3Com SuperStack 3 3250 Implementation Manual
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3Com SuperStack 3 3250 Implementation Manual

3com superstack 3 series
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See also: User Manual
SuperStack
Switch 3226 and Switch 3250
Implementation Guide
3CR17500-91
3CR17501-91
http://www.3com.com/
Part No. DUA1750-0BAA01
Published December 2003
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Summary of Contents for 3Com SuperStack 3 3250

  • Page 1 SuperStack Switch 3226 and Switch 3250 Implementation Guide 3CR17500-91 3CR17501-91 http://www.3com.com/ Part No. DUA1750-0BAA01 Published December 2003 ®...
  • Page 2 3Com Corporation reserves the right to revise this documentation and to make changes in content from time USA 01752-3064 to time without obligation on the part of 3Com Corporation to provide notification of such revision or change. 3Com Corporation provides this documentation without warranty, term, or condition of any kind, either implied or expressed, including, but not limited to, the implied warranties, terms or conditions of merchantability, satisfactory quality, and fitness for a particular purpose.

  • Page 3: Table Of Contents

    ONTENTS BOUT UIDE Conventions Related Documentation Documentation Comments WITCH EATURES What is Management Software? Switch Features Explained Aggregated Links Auto-negotiation Configuration Save and Restore Multicast Filtering Rapid Spanning Tree Protocol Switch Database Traffic Prioritization Rate Limiting RMON Broadcast Storm Control...
  • Page 4 STP Example STP Configurations Using STP on a Network with Multiple VLANs SING THE WITCH What is the Switch Database? How Switch Database Entries Get Added Switch Database Entry States SING RAFFIC ANAGEMENT What is Traffic Prioritization? How Traffic Prioritization Works...
  • Page 5 Creating New VLANs VLANs: Tagged and Untagged Membership VLAN Configuration Examples Using Untagged Connections Using 802.1Q Tagged Connections SING UTOMATIC How Your Switch Obtains IP Information How Automatic IP Configuration Works Automatic Process Important Considerations Server Support TATISTICS IP C...
  • Page 6 Access Control Lists How Access Control List Rules Work Port Security What is Network Login? How Network Login Works Important Considerations What is Switch Management Login? Benefits of RADIUS Authentication How RADIUS Authentication Works Important Considerations What is RADIUS? IP R...
  • Page 7 ULES Configuration Rules for Gigabit Ethernet Configuration Rules for Fast Ethernet Configuration Rules with Full Duplex ETWORK ONFIGURATION Simple Network Configuration Example Desktop Switch Example Advanced Network Configuration Example Edge Switch Example IP A DDRESSING IP Addresses Simple Overview Advanced Overview...

  • Page 9: About This Guide

    The terms Switch 3226 and Switch 3250 are used when referring to the 3Com SuperStack 3 Switch 3226 and 3Com SuperStack 3 Switch 3250. The term Switch is used when referring to information that applies to both Switches.

  • Page 10: Conventions

    BOUT UIDE Conventions Table 1 Table 1 Notice Icons Table 2 Text Conventions Convention Screen displays This typeface represents information as it appears on the <syntax> Commands The words “enter” and “type” Keyboard key names If you must press two or more keys simultaneously, the key Words in italics Table 2 list conventions that are used throughout this guide.

  • Page 11: Related Documentation

    SuperStack 3 Switch 3226 and SuperStack 3 Switch 3250 Getting Started Guide This guide contains: all the information you need to install and set up the Switch in its default state information on how to access the management software to begin managing your Switch.
  • Page 12 Please include the following information when contacting us: Example: Please note that we can only respond to comments and questions about 3Com product documentation at this e-mail address. Questions related to technical support or sales should be directed in the first instance to your network supplier.

  • Page 13: Switch Features

    HTML format on the CD-ROM that accompanies your Switch. What is Your Switch can operate in its default state. However, to make full use of Management the features offered by the Switch, and to change and monitor the way it...

  • Page 14: Aggregated Links

    Aggregated links are connections that allow devices to communicate using multiple links in parallel. Your Switch supports one aggregated link using the two 10/100/1000 and SFP ports (25-26 on the Switch 3225, 49-50 on the Switch 3250). Aggregated links provide two benefits: The Switch implements the IEEE 802.3ad standard for link aggregation.

  • Page 15: Configuration Save And Restore

    The Configuration Save and Restore feature allows the configuration of and Restore your Switch to be saved as a file on a remote server, or to be restored onto the Switch from a file on a remote server. The configuration information is stored in an ASCII text file.

