Re: frame relay hub and spoke multicast

From: Victor Cappuccio (cvictor@protokolgroup.com)
Date: Sun Mar 26 2006 - 10:53:24 GMT-3


 Petr, thanks for the explanation, could you please go a little bit int
detail in points 1 and 2, when running pim sparse over H&S,
What if I'm not allowed to move the MA to another place? the ip mroute
will be sufficient??
and in point 2 I thought that the problem would be if Multicast Client
Router to the MAgent fails the RPF Check

Many Thanks
Victor.

Petr Lapukhov escribis:

  -- Sorry, repating e-mail to group address
  
  Hello David,
  
  If you run PIM Dense mode over FR H&S topology, you basically
  face an OLIST problem when you try to reach group joined on spoke
  from another spoke.
  
  Hub won't forward mpacket on the same interface it was received from.
  This problem could be solved with single tunnel (either R1-R2, R2-R3, R1-R3)
  
  and proper static mroute on _receiving_ side of the tunnel (to prefer tunnel
  over
  physical interface for sure).
  
  Now if you run PIM Sparse over H&S, you may face the same problem,
  and more.
  
  1) You may miss BSR/AutoRP announces due to OLIST problem.
  2) You may be unable to join shared tree if RP is places improperly (spoke)
  3) You may face OLIST problem with mpacket delivery (the same as above).
  
  Leaving 1,2 aside, lets look at 3.
  
  For that mpacket OLIST problem, you may basically:
  
  1) use tunnel/mroute, as in PIM-DM
  2) use "pim nbma-mode" on hub multipoint interface,
  3) enable PIM bidir mode to use bidirectional shared tree and place RP on
  hub
  
  HTH
  Petr
  
  2006/3/26, david robin <robindavi@gmail.com> :

    dear all,
    I want to very something with ip multicast, if we have a frame-relay
    connection, R1 is the hub connected wih a multipoint interface to r2 and
    r3
    the spokes, the qusetion is if we had a multicast group on r2 fast
    ethernet
    ( using ip igmp join), the fact that I cant ping this multicast group from
    r3, does i have to configure tunnels ( 1 tunnel between r1 and r2 and 1
    tunnel between r1 and r3) in order to make the multicast packets flow ??
    
    Also there is another question in case i run pim sparse-dense as r1 is the
    RR the same problem will occur and does i have to configure tunnel too ???
    
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