HP 2920 Series Multicast And Routing Manual
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HP 2920 Series Multicast And Routing Manual

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HP Switch Software
Multicast and Routing Guide for WB.15.16
Abstract
This switch software guide is intended for network administrators and support personnel, and applies to the switch models
listed on this page unless otherwise noted. This guide does not provide information about upgrading or replacing switch
hardware. The information in this guide is subject to change without notice.
Applicable Products
HP Switch 2920-series:
J9726A
J9727A
J9728A
J9729A
HP Part Number: 5998-6867
Published: October 2014
Edition: 1

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  • Page 1 This guide does not provide information about upgrading or replacing switch hardware. The information in this guide is subject to change without notice. Applicable Products HP Switch 2920-series: J9726A J9727A J9728A J9729A HP Part Number: 5998-6867 Published: October 2014 Edition: 1...
  • Page 2 The information contained herein is subject to change without notice. The only warranties for HP products and services are set forth in the express warranty statements accompanying such products and services. Nothing herein should be construed as constituting an additional warranty. HP shall not be liable for technical or editorial errors or omissions contained herein.

  • Page 3: Table Of Contents

    Contents 1 Multimedia Traffic Control with IP Multicast (IGMP).........7 Overview..........................7 IGMP general operation and features..................7 IGMP operating features.......................7 Basic operation.......................7 Enhancements........................7 Number of IP multicast addresses allowed................8 Configuring and displaying IGMP (CLI)..................8 Viewing IGMP configuration for VLANs..................8 Viewing the current IGMP configuration..................9 Viewing IGMP high level statistics for all VLANs on the switch..........10 Viewing IGMP historical counters for a VLAN................11 Viewing IGMP group address information................11...
  • Page 4 Configuring Static Multicast Groups.................28 Show Commands.......................28 Viewing the current IGMP configuration and status............28 Statistics and State commands.....................31 Help function commands......................32 3 IP Routing Features...................36 Overview..........................36 IP interfaces........................36 IP tables and caches......................36 ARP cache table......................36 ARP cache.......................37 IP route table........................37 Routing paths......................37 Administrative distance.....................37 IP forwarding cache......................37 IP route exchange protocols....................38...
  • Page 5 Defining RIP redistribution filters..................54 Configuring for redistribution..................55 Modifying default metric for redistribution.................55 Enabling RIP route redistribution..................55 Changing the route loop prevention method................56 Viewing RIP information......................56 Viewing general RIP information..................56 Viewing RIP interface information..................58 Viewing RIP peer information..................59 Viewing RIP redistribution information................60 Viewing RIP redistribution filter (restrict) information............60 Configuring IRDP........................60 Enabling IRDP globally.......................61...
  • Page 6 Messages related to UDP broadcast forwarding..............80 Index......................81 Contents...

  • Page 7: Multimedia Traffic Control With Ip Multicast (Igmp)

    NOTE: The use of static multicast filters is described in the chapter titled "Traffic/Security Filters" in the Access Security Guide for your HP switch. IGMP general operation and features In a network where IP multicast traffic is transmitted for various multimedia applications, you can use the switch to reduce unnecessary bandwidth usage on a per-port basis by configuring IGMP.

  • Page 8: Number Of Ip Multicast Addresses Allowed

    group. This means that IGMP traffic will be forwarded on a specific port only if an IGMP host or multicast router is connected to the port. Causes the switch to drop all IGMP transmissions received from a specific Blocked port. Outgoing queries are not blocked on the port. Causes the switch to forward all IGMP and IP multicast transmissions through Forward the port.

  • Page 9: Viewing The Current Igmp Configuration

    Example 1 Displaying IGMP status for a VLAN HP Switch(config)# show ip igmp vlan 1 IGMP Service Protocol Info Total VLANs with IGMP enabled : 30 Current count of multicast groups joined : 20 VLAN ID : 2 VLAN Name : VLAN2 IGMP version : 2 Querier Address : 10.255.128.2...

  • Page 10: Viewing Igmp High Level Statistics For All Vlans On The Switch

    The following version of the show ip igmp command includes the VLAN ID (vid) designation, and combines the above data with the IGMP per-port configuration: Example 3 Listing of IGMP configuration for a specific VLAN HP Switch(config)# show ip igmp vlan 2 config IGMP Service VLAN Config VLAN ID : 22...