  • Page 16: Multicast Filtering

    CD-ROM that accompanies your Switch. Multicast Filtering Multicast filtering allows the Switch to forward multicast traffic to only the endstations that are part of a predefined multicast group, rather than broadcasting the traffic to the whole network.

  • Page 17: Switch Database

    Features”. Switch Database The Switch Database is an integral part of the Switch and is used by the Switch to determine if a packet should be forwarded, and which port should transmit the packet if it is to be forwarded.

  • Page 18: Broadcast Storm Control

    For more information about VLANs, see LANs”. Automatic IP Your Switch can have its IP information automatically configured using a Configuration DHCP server. Alternatively, you can manually configure the IP information. For more information about how the automatic IP configuration feature...

  • Page 19: Network Login

    Dynamic routing allows the Switch to adjust automatically to changes in network topology or traffic. Routing Information Protocol (RIP) RIP is a dynamic routing protocol that allows the Switch to adjust automatically to changes in network topology or traffic. Routes are calculated between networks automatically.
  • Page 20 1: S HAPTER WITCH EATURES VERVIEW...

  • Page 21: Optimizing Bandwidth

    Command Line Interface (CLI) commands that you require to manage the Switch please refer to the Management Interface Reference Guide supplied in HTML format on the CD-ROM that accompanies your Switch. Port Features The default state for all the features detailed below provides the best configuration for most users.

  • Page 22: Flow Control

    Ports operating at 1000 Mbps support full duplex mode only. Flow Control All Switch ports support flow control, which is a mechanism that prevents packet loss during periods of congestion on the network. Packet loss is caused by one or more devices sending traffic to an already overloaded port on the Switch.

  • Page 23: Aggregated Links

    10/100 ports. When an SFP module is inserted it has priority over the 10/100/1000 port of the same number (25-26 on the Switch 3226, 49-50 on the Switch 3250). The corresponding 10/100/1000 port is disabled when an SFP module is present.
  • Page 24 In this example, if link 1 fails, the data flow between X and B is remapped to physical link 2. The re-mapping occurs as soon as the Switch detects that a member link has failed — almost instantaneously. As a result, aggregated link configurations are extremely resilient and fault-tolerant.

  • Page 25: Implementing 802.3Ad Aggregated Links

    LACP) it will adopt the configuration settings of the aggregated link. When a port leaves an aggregated link its original configuration settings are restored. Your Switch supports a single aggregated link comprising: both 10/100/1000 ports both SFP ports one SFP port and one 10/100/1000 port A LinkUp / LinkDown trap will only be sent for individual links.
  • Page 26 If the link state on any of the ports in an aggregated link becomes inactive due to link failure, then the Switch will automatically redirect the A member link port can only belong to one aggregated link.

  • Page 27: Aggregated Link - Manual Configuration Example

    Add the ports 5 and 7 on the specified unit to the aggregated link. 2 Prepare ports 25 and 26 on the Switch 3226 (or ports 49 and 50 if you are configuring a Switch 3250) for aggregated links. To do this:...
  • Page 28 2: O HAPTER PTIMIZING ANDWIDTH 3 Connect port 5 on the core Switch to port 25 on the Switch 3226. 4 Connect port 7 on the upper Switch to port 26 on the Switch 3226.

  • Page 29: Using Multicast Filtering

    Multicast filtering improves the performance of networks that carry multicast traffic. This chapter explains multicasts, multicast filtering, and how multicast filtering can be implemented on your Switch. It covers the following topics: For detailed descriptions of the Web interface operations and the...

  • Page 30: Benefits Of Multicast

    3: U HAPTER SING ULTICAST A multicast packet is identified by the presence of a multicast group address in the destination address field of the packet’s IP header. Benefits of Multicast The benefits of using IP multicast are that it: There are situations where a multicast approach is more logical and efficient than a unicast approach.

  • Page 31: Multicast Filtering And Your Switch

    The Switch 3226 and Switch 3250 are compatible with any device that conforms to the IGMP v2 protocol. The Switch does not support IGMP v3. If you have an IGMP v3 network, you should disable IGMP snooping for the Switch using the snoopMode command on the Web Interface.

