flow & working of multicast:

[s4sandyad]

Hi,

Src Srv ---Core switch (sparse;RP) --- Multiple Border routers(for mpls, p2p,isdn) ; (static joing group.x.x.x.x )-----------isp-------------client end router-----client lan ---receiving feed anent.

Abover mentioned is generic multicast scenario where multicast source server is connected to core switch which is further connected to multiple border routers for each media segments (each for mpls, vsat, isdn, p2p etc). border routers connected to isp end as per their media type. isp then connected to client end router. which further connected to lan receiving agent.

i want to under stand complete flow of steps and packet flow; after receiving agent login into their application till it receive multicast feeds from source server.

like: first client will login in application; authentication will be checked with source ip of receiving agent with destination of source server.

then igmp request is generated by application agent; in that source will be the ip of agent what will be the destination ip or multicast group add.

how that request is forwarded to source through wan media; how RP will tackle it; 

can any one please tell me the end to end flow of packets...or suggest some good documents accordingly.

sandy

[chrihussey · Accepted solution]

Aside from how or why the source starts to generate the multicast, which is probably at the application level, from a network / routing perspective:

1- The source generates the multicast to its local segment and the PIM routers notify the RP of the active source.

2- The receiver sends an IGMP join for the group to its local segment and the PIM router notifies the RP. 

3- Via reverse path forwarding (using the routing table) connectivity is established from source to host through the RP.

4- Depending on how you have sparse mode configured, after a period of time the multicast flow transitions to the shortest path tree. Meaning if there is a better / shorter route between source and host, the stream will adjust to that.

Here are some documents:

http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti/config_library/15-s/imc-pim-15-s-book/imc_tech_oview.html#GUID-F6A7759F-29A2-4264-8031-7E50A10BBBD9

http://www.cisco.com/c/en/us/td/docs/ios/solutions_docs/ip_multicast/White_papers/mcst_ovr.html#wp1009081

Hope this helps

[s4sandyad]

Thanks chrihussey