  • Page 11: Viewing Igmp Historical Counters For A Vlan

    Viewing IGMP historical counters for a VLAN Syntax: show ip igmp vlan <vid> counters Example 5 Display of IGMP historical counters for a VLAN HP Switch(config)# show ip igmp vlan 1 counters IGMP service Vlan counters VLAN ID : 1 VLAN Name : DEFAULT_VLAN...

  • Page 12: Viewing Igmp Group Information For A Vlan With A Filtered Address

    Syntax: show ip igmp vlan <vid> group <ip-addr> Example 7 Group information for a VLAN with a filtered address group HP Switch(config)# show ip igmp vlan 22 group 239.20.255.7 IGMP Service Protocol Group Info VLAN ID: 22 VLAN NAME: VLAN-2 Filtered Group Address: 239.20.255.7...

  • Page 13: Configuring Per-Port Igmp Traffic Filters

    Depending on the privilege level, you could use one of the following commands to configure IGMP on VLAN 1 with the above settings: HP Switch(config)# vlan 1 ip igmp auto 1,2 forward 3,4 blocked 5,6 HP Switch(vlan-1)# ip igmp auto 1,2 forward 3,4...

  • Page 14: Configuring Static Multicast Groups

    Configuring static multicast groups Use this command to configure a group on the switch so that multicast traffic for that group can be forwarded with a receiver host. Traffic will be flooded for this group. Syntax: [no] ip igmp static-group <group-address> NOTE: This command must be issued in a VLAN context.

  • Page 15: Operation With Or Without Ip Addressing

    IGMP client on a port in the VLAN leaves the has an IP address and can operate as Querier. group. This can be a multicast router or another switch configured for IGMP operation. (HP Support Fast-Leave IGMP and Forced recommends that the VLAN also include a Fast-Leave IGMP (below.)
  • Page 16 Because of the multicast flooding problem mentioned above, the IGMP fast-leave feature is disabled by default on all HP switches that do not support data-driven IGMP (see the table above.) The feature can be enabled on these switches via an SNMP set of this object: hpSwitchIgmpPortForceLeaveState.<vid>.<port number>...

  • Page 17: Default (Enabled) Igmp Operation Solves The "Delayed Leave" Problem

    Figure 1 Example of automatic fast-leave IGMP criteria When client "3A" running IGMP is ready to leave the multicast group, it transmits a Leave Group message. Because the switch knows that there is only one end node on port A3, it removes the client from its IGMP table and halts multicast traffic (for that group) to port A3.

  • Page 18: Configuring Forced Fast-Leave Igmp

    Default: Disabled Example: To enable fastlearn on ports 5 and 6: HP Switch(config)# igmp fastlearn 5-6 Configuring delayed group flush When enabled, this feature continues to filter IGMP groups for a specified additional period of time after IGMP leaves have been sent. The delay in flushing the group filter prevents unregistered traffic from being forwarded by the server during the delay period.

  • Page 19: Igmp Proxy Forwarding

    IGMP proxy forwarding When a network has a border router connecting a PIM-SM domain to a PIM-DM domain, the routers that are completely within the PIM-DM domain have no way to discover multicast flows in the PIM-SM domain. When an IGMP join occurs on a router entirely within the PIM-DM domain for a flow that originates within the PIM-SM domain, it is never forwarded to the PIM-SM domain.

  • Page 20: Configuring Igmp Proxy (Cli)

    IGMP proxy border IP addrses (1 1 1.1 1.1 1 1.1 1 1) being configured. Example 10 IGMP proxy border IP address command HP Switch(config)# igmp-proxy-domain Bob 111.11.111.111 Example 1 1 shows the lower and upper boundaries of the multicast address range associated with the domain named Bob.

  • Page 21: Vlan Context Command

    Example 1 1 Setting the lower and upper bounds for multicasting HP Switch(config)# igmp-proxy-domain Bob 111.11.111.111 234.0.0.1 HP Switch(config)# igmp-proxy-domain Bob 111.11.111.111 236.1.1.1 VLAN context command This command is performed when in VLAN context mode. When a query occurs on the upstream interface, an IGMP join is sent for all multicast addresses that are currently joined on the downstream interface.

  • Page 22: Operating Notes For Igmp Proxy Forwarding

    Example 12 Showing active IGMP proxy entries HP Switch(config)# show igmp-proxy entries Total number of multicast routes: 2 Multicast Address Border Address Multicast Domain ----------------- -------------- ----- ------ 234.43.209.12 192.168.1.1 George 235.22.22.12 15.43.209.1 226.44.3.3 192.168.1.1 George Example 13 Showing IGMP proxy domains...