  • Page 32: How Igmp Supports Ip Multicast

    3 When the report packet arrives at a port on a Switch with IGMP multicast learning enabled, the Switch learns that the port is to forward traffic for the multicast group and then forwards the packet to the router.
  • Page 33 The querier is always the device with the lowest IP address in the subnetwork. It can be a router or a Layer 2 switch. The network traffic flows most efficiently if the querier is the closest device to the sources of IP multicast traffic.

  • Page 34: Role Of Igmp In Ip Multicast Filtering

    To further refine the IP multicast delivery process and maximize Multicast Filtering bandwidth efficiency, the Switch filters IP multicast packets on appropriate ports using a process called IGMP snooping. Both bridged interfaces and routed interfaces record which ports receive host IGMP...

  • Page 35: Using Resilience Features

    — one of the major causes of broadcast storms. RSTP is enabled by default on your Switch. To be fully effective, RSTP or STP must be enabled on all Switches in your network.

  • Page 36: Rapid Spanning Tree Protocol (Rstp)

    SING ESILIENCE The protocol is a part of the IEEE Std 802.1w-2001, bridge specification. To explain RSTP more effectively, your Switch will be referred to as a bridge. Rapid Spanning Tree The Rapid Spanning Tree (RSTP) is an enhanced Spanning Tree feature.
  • Page 37 What is STP? As an example, Figure 5 shows a network containing three LAN segments separated by three bridges. With this configuration, each segment can communicate with the others using two paths. Without STP enabled, this configuration creates loops that cause the network to overload. Figure 5 A network configuration that creates loops Figure 6 shows the result of enabling STP on the bridges in the...

  • Page 38: How Stp Works

    Bridge Identifier, the more likely the bridge is to become the Root Bridge. The Bridge Identifier is calculated using the MAC address of the bridge and a priority defined for the bridge. The default priority of your Switch is 32768. Figure 7, the STP process...

  • Page 39: Stp Calculation

    Each port to have a cost. This specifies the efficiency of each link, usually determined by the bandwidth of the link — the higher the cost, the less efficient the link. a Switch. Table 3 Default port costs Port Speed...

  • Page 40: Stp Reconfiguration

    4: U HAPTER SING ESILIENCE EATURES bridge is configured to forward traffic only between its Root Port and the Designated Bridge Ports for the respective network segments. All other ports are blocked, which means that they are prevented from receiving or forwarding traffic.
  • Page 41 How STP Works Figure 8 Port costs in a network Bridge A has the lowest Bridge Identifier in the network, and has therefore been selected as the Root Bridge. Because Bridge A is the Root Bridge, it is also the Designated Bridge for LAN segment 1.

  • Page 42: Stp Configurations

    Configuration 2 — Redundancy through Meshed Backbone In this configuration, four Switch units are connected in a way that creates multiple paths between each one. STP discovers the duplicate paths and blocks two of the links. If an enabled link breaks, one of the disabled links becomes re-enabled, therefore maintaining connectivity.
  • Page 43 How STP Works Figure 9 STP configurations...

  • Page 44: Using Stp On A Network With Multiple Vlans

    For example, are connected using the 802.1Q-tagged link between Switch B and Switch C. By default, this link has a path cost of 100 and is automatically blocked because the other Switch-to-Switch connections have a path cost of 36 (18+18). This means that both VLANs are now subdivided — VLAN...

  • Page 45: Switch Database

    What is the Switch The Switch Database is used by the Switch to determine where a packet Database? should be forwarded to, and which port should transmit the packet if it is to be forwarded. The database contains a list of entries — each entry contains three items:...

  • Page 46: Switch Database Entry States

    Databases entries can have three states: Entry States ATABASE Learned — The Switch has placed the entry into the Switch Database when a packet was received from an endstation. Note that: Learned entries are removed (aged out) from the Switch Database if the Switch does not receive further packets from that endstation within a certain period of time (the aging time).

  • Page 47: Using Traffic Management

    The Switch 3226 and Switch 3250 have two features that allow you to manage the traffic on your network: What is Traffic...

  • Page 48: How Traffic Prioritization Works

    Switch without being delayed by lower priority data. Traffic prioritization uses the four traffic queues that are present in the hardware of the Switch to ensure that high priority traffic is forwarded on a different queue from lower priority traffic. High priority traffic is given preference over low priority traffic to ensure that the most critical traffic gets the highest level of service.

