Routing multicast address 224.0.0.251

jinestrosa · ‎05-21-2010

Hello

we would like to know if it's possible to route the multicast address 224.0.0.251 between VLAN?

Thanks for yours feedbacks

Mohamed Sobair · ‎05-21-2010

Yes its possible if you have multicast routing enabled between Vlans and Pim for example.

HTH

Mohamed

Giuseppe Larosa · ‎05-21-2010

Hello Jose,

short answer no: you cannot route addresses in block 224.0.0.x between different IP subnets they are reserved for link local scope and they cannot be routed, usually a packet with destination 224.0.0.x should also have IP TTL = 1 in IPv4 header.

For this reason for example auto-RP well known MAC addresses are 224.0.1.39 and 224.0.1.40 they need to be able to travel over multiple router hops.

Routing protocol hello messages use addresses like 224.0.0.X

224.0.0.5-224.0.0.6 is used by OSPF

224.0.0.9 by RIPv2

224.0.0.10 by EIGRP

224.0.0.13 by PIM

and so on these messages are link local confined to the Lan segment where they are generated

Hope to help

Giuseppe

Amanuddin Shaikh · ‎12-06-2012

Hi Giuseppe,

I am trying to communicate two vm machines resides in same VLAN over the same multicast address 224.0.0.251. This is an Oracle HeartBeat utility. It works on the same multicast address. Showing me error failed to communicate.

Please advise if I have to configure anything on Nexus 1000v for multicast.

Regards,

Aman

Mohamed Sobair · ‎05-21-2010

Jose,

Gui is correct, I didnt notice the multicast range you wrote.

The range: 224.0.0.0/24 is all reserved and have link local scope with TTL value of 1.

Regards,