  • Page 23: Using The Switch As Querier

    You must remove all VLAN associations with the domain name before that domain name can be removed. The appropriate border routers must be used for each VLAN, or PIM-DM will not forward the traffic. This could occur when multiple border routers exist. It may be necessary to configure multiple overlapping domains if the multicast source address can generate the same multicast address and have different best paths to the PIM-DM domain.

  • Page 24: Well-Known Or Reserved Multicast Addresses Excluded From Ip Multicast Filtering

    IP multicast filters NOTE: This operation applies to the HP Series 5400zl switches, the Series 3500yl switches, the switch 6200yl, the switch 8212zl, the Series 5300xl switches, as well as the 1600M, 2400M, 2424M, 4000M, and 8000M, but not to the Series 2500, 2650, Series 4100gl, Series 4200vl, or 6108 switches (which do not have static traffic/security filters.)

  • Page 25: Reserved Addresses Excluded From Ip Multicast Filtering

    "multicast address" in this range, the switch will use the static filter unless IGMP learns of a multicast group destination in this range. In this case, IGMP dynamically takes over the filtering function for the multicast destination addresses for as long as the IGMP group is active. If the IGMP group subsequently deactivates, the switch returns filtering control to the static filter.

  • Page 26: Multimedia Traffic Control With Ip Multicast (Igmp) V2 Ng

    2 Multimedia Traffic Control with IP Multicast (IGMP) v2 IGMP V2 NG Overview IGMP, after being re-architected, is referred to as IGMP v2 NG, the next generation of IGMP version 2. IGMP v2 NG is based on the existing working Multicast Listener Discovery (MLD) code base and an event-driven architecture which enable easy enhancement and maintenance of the code.

  • Page 27: Configuring Fast-Learn Igmp

    Syntax: igmp delayed-flush <0-255> Configuring Fast-Learn IGMP Enables the fast learn feature globally. The no form of the command disables the fast learn feature. This command is independent of interface context fast-learn command and only one command will be exposed to the user. By default, this feature is disabled on all ports. hpicfIgmpMcastPortFastLearn is the Mib variable defined for this command.

  • Page 28: Configuring Fast-Leave Igmp

    Configuring Fast-Leave IGMP Enables igmp fast-leaves on the specified ports in the selected VLAN. The no form of the command disables igmp fast-leave on the specified ports in the selected VLAN. (Default: Enabled.) Syntax: [no] vlan <vid> ip igmp fastleave <port-list> Configuring Forced Fast-Leave IGMP Enables IGMP Forced Fast-Leave on the specified ports in the selected VLAN, even if they are cascaded.
  • Page 29 xxx.xxx.xxx.xxx |std | 3min 2sec | all xxx.xxx.xxx.xxx |filt| 23min 3sec | A1-B3, C4 xxx.xxx.xxx.xxx |filt| 23min 10sec| A1,B2,C5 xxx.xxx.xxx.xxx |filt| 2min 5sec | F22 VLAN ID: VLAN Name: client vlan IGMP Version: 2 Querier Address: 10.0.102.204 Querier Port: 4 <only displayed when not querier> Querier Up Time: 1hr 53min 2sec Querier Expiry Time:...
  • Page 30 Displays IGMP configuration for a specific VLAN on the switch, including per-port data. IGMP Service Vlan Config VLAN ID: VLAN NAME: VLAN300 IGMP Enabled [No]: Querier Allowed [Yes]: Yes Port| Type | Port Mode | Forced Fast Leave | Fast Leave----+---------------+ ----------+-------------------+----------------- |100/1000T Auto...

  • Page 31: Statistics And State Commands

    ------- ------------- --------------- --------------- --------------- + ------ 226.0.6.7 0h 2m 58s 1h 13m 4s 192.168.0.2 | Filter 226.0.6.8 0h 2m 58s 1h 13m 4s 192.168.0.2 | Standard 226.0.6.9 0h 2m 58s 1h 13m 4s 192.168.0.2 | Static Statistics and State commands Syntax: show ip igmp statistics Displays IGMP high level statistics for all VLANs on the switch.

