All things related to multicast

["Kevin C. Almeroth" <>]

Date: Tue, 12 Nov 2002 12:36:35 -0500
From: Matthew Davy 
<>
To: Marshall Eubanks 
<>
Cc: Arturo Lev Servin 
<>,
 

Subject: Re: International Multicast

I've been looking at a potential multicast rpf problem on the Abilene <> GEANT
peering, but it's still not clear to me this is causing a problem.   
Specifically, the NEXT_HOP for all the NLRI=multicast routes we receive from
GEANT is set to 0.0.0.0.   This is mostly like caused by one of the Cisco,
Juniper MBGP interoperability bugs.   I'm debugging MSDP right now to see if 
this is causing us to RPF fail on their MSDP SAs...

- Matt





On Tue, Nov 12, 2002 at 12:28:08PM -0500, Marshall Eubanks wrote:
> We (AS 16517) see the source ip address
> 
> multicasttech-1>show ip mbgp 193.146.115.212
> BGP routing table entry for 193.144.0.0/14, version 25156
> Paths: (2 available, best #2, table NULL)
> Flag: 0x208
>   Advertised to non peer-group peers:
>   63.251.101.52
>   1239 11537 20965 766
>     160.81.38.225 from 160.81.38.225 (144.228.242.54)
>       Origin IGP, metric 116, localpref 100, valid, external
>   145 11537 20965 766
>     0.0.0.0 from 166.61.8.89 (204.147.128.136)
>       Origin IGP, localpref 100, valid, external, best
>       Community: 9503719 756091333 1373962395 1373969300
> 
> 
> but not the msdp SA's
> 
> multicasttech-1>show ip msdp sa | include 227.142.142.3
> multicasttech-1>
> 
> and mtrace is not very happy
> 
> multicasttech-1>mtrace
> Source address or name: 193.146.115.212
> Destination address or name: 63.105.122.133
> Group address or name: 227.142.142.3
> Multicast request TTL [64]:
> Response address for mtrace:
> Type escape sequence to abort.
> Mtrace from 193.146.115.212 to 63.105.122.133 via group 227.142.142.3
> From source (?) to destination (off-mct2.multicasttech.com)
> Querying full reverse path... * switching to hop-by-hop:
>  0  off-mct2.multicasttech.com (63.105.122.133)
> -1  * * * Timed out receiving responses
> Perhaps no local router has a route for source, the receiver is not
> a member of the multicast group or the multicast ttl is too low.
> 
> multicasttech-1>
> 
> 
> However, we do see _some_ msdp SA's from AS 766, as does Nordunet
> 
> http://www.nordu.net/connectivity/looking-glass/lg.cgi
> 
> So, it doubtful that you have a msdp black hole. Are you sure that the
> multicasts are actually being sourced at the present time ? Let me know
> when you are sure they are being sourced, and we will try and get them here.
> 
> It would be useful if the multicast beacon could be brought up at both
> AS 766 and at your location.
> 
> http://dast.nlanr.net/Projects/beacon/
> 
> Regards
> Marshall Eubanks
> 
> Arturo Lev Servin wrote:
> >Hi,
> >
> >    We are supposed (Tec de Monterrey, Mexico) to recieve a multicast 
> >session from Spain. In Spain they recieve the multicast session with out 
> >problem between the Spanish Universitues. In Mexico I can see and 
> >recieve the session from Oregon for example, but not from the Spanish.
> >
> >    I suppose that there is not multicast connectivity between Geant and 
> >Iris (European and Spainish networks) or between Abilene and Geant.
> >
> >    Any body knows if between Abilene and Geant exist multicast 
> >connectivity?
> >
> >    The multicast group they gave me is: (193.146.115.212, 227.142.142.3)
> >
> >    Another thing is that we have asymetric path in unicast. My unicast 
> >traffic goes from CUDI (Mexico) to VBNs to Abilene to geant. From Spain 
> >they go to Geant to Abilene and then directly to CUDI without passing 
> >VBNs. Could be this asymetric path another problem?
> >
> >Thanks in advance,
> >-as
> >
> 
> 
> -- 
>                                  Regards
>                                  Marshall Eubanks
> 
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> Multicast Technologies, Inc
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> Fairfax, Virginia 22030
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