  • Page 49: Diffserv Traffic Classification

    How Traffic Prioritization Works The 802.1D standard specifies eight distinct levels of priority (0 to 7), each of which relates to a particular type of traffic. The priority levels and their traffic types are shown in Figure 11 in order of increasing priority. You cannot alter the mapping of priority levels 0 - 7 to the traffic queues.

  • Page 50: Ip Port Traffic Classification

    The transmitting endstation tags a packet with source and destination port numbers. When the packet is received, the Switch places the packet in the queue that corresponds to the destination IP port number of the packet. If there is no priority set against the IP port number then the...

  • Page 51: Traffic Prioritization And Your Switch

    Figure 13 queues. Traffic Prioritization Your Switch sorts traffic based on Class of Service. It does not mark or and your Switch remark a packet with a tag, but prioritizes the packet based on its existing tag. Tags can be added to packets by either the originating device or another edge switch elsewhere on the network.

  • Page 52: Limiting The Rate Of A Port

    Configuring traffic prioritization CoS can be configured on your Switch using the Web interface or via the Command Line Interface (CLI). For a detailed description of the commands that you require to configure CoS refer to the Management Interface Reference Guide supplied in HTML format on the CD-ROM that accompanies your Switch.

  • Page 53: Configuring Rate Limiting

    Switch is limited rather than the traffic arriving at the Switch. This ensures that the traffic is prioritized before rate limiting is applied, and that the lowest priority packets are dropped first.
  • Page 54 6: U HAPTER SING RAFFIC ANAGEMENT...

  • Page 55: Status Monitoring And Statistics

    The workstation does not have to be on the same network as the Switch and can manage the Switch by in-band or out-of-band connections. The RMON Groups The IETF define groups of Ethernet RMON statistics.
  • Page 56 7: S HAPTER TATUS ONITORING AND TATISTICS Statistics The Statistics group provides traffic and error statistics showing packets, bytes, broadcasts, multicasts and errors on a LAN segment or VLAN. Information from the Statistics group is used to detect changes in traffic and error patterns in critical areas of your network.

  • Page 57: Benefits Of Rmon

    Benefits of RMON Using the RMON features of your Switch has three main advantages: RMON and the The RMON support provided by your Switch 3226 and Switch 3250 is Switch detailed in Table 4 RMON support supplied by the Switch...

  • Page 58: Alarm Events

    When using the RMON features of the Switch, note the following: Alarm Events You can define alarms for the Switch. The events that you can define for each alarm and their resulting actions are listed in Table 5 Alarm Events...

  • Page 59: Setting U P Virtual Lans

    Setting up Virtual LANs (VLANs) on your Switch increases the efficiency of your network by dividing the LAN into logical, rather than physical, segments which are easier to manage. This chapter explains more about the concept of VLANs and explains how they can be implemented on your Switch.

  • Page 60: Benefits Of Vlans

    Devices within each VLAN can only communicate with other devices in the same VLAN. If a device in VLAN Marketing needs to communicate with devices in VLAN Finance, the traffic must pass through a routing device or Layer 3 Switch. Switch B Finance Department...

  • Page 61: Vlans And Your Switch

    The IEEE Std 802.1Q-1998 allows each port on your Switch to be placed The standard requires that you define the following information about each VLAN on your Switch before the Switch can use it to forward traffic: The Default VLAN A new or initialized Switch contains a single VLAN, the Default VLAN.
  • Page 62 VLANs on the switch and how an additional VLAN can be used to aggregate two VLANs. Figure 15 Two VLANs connected to a core switch using a third VLAN The Switch can also be used to route traffic between VLANs on a Layer 2 switch. Figure 16 shows how a Layer 3 switch can be used to redirect traffic from one VLAN to another.

  • Page 63: Creating New Vlans

    The IEEE Std 802.1Q-1998 defines how VLANs operate within an open packet-switched network. An 802.1Q compliant packet carries additional information that allows a Switch to determine to which VLAN the port belongs. If a frame is carrying the additional information, it is known as...

  • Page 64: Vlan Configuration Examples

    The example shown in endstations and servers using untagged connections. Ports 1, 2 and 3 of the Switch belong to VLAN 1, ports 10, 11 and 12 belong to VLAN 2. VLANs 1 and 2 are completely separate and cannot communicate with each other.

  • Page 65: Using 802.1Q Tagged Connections

    2 Add ports to the VLANs Add ports 10, 11 and 12 of the Switch as untagged members to VLAN 2. You can use the Switch Web Interface to change VLAN configuration. VLAN configuration can be found at Bridge > VLAN.
  • Page 66 8: S HAPTER ETTING IRTUAL...

