Example:
The unicast routing protocol in use on all connected routers is OSPF, and all ports are on the same VLAN. An endstation joins the IP multicast group 226.128.0.5 on port 1. The MAC address for the group is 01:00:5E:00:00:05. IGMP snooping creates a session for this MAC address, with port 1 as the client port. There is a
link scoped group 224.0.0.5, which also maps to a MAC address of 01:00:5E:00:00:05. Because port 2 is not considered a router port, and it is not part of the 01:00:5E:00:00:05 session, the switch only passes OSPF messages out port 1. Other protocols, such as the Service Location Protocol (RFC 2608), use 224.0.1.22 and 224.0.1.35, which can be blocked by endstations joining sessions that map to the same MAC address.
Note: This is the same problem that is discussed in the Microsoft
Product Support Article Q223136 that can be found at:
http://support.microsoft.com/support/kb/articles/Q223/1/ 36.asp
involving RRAS setup. This specific issue, however, should not break routing protocols as suggested in this article because the Cajun switch ignores joins for local multicast groups (224.0.0.x).
Workaround: Check that all ports that are connected to the router are configured as router ports. This prevents all
If other
Refer to the following web site for a complete list of internet multicast addresses recognized by the IANA:
Note: Enable is the default state for “Rate Limiting” on 10/100 Mbps ports. Multicast traffic and broadcast traffic is
Multicast traffic is
June 14, 2001 | 21 |
