[Xorp-users] Fwd: how to forward a multicast message with pimsm?

Pavlin Radoslavov pavlin@icir.org
Wed, 09 Nov 2005 18:51:24 -0800


Hajni,

Your configuration looks fine.
However, for whatever reason Router2 hasn't sent PIM-SM Join message
toward Router1 (the RP).

Could you double-check that Host2 has really joined the multicast
group. On Router2 "show igmp group" inside xorpsh should show that
Host2 is a receiver.
If you don't see Host2 as a receiver, then on Host2 itself you could
run a command like "netstat -g" in case of FreeBSD to see the joined
multicast groups.
If, say, you see that Host2 has indeed joined the multicast group,
but Router2 doesn't list Host2 as a receiver, then use tcpdump on
both Host2 and Router2 to see whether they see the IGMP control
messages from each other.

Depends on the above results we can try to explore further where the
problem is.

Pavlin

P.S. This is not related to your problem, but don't forget that the
sender's TTL of the multicast packets should be large enough to
reach the receiver. Typically, the default TTL for multicast tools
is 1 so you may have to explicitly set it to some larger value.


> I wish to configure a simple pim-sm network to send my multicast
> messages to the remote site. I use the liveCD with xorp. My multicast
> messages do not arrive to the remote network. Will you please help me
> why, or what should be done on another way?
> 
> My test network:
> Host1-[net1]-Router1-[net0]-Router2-[net2]-Host2
> 
> where
> - Router1, Router2: xorp routers, see config below
> - Host1, Host2 are hosts on different sites that wish to exchange
> multicast datagrams of IP 239.253.0.200.
> - net0: 192.168.64.0/24
> - net1: 10.7.7.0/24
> - net2: 10.6.6.0/24
> 
> I have 'mtest' on both Hosts to register them to igmp multicast group
> of 239.253.0.200. Then from Host1 I send udp messages to this
> multicast address, which is expected to seen on Host2. I tried
> bootstrap and static rp setting as well on the routers, but this
> traffic does not arrive to Host2 or vice versa.
> 
> Tcpdump shows that routers see the 239.253.0.200 multicast traffic
> coming in the inside interface (net1|net2), but router does not put
> this multicast traffic to its outside inteface on net0.
> What am I doing wrong?
> 
> Router1 is the RP
> Router1: xorpsh -> configure -> show
> -------------------------------
>  interfaces {
>         interface lnc0 {
>             description: "lnc0"
>             disable: false
>             vif lnc0 {
>                 disable: false
>                 address 10.7.7.1 {
>                     prefix-length: 24
>                     broadcast: 10.7.7.255
>                     disable: false
>                 }
>             }
>             discard: false
>         }
>         interface lnc1 {
>             description: "lnc1"
>             disable: false
>             vif lnc1 {
>                 disable: false
>                 address 192.168.64.177 {
>                     prefix-length: 24
>                     broadcast: 192.168.64.255
>                     disable: false
>                 }
>             }
>             discard: false
>         }
>         targetname: "fea"
>     }
>     fea {
>         unicast-forwarding4 {
>             disable: false
>         }
>         targetname: "fea"
>     }
>     plumbing {
>         mfea4 {
>             disable: false
>             interface lnc0 {
>                 vif lnc0 {
>                     disable: false
>                 }
>             }
>             interface lnc1 {
>                 vif lnc1 {
>                     disable: false
>                 }
>             }
>             interface register_vif {
>                 vif register_vif {
>                     disable: false
>                 }
>             }
>             traceoptions {
>                 flag {
>                     all {
>                         disable: false
>                     }
>                 }
>             }
>             targetname: "MFEA_4"
>         }
>     }
>     protocols {
>         static {
>             route4 10.6.6.0/24 {
>                 next-hop: 192.168.64.160
>                 metric: 1
>             }
>             mrib-route4 10.6.6.0/24 {
>                 next-hop: 192.168.64.160
>                 metric: 1
>             }
>             targetname: "static_routes"
>             disable: true
>         }
>         igmp {
>             disable: false
>             interface lnc0 {
>                 vif lnc0 {
>                     disable: false