  • Page 67: Using Automatic Ip Configuration

    Your Switch has two ways to obtain its IP address information: Obtains IP Information If you select an option for no IP configuration the Switch will not be accessible from a remote management workstation on the LAN. In addition, the Switch will not be able to respond to SNMP requests.

  • Page 68: How Automatic Ip Configuration Works

    The dynamic nature of automatically configured IP information means that a Switch may change its IP address whilst in use. Your DHCP server may allow you to reserve an IP address so that your Switch will always be allocated the same IP address.
  • Page 69 Important Considerations If you want DHCP to be the method for automatic configuration, make sure that your DHCP servers are operating normally before you power on your Switch.
  • Page 70 9: U IP C HAPTER SING UTOMATIC ONFIGURATION...

  • Page 71: Making Your

    Before enabling trusted IP 3Com recommends that you add the IP address of your management station to the list of trusted IP addresses. The trusted IP feature restricts network access to the management interfaces of the Switch.

  • Page 72: Securing Access To The Web Interface

    10: M HAPTER AKING interface of the Switch using console port, even if you have denied all access to the Switch using the trusted IP feature. Securing Access to The Switch 3226 and Switch 3250 support HTTPS, allowing secure access the Web Interface to the Web interface of the Switch.

  • Page 73: Securing Access To The Command Line Interface

    Certificate Authority (CA) but security will not be otherwise affected. If you cannot generate an X.509 certificate yourself, you can buy one from one of the Certifying Authorities or your ISP. Each Switch requires its own X.509 certificate. Securing Access to...

  • Page 74: How Access Control List Rules Work

    As a result of the above rule, the packet matches the parameters of the rule and will be blocked. Port Security The Switch 3226 and Switch 3250 support the following port security modes, which you can set for an individual port or a range of ports: ETWORK ECURE Packet destination IP address: 10.101.67.45...

  • Page 75: What Is Network Login

    Login? unblocking access on a per-port basis. When a client device attempts to connect to a Switch port, the user is challenged to provide their identity and authentication credentials in the form of a user name and password. The user information is then sent to a remote RADIUS server in the network for authentication.

  • Page 76: Important Considerations

    This section contains some important considerations when using Network Considerations Login on the Switch 3226 and Switch 3250. ETWORK ECURE Figure 19. The Switch does not interpret or store this Network Access Client (Client Device) Authentication Information Before you enable Network Login you must ensure that: RADIUS has been configured on the Switch.

  • Page 77: What Is Switch Management Login

    What is Switch If you intend to manage the Switch using the Web interface or the Management Command Line Interface, you need to log in with a valid user name and Login? password. For further information on managing the Switch, see the “Setting Up For Management”...

  • Page 78: How Radius Authentication Works

    RADIUS server. The information is authenticated by the server and a valid user is allowed to login to the Switch. An invalid user will receive a reject response and is not allowed to login to the Switch.

  • Page 79: Important Considerations

    Switch via the console port and continue to manage it. The Web interface and Telnet do not revert to the local database, and the user will not be able to log in to the Switch via the Web interface or Telnet.

  • Page 80: What Is Radius

    RADIUS is defined in the RFCs 2865 and 2866, “Remote Authentication Dial-in User Service (RADIUS)” and “RADIUS Accounting”. Network Login, a method of port-based access control, and Switch Management Login, used to control administrative access, both utilize the RADIUS protocol.

  • Page 81: Ip Routing

    For detailed descriptions of the web interface operations and the command line interface (CLI) commands that you require to manage the Switch please refer to the Management Interface Reference Guide supplied in HTML format on the CD-ROM supplied with your Switch or on the 3Com Web site. OUTING...

  • Page 82: What Is Routing

    OUTING What is Routing? Routing distributes packets over potentially dissimilar networks. A router is the device that accomplishes this task. Your Switch, as a Layer 3 device, can act as a router. Routers typically: Routing in a Your Switch allows you to both perform routing and switching within Subnetworked your network.

  • Page 83: What Is Ip Routing

    What is IP Routing? An IP router, unlike a bridge, operates at the network layer of the OSI Reference Model. The network layer is also referred to as Layer 3. An IP router routes packets by examining the network layer address (IP address).