  • Page 32: Help Function Commands

    Help function commands Syntax: show igmp delayed-flush Shows switch-wide IGMP delayed flush value. Output: IGMP Delayed Group Flush Timer: Disabled Syntax: show igmp filter-unknown-mcast Shows switch-wide IGMP filter unknown multicast value. Output: IGMP Filter Unknown Multicast: Disabled IGMP Filter Unknown Multicast Status: Disabled Syntax: show ip igmp Usage:...
  • Page 33 Syntax: show ip igmp groups Shows VLAN-ID, uptime, expiration time, multicast filter type. Output: IGMP Group Address Information VLAN ID Group Address Expires UpTime Last Reporter | Type ------- ------------- --------- -------- --------------- + ----- Syntax: show ip igmp config Shows IGMP configuration information.
  • Page 34 The group keyword can be used to show a list of ports where a particular multicast group is registered. The group keyword can be used to show VLAN-ID, group address, uptime, expiration time, last reporter and hardware filter type information for each group. When followed by VLAN keyword and VLAN-ID, it displays the VLAN group address, uptime, expiration time, last reporter and multicast filter type for groups that belong to that VLAN-ID.
  • Page 35 Output: IGMP service Vlan counters VLAN ID : 5 VLAN Name : VLAN5 General Query Rx General Query Tx : 115 Group Specific Query Rx Group Specific Query Tx V1 Member Report Rx V2 Member Report Rx : 108 V3 Member Report Rx Leave Rx Unknown IGMP Type Rx Unknown Pkt Rx...

  • Page 36: Ip Routing Features

    SNMP access, as well as for routing. NOTE: All HP devices support configuration and display of IP address in classical subnet format (example: 192.168.1.1 255.255.255.0) and Classless Interdomain Routing (CIDR) format (example: 192.168.1.1/24.) You can use either format when configuring IP address information. IP addresses are displayed in classical subnet format only.

  • Page 37: Arp Cache

    To configure a static IP route, see “Configuring a static IP route” (page 47). IP forwarding cache The IP forwarding cache provides a fast-path mechanism for forwarding IP packets. The cache contains entries for IP destinations. When an HP routing switch has completed processing and Overview...

  • Page 38: Ip Route Exchange Protocols

    addressing for a packet and is ready to forward the packet, the device checks the IP forwarding cache for an entry to the packet's destination. If the cache contains an entry with the destination IP address, the device uses the information in the entry to forward the packet out the ports listed in the entry.
  • Page 39 Table 3 IP global parameters for routing switches (continued) Parameter Description Default See page a packet can pass before in the Management and being discarded. Each Configuration Guide. router decreases a packet's TTL by 1 before forwarding the packet. If decreasing the TTL causes the TTL to be 0, the router drops the packet instead of forwarding it.

  • Page 40: Arp Age Timer

    Default: 20 minutes Example 17 Setting the ARP age timeout to 1000 minutes HP Switch(config)# ip arp-age 1000 To view the value of ARP age timer, enter the show ip command. The Arp Age time value is shown in bold in...

  • Page 41: Ip Interface Parameters For Routing Switches

    Example 19 The ip arp-age value in the running config file HP Switch(config)# show running-config Running configuration: ; J9627A Configuration Editor; Created on release #XX.15.XX ; Ver #01:01:00 hostname "Switch" savepower led mirror-port 7 stack commander "TEST_STACK" stack member 1 mac-address 0024A8D13A40...

  • Page 42: Configuring Ip Parameters For Routing Switches

    Table 4 IP interface parameters — routing switches (continued) Parameter Description Default See page parameter applies only to RIP routes. ICMP Router Discovery Locally overrides the global Disabled Protocol (IRDP) IRDP settings. See Table 3 (page 38) for global IRDP information.

  • Page 43: Configuring Forwarding Parameters

    A MAC broadcast is not routed to other networks. However, some routers, including HP routing switches, can be configured to reply to ARP requests from one network on behalf of devices on another network.

  • Page 44: Enabling Forwarding Of Ip Directed Broadcasts (Cli)

    You can enable or disable ICMP address mask replies. Disabling replies to broadcast ping requests By default, HP devices are enabled to respond to broadcast ICMP echo packets, which are ping requests (for more information, see “Disabling ICMP messages” (page 44)).

  • Page 45: Disabling Icmp Destination Unreachable Messages

    The packet was dropped by the HP device due to a filter or ACL configured on the device. Fragmentation-needed The packet has the "Don't Fragment" bit set in the IP Flag field, but the HP device cannot forward the packet without fragmenting it.

