Allied Telesis AR400 manual Static IGMP, Example, Page 48 AlliedWare OS How To Note IGMP

Static IGMP > Example

Static IGMP

Static IGMP enables you to configure a switch with specified group-to-interface or group-to- port mappings, which you may want to do if:

zyour network includes hosts that cannot send IGMP Membership Reports

zyou need to guarantee that a specific multicast stream is instantly available on a port, without any delay from the joining process

A common usage of Static IGMP is for protocols like Service Location Protocol (SLP). This protocol sends out multicast packets that need to be forwarded to designated ports. You may want SLP packets to be forwarded to ports that have servers who need to respond to these packets. Static IGMP allows you to specify that traffic for this group should go to hosts who will respond to, or are interested in, these messages. For detailed information about using Static IGMP and SLP, see How to configure IGMP snooping with unregistered multicast addresses such as Service Location Protocol (SLP) in the Allied Telesis website’s Technical Library.

Static IGMP is available on all the Allied Telesis managed layer 3 switches listed on page 3.

Example

In this example, we will start by setting an IGMP static entry for the group 224.12.13.14 to go to port 5 on switch 1 (part of vlan100). On that port we have attached a host which has no multicast client software running. After examining the effect of static IGMP on switch 1, we will add a static IGMP entry to switch 3 and consider the effect this has on multicasting through the network.

The network for this example has three switches in a loop and is shown in the following figure.

	Static client
	port 5
Multicast Server		AT-8948	Switch 1:
	port 1		Querier
	port 50	port 49
	(blocked by STP)
	port 26		port 26
Switch 2:	Rapier 24i		Rapier 24i	Switch 3
Snooper	port 25		port 25
			port 5
			Static client
			(added later in example)
				igmp-static.eps

Page 48 AlliedWare™ OS How To Note: IGMP