RE: multicast on nbma network

From: Muthu (muthumon@xxxxxxx)
Date: Thu Sep 07 2000 - 22:33:32 GMT-3


   
Hi all,

I would appreciate if some body could clarify some questions regarding
this:Assume that I have full ip connectivity in the frame cloud ( from spoke
to spoke as well ).

1)do you meant to say that "ip pim nbma-mode" is necessary only in hub router.

What about in spoke routers ???

2) Did you configure <rp-address > in both the non-rp routers ( ie r2 and R3
)

3) Is there any restriction like rp router should be hub router ??

I was facing problem with this when I configured "ip pim nbma mode" on both
spokeas and hub routers.

Another query is there any restriction like rp router should be the hub router
??

Thanks
muthu

-----Original Message-----
From: Goh, Winston [mailto:winston.goh@sg.unisys.com]
Sent: Wednesday, June 07, 2000 7:35 PM
To: 'xuping'; ccielab@groupstudy.com
Subject: RE: multicast on nbma network

Hi,
i tried this scenario out before :
r1-----Frame relay------r2
               |
             |
            r3
configuring igmp join on r1 and r2 ethernet interfaces. Running ip pim
sparse on all routers, the non-broadcast nature of Frame-relay hinder r1 to
ping r2 multicast address and vice versa. Since r3 is the hub router,
configure ip pim nbma-mode and configure rp-address (r1). with this, i
manage to ping from spoke to spoke.
Alternatively, i tried ip pim sparse-dense mode without any ip pim nbma-mode
configuration. This seems to solve the problem as well. cheers
p/s : but i do notice that sometime i need to ping to the interface address
first before my multicast ping can get through.

Winston Goh
CCNP, CVE
Snr Network Specialist
Unisys Singapore
mobile : 97469192

-----Original Message-----
From: xuping [mailto:cnmiecxu@public.bta.net.cn]
Sent: Tuesday, June 06, 2000 6:09 PM
To: ccielab@groupstudy.com
Subject: multicast on nbma network

Hi

This question puzzle me for a long time.

Multicast routing is base on a tree (source tree or share tree), it meams
that a multicast router will not send out a multicast packet to an interface
on which it receive this packet. On a non-full mesh hub-spoke nbma network,
however, the hub router need send out multicast packet from one spoke to an
other. Without using sub-interface, the spoke router will only seen the hub
router as pim neighbor, the spoke to spoke neighbor relation will not
established.

Can I force the hub router relay the multicast packet from spoke1 to spoke2
just like a "no ip split-horizon"?

I check "ip pim nbma-mode" on DocCD, but it can't help.

If you read here, Thank you,
If you can give me a light, Thank you vvvvvery much!

xuping
cnmiecxu@public.bta.net.cn



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