  • Page 46: Static Route Types

    Static route types You can configure the following types of static IP routes: Standard The static route consists of a destination network address or host, a corresponding network mask, and the IP address of the next-hop IP address. Null (discard) The null route consists of the destination network address or host, a corresponding network mask, and either the reject or blackhole keyword.

  • Page 47: Configuring A Static Ip Route

    For example, the following command configures a static route to 207.95.7.0 (with a network mask of 255.255.255.0), using 207.95.6.157 as the next-hop router's IP address: HP Switch(config)# ip route 207.95.7.0/24 207.95.6.15 A static IP route specifies the route's destination address and the next-hop router's IP address or routing switch interface through which the routing switch can reach the destination.

  • Page 48: Viewing Static Route Information

    The following example configures two static routes for traffic delivery and identifies two other null routes for which traffic should be discarded instead of forwarded. Example 21 Configuring static routes HP Switch(config)# ip route 10.10.40.0/24 10.10.10.1 HP Switch(config)# ip route 10.10.50.128/27 10.10.10.1 HP Switch(config)# ip route 10.10.20.177/32 reject HP Switch(config)# ip route 10.10.30.0/24 blackhole...

  • Page 49: Configuring Ecmp Routing For Static Ip Routes

    Configuring ECMP routing for static IP routes IMPORTANT: This section applies to the HP Switch 2615-series (J9565A) and the HP Switch 2915-series (J9562A) only. ECMP routing allows multiple entries for routes to the same destination. Each path has the same cost as the other paths, but a different next-hop router.

  • Page 50: Configuring Rip

    Routing Information Protocol (RIP) is an IP route exchange protocol that uses a distance vector (a number representing distance) to measure the cost of a given route. The cost is a distance vector because the cost often is equivalent to the number of router hops between the HP routing switch and the destination network.

  • Page 51: Rip Parameters And Defaults

    HP routing switch's route table, the routing switch replaces the older route with the newer one. The routing switch then includes the new path in the updates it sends to other RIP routers, including HP routing switches.

  • Page 52: Configuring Rip Parameters

    RIP version is RIPv2-only. You can change the RIP version on an individual interface basis to RIPv1 or RIPv1-or-v2, if needed. To enable RIP on a routing switch, enter the following commands: HP Switch(config)# ip routing HP Switch(config)# router rip HP Switch(rip)# exit...

  • Page 53: Enabling Ip Rip On A Vlan

    Example 25 Enter RIP router context HP Switch(config)# router rip HP Switch(rip)# Example 26 Enable RIP routing HP Switch(config)# router rip enable HP Switch(rip)# Example 27 Disable RIP routing HP Switch(config)# router rip disable HP Switch(rip)#...

  • Page 54: Changing The Rip Type On A Vlan Interface

    To increase the cost a VLAN interface adds to RIP routes learned on that interface, enter commands such as the following: HP Switch(config)# vlan 1 HP Switch(vlan-1)# ip rip metric 5 These commands configure vlan- 1 to add 5 to the cost of each route learned on the interface. Syntax: ip rip metric <1-16>...

  • Page 55: Configuring For Redistribution

    To configure the switch to filter out redistribution of static or connected routes on network 10.0.0.0, enter the following commands: HP Switch(config)# router rip HP Switch(rip)# restrict 10.0.0.0 255.0.0.0 HP Switch(rip)# write memory The default configuration permits redistribution for all default connected routes only.

  • Page 56: Changing The Route Loop Prevention Method

    Split horizon. (Poison reverse is an extension of Split horizon.) To disable Poison reverse on an interface, and thereby enable Split horizon, enter the following: HP Switch(config)# vlan 1 HP Switch(vlan-1)# no ip rip poison-reverse Viewing RIP information All RIP configuration and status information is shown by the CLI command show ip rip and options off that command.
  • Page 57 Example 29 General RIP information listing HP Switch(config)# show ip rip RIP global parameters RIP protocol : enabled Auto-summary : enabled Default Metric : 1 Distance : 120 Route changes Queries RIP interface information IP Address Status Send mode Recv mode...

  • Page 58: Viewing Rip Interface Information

    To show the RIP interface information for VLAN 1000, use the show ip rip interface vlan <vid> command. Example 31 RIP interface output by VLAN HP Switch# show ip rip interface vlan 4 RIP configuration and statistics for VLAN 4 RIP interface information for 100.4.0.1 IP Address : 100.4.0.1...