  • Page 84: Benefits Of Ip Routing

    IP routers use the following elements to transmit packets: Router Interfaces A router interface connects the router to a subnetwork. On your Switch, more than one port can connect to the same subnetwork. Each router interface has an IP address and a subnet mask. This router interface address defines both the number of the network to which the router interface is attached and its host number on that network.

  • Page 85: Routing Tables

    Figure 23 Routing Interfaces Network 1 158.101.1.1 = Interface 1 = Interface 2 = Interface 3 Routing Tables With a routing table, a router or host determines how to send a packet toward its ultimate destination. The routing table contains an entry for every learned and locally defined network.

  • Page 86: Default Route

    If the destination MAC address is the internal router port on this Switch, the packet is routed (Layer 3). If the destination MAC address is not one of the router interfaces MAC addresses on this Switch, then the packet will be switched and is forwarded according to the IEEE 802.1D protocol.

  • Page 87: Multiple Ip Interfaces Per Vlan

    This model allows the Switch to route the packet first, and then if the packet cannot be routed, give the packet to Layer 2 to be bridged by the VLAN. This scheme gives you the flexibility to define router interfaces on top of several bridge ports.

  • Page 88: Implementing Ip Routing

    This is not a user configurable parameter. VLAN interface index — The number of the VLAN that is associated with the IP interface. When the Switch prompts you for this option, the menu identifies the available VLAN indexes. ) or unavailable (...
  • Page 89 Flush the ARP cache regularly if you set the age time to 0. Set up a default route. The Switch uses the default route to forward packets that do not match any other routing table entry. You may want to use the default route in place of routes to numerous destinations that all have the same gateway IP address.

  • Page 90: Ip Routing Protocols

    Basic RIP Parameters There are several parameters to consider when you set up RIP for your network. When you configure an IP interface, the Switch already has the RIP parameters set to the defaults listed in Static routes take precedence over dynamically learned routes to the same destination.

  • Page 91: Router Mode

    Send Mode Receive Mode Poison Reverse Advertisement Address * These RIP parameters apply to the entire Switch. All other parameters are defined per interface. † The Cost value cannot be altered, it is fixed at 1. Router Mode The available settings for router mode are as follows: Disabled —...
  • Page 92 RIP-2 updates. RIPv1OrRIPv2 – Both RIP-1 and RIP-2 route information can be received by the Switch. doNotSend – The Switch will not broadcast (or advertise) RIP updates. doNotReceive – The Switch does not process (or passively learn) incoming RIP packets.

  • Page 93: User Datagram Protocol (Udp) Helper

    RIP-2 can do this because it includes a subnet mask in its header. If your Switch receives a RIP-2 packet, it puts the route into the routing table with the subnet mask that was advertised.

  • Page 94: Implementing Udp Helper

    IP addresses to make routing decisions while it uses MAC addresses to forward packets from one hop to the next. You do not need to implement ARP — the Switch has ARP capability built in, but you can change and display the contents of the ARP cache.
  • Page 95 Figure 25 Example of an ARP Cache ARP cache IP address 158.101.1.1 158.101.2.1 If the IP address does not have a corresponding MAC address, the host or router broadcasts an ARP request packet to all the devices on the network. The ARP request contains information about the target and source addresses for the protocol (IP addresses).

  • Page 96: Arp Proxy

    When ARP proxy is enabled and a workstation sends an ARP request for a remote network, the Switch determines if it has the best route and then answers the ARP request by sending its own MAC address to the workstation.

  • Page 97: Internet Control Message Protocol (Icmp)

    With ICMP, you can determine whether a delivery failure resulted from a local or a remote problem. Advanced IP Your Switch has several features which further extend the networking Routing Options capabilities of the device. Refer to the following: 158.101.1.2...
  • Page 98 11: IP R HAPTER OUTING...

  • Page 99: Configuration Rules For Gigabit Ethernet

    Configuration Rules Gigabit Ethernet is designed to run over several media: for Gigabit Ethernet The different types of Gigabit Ethernet media and their specifications are detailed in Table 8 Gigabit Ethernet cabling ONFIGURATION Single-mode fiber optic cable, with connections up to 5 km (3.1 miles).

  • Page 100: Configuration Rules For Fast Ethernet

    The key topology rules are: ULES Figure 29 Maximum UTP cable length is 100 m (328 ft) over Category 5 cable. A 412 m (1352 ft) fiber link is allowed for connecting switch-to-switch, or endstation-to-switch, using half-duplex 100BASE-FX. illustrates the key topology rules...

