Configuring IGMP Proxy

This chapter describes how to configure the Internet Group Management Protocol (IGMP) proxy.

Understanding IGMP Proxy

The purpose of IGMP proxy is to enable a multicast router to learn multicast group membership information and be able to forward multicast packets based upon the group membership information. The IGMP Proxy is capable of functioning only in certain topologies that does not require Multicast Routing Protocols (i.e. DVMRP, PIM-DM, and PIM-SM) and have a tree-like topology, as there is no support for features like spanning tree to correct packet route loops.

The proxy contains many downstream interfaces and a unique upstream interface explicitly configured. It performs the host side of the IGMP protocol on its upstream interface and the router side of the IGMP protocol on its downstream interfaces.

The IGMP proxy offers a mechanism for multicast forwarding based only upon IGMP membership information. The router has to decide about forwarding packets on each of its interfaces based on the IGMP membership information. The proxy creates the forwarding entries based on the membership information and adds it to the multicast forwarding cache (MFC) in order not to make the forwarding decision for subsequent multicast packets with same combination of source and group.

Configuring IGMP Proxy via CLI

The CLI component of FASTPATH allows the end users to configure the network device and to view device settings and statistics using a serial interface or telnet session.

Example 1: Configuring the Interface

This command enables the IGMP Proxy on the router. To enable IGMP Proxy on the router no multicast routing protocol should be enabled and also multicast forwarding must be enabled on the router. Use this command from the CLI mode.

CODE EXAMPLE 20-1 Configuring the Interface
(DTI SWITCH) (Interface 0/15)# ip igmp-proxy ? <cr> Press Enter to execute the command. reset-status Reset All the proxy interface status parameters. unsolicited-report-interval Configure IGMP Proxy unsolicited report interval.

CODE EXAMPLE 20-1 Configuring the Interface

(DTI SWITCH) (Interface 0/15)# ip igmp-proxy ?
 
<cr> Press Enter to execute the command.
reset-status Reset All the proxy interface status parameters.
unsolicited-report-interval Configure IGMP Proxy unsolicited report interval.

Example 2: Set the Unsolicited Report Interval

This command is valid only when IGMP Proxy is enabled on the interface. The value of <interval> could be in range of 1 to 260 seconds. The default is 1 second. Use this command from the Interface mode.

CODE EXAMPLE 20-2 Setting Unsolicited Report Interval
(DTI SWITCH) (Interface 0/15)# ip igmp-proxy unsolicited-report-interval ? <1-260> Enter unsolicited report interval in seconds.

Example 3: Reset the Host Interface Status Parameters

CODE EXAMPLE 20-3 Resetting Host Interface Status Parameters
(DTI SWITCH) (Interface 0/15)# ip igmp-proxy reset-status ? <cr> Press Enter to execute the command.

Example 4: Show IGMP Proxy Host Interfaces

This command displays a summary of the host interface status parameters. It displays the parameters only when IGMP Proxy is enabled. Use this command from Privileged EXEC or User EXEC modes.

CODE EXAMPLE 20-4 Showing IGMP Proxy Host Interfaces
(DTI SWITCH) # show ip igmp-proxy Admin Mode..................................... Enable Operational Mode............................... Disable

Example 5: Show Detailed Listing of Host Interface Status

This command displays parameters only when IGMP Proxy is enabled. Use the command from Privileged EXEC or User EXEC modes.

CODE EXAMPLE 20-5 Showing Host Interface Status
(DTI SWITCH) # show ip igmp-proxy interface

Example 6: Show IGMP Proxy Groups

Use this command to display information about multicast groups that IGMP proxy reported. It displays a table of entries with the following as the fields of each column. Use the command from Privileged EXEC or User EXEC modes.

CODE EXAMPLE 20-6 Showing IGMP Proxy Groups
(DTI SWITCH) # show ip-igmp-proxy groups

Example 7: Show Detailed Information about IGMP Proxy Groups

Use this command to display information about multicast groups that IGMP proxy reported. It displays a table of entries with the following as the fields of each column. Enter this command from Privileged EXEC or User EXEC modes.

CODE EXAMPLE 20-7 Showing Detailed Information About Proxy Groups
(DTI SWITCH) # show ip igmp-proxy groups detail