet Call is closely monitoring the utilization of the network and can add bandwidth to the frame relay backbone link as required.
IP... 2-81 10Base2... 1-10 architecture... 1-21–1-34 10Base5... 1-10 area number... 2-117–2-118 200 series specifics... 1-3, 1-10, 1-21–1-23 areas 400 series specifics... 1-3, 1-10, 1-21–1-23 DECnet... 1-7, 2-116–2-117, 2-121–2-123 600 series ... 1-3, 1-9, 1-23, 1-25–1-26 OSPF... 1-6, 1-32, 2-66 650 specifics...
buffer... 1-23, 1-27–1-28 Configuration Editor... 1-18, 2-112, 2-119, 2-123 bus... 1-22–1-23, 1-25–1-26, 1-28 console... 1-9, 1-15–1-20, 2-85, 2-93, 2-124 See also RS-232 console port controller chip... 1-22–1-23, 1-25, 1-27–1-28 convergence... 2-66 cables coprocessor RS-232... 1-11–1-12 See processor chip RS-422/449... 1-11–1-12 cost...
device management... 1-17, 2-85, 2-90, 2-93–2-94, Ethernet... 1-3–1-7, 1-10, 1-23–1-24, 1-27, 2-3, 2-77, 2-124 2-93, 2-107–2-108 DFS: Distributed File System (DECnet)... 2-116 EtherTalk... 2-107 DHCP: Dynamic Host Configuration Protocol... event log... 1-16–1-17, 2-93, 2-124 2-86–2-89 export route filter... 1-32, 2-79–2-80, 2-94 diagnostic services (NetWare)...
Internet Control Message Protocol See ICMP half router for AppleTalk... 2-108 Internet Datagram Protocol hardware architecture... 1-9, 1-21–1-28 See IDP HDLC... 1-16, 2-123 Internet Packet Exchange Hello messages for DECnet... 2-121 See IPX help... 1-18 Internet Protocol hierarchical routing (DECnet)... 2-116–2-118, See IP 2-121–2-123 internetwork...
2-119 See IPXWAN media interface connector See MIC memory... 1-22–1-23, 1-25–1-28 memory bus... 1-25 Kerberos... 2-56 Message Handling Service (MHS) for NetWare... 2-96 MHS: Message Handling Service (NetWare)... 2-96 MIB... 1-17, 1-20, 2-85, 2-124 LAN types supported... 1-3, 1-10–1-11, 1-24, 2-95, MIC: media interface connector for FDDI rings...
node... 1-8, 1-17, 2-55, 2-58–2-59, 2-64, 2-68, 2-95, point-to-point WAN link... 1-11–1-13, 1-19, 2-72, 2-97–2-98, 2-107–2-108, 2-110–2-114, 2-116–2-118, 2-123 2-120–2-121 poison reverse (in RIP)... 2-66 node bypassing in FDDI... 1-11 port node identifier controller... 1-22–1-23, 1-25, 1-27–1-28 See node number filter...
RIP... 1-5, 1-7–1-8, 2-65–2-67, 2-69–2-70, 2-74, 792... 2-94 2-79–2-80, 2-94 826... 2-94 See also routing protocols and routing services 854... 2-94 Routing Table Maintenance Protocol... 1-8, 868... 2-94 2-112–2-114 877... 1-8, 1-12, 2-94 SNMP... 1-20 Rgetat command... 2-114 spanning tree... 1-3–1-4, 2-3 Rgetis command...
Novell IPX... 1-6, 1-8, 1-15, 1-19, 1-33, 2-92, distribution... 1-16 2-95–2-106 See also operating system or configuration XNS... 1-7–1-8 SONIC... 1-23, 1-27 routing table... 1-16–1-17, 1-20, 1-29, 1-32–1-33, source routing... 1-5, 1-29, 2-93, 2-115 2-64–2-65, 2-67, 2-74–2-75, 2-80, 2-85, 2-93, source-routing bridge...
TFTP: Trivial File Transfer Protocol... 1-15–1-17, V.35 WAN interface... 1-11–1-12 2-56, 2-81, 2-85, 2-90, 2-94 V.36 thick coaxial LAN connection... 1-10 See RS-422/449 VAX... 2-115 thin coaxial LAN connection... 1-10 ThinLAN... 1-10 Videotex... 2-116 throughput virtual circuit... 1-12 See performance virtual IP host on non-IP networks...