  • Page 59: Viewing Rip Peer Information

    To show the RIP interface information for the interface with IP address 100.2.0.1, enter the show ip rip interface command: Example 32 The show IP rip interface output by IP address HP Switch# show ip rip interface 100.2.0.1 RIP interface information for 100.2.0.1 IP Address : 100.2.0.1...

  • Page 60: Viewing Rip Redistribution Information

    55)). Configuring IRDP The ICMP Router Discovery Protocol (IRDP) is used by HP routing switches to advertise the IP addresses of their router interfaces to directly attached hosts. IRDP is disabled by default. You can enable the feature on a global basis or on an individual VLAN interface basis.

  • Page 61: Enabling Irdp Globally

    IRDP is enabled on the HP routing switch, the routing switch responds to the Router Solicitation messages. Some clients interpret this response to mean that the routing switch is the default gateway. If another router is actually the default gateway for these clients, leave IRDP disabled on the HP routing switch.

  • Page 62: Viewing Irdp Information

    Syntax: [no] ip irdp [ broadcast | multicast ] [holdtime <seconds>] [maxadvertinterval <seconds>] [minadvertinterval <seconds>] [preference <number>] Specifies the packet type the routing switch uses to send the [broadcast | multicast] Router Advertisement: The routing switch sends Router Advertisements broadcast as IP broadcasts.

  • Page 63: Configuring Dhcp Relay

    IP parameters, communication between the client and server is by unicast packets. HP routing switches provide the DHCP relay agent to enable communication from a DHCP server to DHCP clients on subnets other than the one the server resides on. The DHCP relay agent transfers DHCP messages from DHCP clients located on a subnet without a DHCP server to other subnets.

  • Page 64: Prerequisites For Dhcp Relay Operation

    DHCP servers on other subnets. Enabling DHCP relay The DHCP relay function is enabled by default on an HP routing switch. However, if DHCP has been disabled, you can re-enable it by entering the following command at the global configuration...

  • Page 65: Viewing Dhcp Helper Addresses

    The vlan <vlan-id> parameter specifies a VLAN ID number. The following command lists the currently configured IP Helper addresses for VLAN 1. Example 39 Displaying IP helper addresses HP Switch(config)# show ip helper-address vlan 1 IP Helper Addresses IP Helper Address ----------------- 10.28.227.97...

  • Page 66: Option 82 Server Support

    The routing switch can operate as a DHCP relay agent to enable communication between a client and a DHCP server on a different subnet. Without Option 82, DHCP operation modifies client IP address request packets to the extent needed to forward the packets to a DHCP server. Option 82 enhances this operation by enabling the routing switch to append an Option 82 field to such client requests.

  • Page 67: General Dhcp Option 82 Requirements And Operation

    Figure 5 Example of a DHCP Option 82 application General DHCP Option 82 requirements and operation Requirements DHCP Option 82 operation is configured at the global config level and requires the following: IP routing enabled on the switch DHCP-relay option 82 enabled (global command level) Routing switch access to an Option 82 DHCP server on a different subnet than the clients requesting DHCP Option 82 support One IP helper address configured on each VLAN supporting DHCP clients...

  • Page 68: Option 82 Field Content

    Figure 6 Example of DHCP Option 82 operation in a network with a non-compliant relay agent Option 82 field content The remote ID and circuit ID subfields comprise the Option 82 field a relay agent appends to client requests. A DHCP server configured to apply a different IP addressing policy to different areas of a network uses the values in these subfields to determine which DHCP policy to apply to a given client request.

  • Page 69: Circuit Id

    Option 82 DHCP server to use the Circuit ID to select a DHCP policy to assign to clients connected to the port. This number is the identity of the inbound port. On HP fixed-port switches, the port number used for the circuit ID is always the same as the physical port number shown on the front of the switch.

  • Page 70: Forwarding Policies

    ID (port) associated with the remote ID (IP address) for the selected VLAN. Forwarding policies DHCP Option 82 on HP switches offers four forwarding policies, with an optional validation of server responses for three of the policy types (append, replace, or drop.)

  • Page 71: Multiple Option 82 Relay Agents In A Client Request Path

    Multiple Option 82 relay agents in a client request path Where the client is one router hop away from the DHCP server, only the Option 82 field from the first (and only) relay agent is used to determine the policy boundary for the server response. Where there are multiple Option 82 router hops between the client and the server, you can use different configuration options on different relay agents to achieve the results you want.