  • Page 101: Configuration Rules With Full Duplex

    (one hub stack per wiring closet with a fiber link to the collapsed backbone). For example, a 225 m (738 ft) fiber link from a repeater to a router or switch, plus a 100 m (328 ft) UTP link from a repeater out to the endstations.

  • Page 102: Appendix A: Configuration

    A: C PPENDIX ONFIGURATION ULES...

  • Page 103: Network Configuration Examples

    ETWORK XAMPLES This chapter contains the following sections: Simple Network Configuration Example Advanced Network Configuration Example ONFIGURATION Desktop Switch Example Edge Switch Example...

  • Page 104: Appendix B: Network Configuration

    It illustrates the use of VLANs to separate an area of the network and the use of an aggregated link to increase the bandwidth on key links in your network. Figure 30 Using the Switch 3226 and Switch 3250 in a desktop environment XAMPLES Figure 30...

  • Page 105: Advanced Network Configuration Example

    Edge Switch Example The example in edge switch in a large network. It shows how you can use aggregated links to increase the bandwidth to your core network. In this network, end-to-end security can be implemented using a VLAN architecture and core traffic reduced by using Layer 3 switching at the edge.
  • Page 106 B: N PPENDIX ETWORK ONFIGURATION XAMPLES...

  • Page 107: Ip Addressing

    0 and 255. An example IP address is ‘192.168.100.8’. The IP address can be split into two parts: If your network is internal to your organization only, you may use any arbitrary IP address. 3Com suggests you use addresses in the series DDRESSING IP Addresses...

  • Page 108: Advanced Overview

    C: IP A PPENDIX DDRESSING 192.168.100.X (where X is a number between 1 and 254) with a subnet mask 255.255.255.0. These suggested IP addresses are part of a group of IP addresses that have been set aside specially for use “in house” only. CAUTION: If your network has a connection to the external IP network, you must apply for a registered IP address.
  • Page 109 referred to as a field or an octet. Decimal notation converts the value of each field into a decimal number, and the fields are separated by dots. Figure 33 Dotted Decimal Notation for IP Addresses 10011110.01100101.00001010.00100000 The decimal value of an octet whose bits are all 1s is 255. Network Portion The location of the boundary between the network part and the host part depends on the class that the central agency assigns to your...

  • Page 110: Subnets And Subnet Masks

    C: IP A PPENDIX DDRESSING Subnets and Subnet You can divide your IP network into sub-networks also known as subnets. Masks Support for subnets is important because the number of bits assigned to the device part of an IP address limits the number of devices that may be addressed on any given network.
  • Page 111 Subnets and Subnet Masks As shown in this example, the 32 bits of an IP address and subnet mask are usually written using an integer shorthand. This notation translates four consecutive 8-bit groups (octets) into four integers that range from 0 through 255.

  • Page 112: Default Gateways

    If manually configuring IP information for the Switch, enter the IP address of the default gateway on the local subnet in which the Switch is located. If no default gateway exists on your network, enter the IP address 0.0.0.0 Standard Mask Notation 100.100.100.100 (255.0.0.0)

  • Page 113: Advanced Ip Routing

    This chapter provides some additional background detail on the IP information that can be assigned to your Switch to enable you to manage it across a network. These are advanced features and are not required for operating your switch in your network. The topics covered are:...

  • Page 114: Supernetting

    D: A IP R PPENDIX DVANCED maintenance and the risk of creating erroneous addresses unless you plan the addressing scheme properly. Guidelines for Using VLSMs Consider the following guidelines when you implement VLSMs: See RFCs 1219 and 1878 for information about understanding and using VLSMs.
  • Page 115 routing table entry. (See RFC 1519 for detailed information about Supernetting.) To do this, supernet addressing does something very different from traditional TCP/IP routing (which allows only one netmask per network). In supernet routing, each supernet can be assigned its own netmask. Since supernet addressing is a fairly complex mechanism, the easiest way to understand it is to step through the setup process.
  • Page 116 D: A IP R PPENDIX DVANCED OUTING ONCEPTS supernet twice as large. So, a supernet composed of 8 Class C networks would actually have 3 zeroes (8 = 2 This would seem very limited since it restricts you to using groups that nicely fit into a power of 2 (1, 2, 4, 8, 16...).
  • Page 117 Figure 37 Selecting a Range of Addresses 11111100 255.255.252.0 Netmask Supernet Example The four networks in service provider (ISP). The ISP has decided to use supernetting to reduce the size of the routing tables and improve throughput. Figure 38 Supernet example Supernet 1 Network 234.170.160.0...
  • Page 118 D: A IP R PPENDIX DVANCED Now, assign ranges of addresses. Assume that the ISP is responsible for the network 234.170.0.0 and that its first free addresses are at 234.170.158.0. The third octet of Supernet 1 has to be an even multiple of 4, so the ISP grants an address range starting at 234.170.160.0 and hopes that the block between 158 and 160 can be filled in later.