>                 }
>             }
>             interface lnc1 {
>                 vif lnc1 {
>                     disable: false
>                 }
>             }
>             traceoptions {
>                 flag {
>                     all {
>                         disable: false
>                     }
>                 }
>             }
>             targetname: "IGMP"
>         }
>         pimsm4 {
>             disable: false
>             interface lnc0 {
>                 vif lnc0 {
>                     disable: false
>                     dr-priority: 1
>                 }
>             }
>             interface lnc1 {
>                 vif lnc1 {
>                     disable: false
>                     dr-priority: 1
>                 }
>             }
>             interface register_vif {
>                 vif register_vif {
>                     disable: false
>                     dr-priority: 1
>                 }
>             }
>             static-rps {
>                 rp 192.168.64.177 {
>                     group-prefix 224.0.0.0/4 {
>                         rp-priority: 192
>                         hash-mask-len: 30
>                     }
>                     group-prefix 239.253.0.0/24 {
>                         rp-priority: 192
>                         hash-mask-len: 30
>                     }
>                 }
>             }
>             switch-to-spt-threshold {
>                 disable: false
>                 interval-sec: 100
>                 bytes: 102400
>             }
>             traceoptions {
>                 flag {
>                     all {
>                         disable: false
>                     }
>                 }
>             }
>             targetname: "PIMSM_4"
>         }
>         fib2mrib {
>             disable: false
>             targetname: "fib2mrib"
>         }
>     }
> ----------------------------------------
> 
> Router1:
> 
> Xorp> show pim interface
> Interface    State    Mode   V PIMstate Priority DRaddr          Neighbors
> lnc0         UP       Sparse 2 DR              1 10.7.7.1                0
> lnc1         UP       Sparse 2 DR              1 192.168.64.177          1
> register_vif UP       Sparse 2 DR              1 10.7.7.1                0
> 
> Xorp> show pim neighbors
> Interface    DRpriority NeighborAddr    V Mode   Holdtime Timeout
> lnc1                  1 192.168.64.160  2 Sparse      105      88
> 
> Xorp> show pim rps
> RP              Type      Pri Holdtime Timeout ActiveGroups GroupPrefix
> 192.168.64.177  static    192       -1      -1            0 224.0.0.0/4
> 192.168.64.177  static    192       -1      -1            1 239.253.0.0/24
> 
> Xorp> show pim mrib
> DestPrefix         NextHopRouter   VifName VifIndex MetricPref Metric
> 10.6.6.0/24        10.6.6.1        lnc0    0                 0      0
> 10.7.7.0/24        192.168.64.177  lnc1    1                 1      1
> 192.168.64.0/24    192.168.64.160  lnc1    1                 0      0
> 
> Xorp> show pim join
> Group           Source          RP              Flags
> 
> Xorp> show pim mfc
> Group           Source          RP
> 
> 
> ----------------------------------------
> 
> Router2:
> 
> Xorp> show pim interface
> Interface    State    Mode   V PIMstate Priority DRaddr          Neighbors
> lnc0         UP       Sparse 2 DR              1 10.6.6.1                0
> lnc1         UP       Sparse 2 NotDR           1 192.168.64.177          1
> register_vif UP       Sparse 2 DR              1 10.6.6.1                0
> 
> Xorp> show pim neighbors
> Interface    DRpriority NeighborAddr    V Mode   Holdtime Timeout
> lnc1                  1 192.168.64.177  2 Sparse      105      78
> 
> Xorp> show pim rps
> RP              Type      Pri Holdtime Timeout ActiveGroups GroupPrefix
> 192.168.64.177  static    192       -1      -1            0 224.0.0.0/4
> 192.168.64.177  static    192       -1      -1            0 239.253.0.0/24
> 
> Xorp> show pim mrib
> DestPrefix         NextHopRouter   VifName VifIndex MetricPref Metric
> 10.6.6.0/24        192.168.64.160  lnc1    1                 1      1
> 10.7.7.0/24        10.7.7.1        lnc0    0                 0      0
> 192.168.64.0/24    192.168.64.177  lnc1    1                 0      0
> 
> Xorp> show pim join
> Group           Source          RP              Flags
> 
> Xorp> show pim mfc
> Group           Source          RP
> 
> 
> 
> Thank you for any advice.
> Hajni
> 
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