  • Page 72: Multinetted Vlans

    Server response validation is an option you can specify when configuring Option 82 DHCP for append, replace, or drop operation. See “Forwarding policies” (page 70). Enabling validation on the routing switch can enhance protection against DHCP server responses that are either from untrusted sources or are carrying invalid Option 82 information.

  • Page 73: Configuring Option 82

    server to support more narrowly defined DHCP policy boundaries instead of defining the boundaries at the VLAN or whole routing switch levels. If the MAC address option (the default) is configured instead, the routing switch MAC address will be used regardless of which subnet was the source of the client request.

  • Page 74: Example Of Option 82 Configuration

    Example of Option 82 configuration In the routing switch shown below, option 82 has been configured with mgmt-vlan for the remote HP Switch(config)# dhcp-relay option 82 append mgmt-vlan The resulting effect on DHCP operation for clients X, Y, and Z is shown in...

  • Page 75: Operating Notes

    Table 8 DHCP operation for the topology in Figure 10 Client Remote ID giaddr DHCP server 10.38.10.1 10.39.10.1 A only If a DHCP client is in the management VLAN, its DHCP requests can go only to a DHCP server that is also in the management VLAN.

  • Page 76: Udp Broadcast Forwarding

    If the Management VLAN IP address configuration changes after mgmt-vlan has been configured as the remote ID suboption, the routing switch dynamically adjusts to the new IP addressing for all future DHCP requests. The Management VLAN and all other VLANs on the routing switch use the same MAC address. UDP broadcast forwarding Overview Some applications rely on client requests sent as limited IP broadcasts addressed to a UDP...

  • Page 77: Subnet Masking For Udp Forwarding Addresses

    Table 9 Example of a UDP packet-forwarding environment (continued) Interface IP address Subnet mask Forwarding Notes address port unicast forwarding address configured in VLAN 1 must be on this VLAN. Also the destination VLAN for UDP 1812 from clients on VLAN 1. VLAN 3 15.75.12.1 255.255.255.0...

  • Page 78: Viewing The Current Ip Forward-Protocol Configuration

    Example: The following command configures the routing switch to forward UDP broadcasts from a client on VLAN 1 for a time protocol server: HP Switch(vlan-1)# ip forward-protocol udp 15.75.11.155 timep Viewing the current IP forward-protocol configuration Syntax: show ip forward-protocol [vlan <vid>] Displays the current status of UDP broadcast forwarding and lists the UDP forwarding addresses configured on all static VLANS in the switch or on a specific VLAN.

  • Page 79: Operating Notes For Udp Broadcast Forwarding

    UDP broadcast forwarding status and the configured forwarding addresses for inbound UDP broadcast traffic on VLAN 1. Example 43 Displaying IP forward-protocol status and per-VLAN configuration HP Switch(config)# show ip forward-protocol vlan 1 IP Forwarder Addresses UDP Broadcast Forwarding: Disabled...
  • Page 80 Port Numbers Messages related to UDP broadcast forwarding Message Meaning Appears in the CLI if an attempt to enable UDP broadcast forwarding has been udp-bcast-forward: IP Routing support must be made without IP routing being enabled first. Enable IP routing, then enable UDP enabled first.
  • Page 81 Index ip igmp statistics, ip igmp vlan, 9, ip rip, cache table, ip rip interface, configuring parameters, show igmp delayed-flush, how it works, show igmp filter-unknown-mcast, auto port setting, show ip igmp, show ip igmp config, 29, show ip igmp groups, 30, blocked port show ip igmp statistics, 31, from IGMP operation,...
  • Page 82 parameter configuring;configuration:IP routing parameters, helper address for DHCP Relay, route exchange protocols, routing table, static route configuration, IANA, static route parameters, ICMP static route types, configuring, static routes disabling messages, discard traffic, IGMP discard, ICMP notification, benefits, tables and caches, effect on filters, VLAN interface Exclude Source,...
  • Page 83 changing cost of RIP routes, VLAN, subnetted, changing RIP type, changing the RIP metric, configuring, VLAN displaying configuration and status, IGMP configuration;IGMP:configure per VLAN, displaying general information, VLAN interface displaying information, IP routing parameters, displaying interface information, displaying peer information, displaying redistribution information, displaying restrict information, enabling globally,...

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