  • Page 119: Glossary

    LOSSARY 3Com Network The 3Com network management application used to manage 3Com’s Supervisor networking solutions. 10BASE-T The IEEE specification for 10 Mbps Ethernet over Category 3, 4 or 5 twisted pair cable. 100BASE-FX The IEEE specification for 100 Mbps Fast Ethernet over fiber-optic cable.
  • Page 120 LOSSARY bandwidth The information capacity, measured in bits per second, that a channel can transmit. The bandwidth of Ethernet is 10 Mbps, the bandwidth of Fast Ethernet is 100 Mbps, and the bandwidth of Gigabit Ethernet is 1000 Mbps. baud The signalling rate of a line, that is, the number of transitions (voltage or frequency changes) made per second.

  • Page 121: Digital Certificate

    A mechanism that prevents packet loss during periods of congestion on the network. Packet loss is caused when devices send traffic to an already overloaded port on a Switch. Flow control prevents packet loss by inhibiting devices from generating more traffic until the period of...
  • Page 122 LOSSARY File Transfer Protocol. A protocol based on TCP/IP for reliable file transfer. full duplex A system that allows packets to be transmitted and received at the same time and, in effect, doubles the potential throughput of a link. gateway See router.

  • Page 123: Igmp Snooping

    IGMP snooping A mechanism performed by an intermediate device, such as a Layer 2 Switch, that optimizes the flow of multicast traffic. The device listens for IGMP messages and build mapping tables and associated forwarding filters, in addition to reducing the IGMP protocol traffic.
  • Page 124 Management Information Base. A collection of information about the management characteristics and parameters of a networking device. MIBs are used by the Simple Network Management Protocol (SNMP) to gather information about the devices on a network. The Switch contains its own internal MIB.
  • Page 125 Open Shortest Path First. A hierarchical Interior Gateway Protocol (IGP) routing algorithm. POST Power On Self Test. An internal test that a Switch carries out when it is powered-up. protocol A set of rules for communication between devices on a network. The rules dictate format, timing, sequencing and error control.
  • Page 126 See SSL. segment A section of a LAN that is connected to the rest of the network using a switch or bridge. server A computer in a network that is shared by multiple endstations. Servers provide endstations with access to shared network services such as computer files and printer queues.
  • Page 127 LANs than a bridge and are generally more sophisticated. Switch Database A database that is stored by a switch to determine if a packet should be forwarded, and which port should forward the packet if it is to be forwarded.

  • Page 128: Vlan Tagging

    LOSSARY unicast A packet sent to a single endstation on a network. Variable Length A suffix to an IP address that indicates the size of the subnet that Subnet Mask (VLSM) contains it. Taking the address 192.168.1.1/24 as an example, the VLSM is /24 and indicates that the first 24 bits of the address form the network part of the address.
  • Page 129 NDEX Numbers 802.1D priority levels 48 traffic classification 48 Access Control Lists 73 addresses classes 109 IP 88, 107 advertise RIP mode 91 advertisement address 93 aggregated links 14, 23 aging time, definition 46 alarm events 58 Alarms (RMON group) 56, 57 ARP (Address Resolution Protocol) cache 89, 94 defined 94...
  • Page 130 NDEX ICMP (Internet Control Message Protocol) description 97 location in OSI Reference Model 83 IEEE Std 802.1Q-1998 61 IEEE Std 802.3-2002 flow control 15, 22 IGMP multicast filtering 31 index, VLAN interface 88 interfaces IP 89 Internet addresses 107 InterNIC 108 IP (Internet Protocol) addresses 88, 108 interfaces 89...
  • Page 131 85 dynamic routes 86 metric 85 static routes 86, 89 status 85 Save 15 SDB. See Switch Database security network 71 segment, maximum length 100 segmentation, network 84 Spanning Tree Protocol, see STP 35 static route, IP 86, 90...
  • Page 132 NDEX...

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