[Xorp-users] Multicast traffic is not forwarded in a specific deployment as mentioned in the mail

Igor Maravić igorm at etf.rs
Thu Jul 5 00:19:48 PDT 2012


I'm 99% sure that this isn't Xorp problem :)
Linux, won't forward packets if the src address in packet is unknown to him.
So, at least I think that, you have 2 possible solutions:
1. Turn off rp filtering on Xorp box (reference -
http://lartc.org/howto/lartc.kernel.html)
2. Set static interface route to 192.168.17.17/32 on eth3, with Xorp
(
    interface-route 192.168.17.17/32 {
        next-hop-interface: "eth3"
        next-hop-vif: "eth3"
    }
)

Let me know if it worked. :)
BR
Igor

2012/7/5 Ganesh Reddy K <ganeshreddyk at gmail.com>:
> Hi ,
>
> We are trying to exercise a multicast traffic forwarding scenario  on
> a powerPC device:--
>
> After H2 subscribed for the Group G1, The  G1 multicast traffic is not
> receiving at H2.  But, when the H1 ip is in the same subnet,  traffic
> is properly forwarded to H2 without any issues.
>
> Test setup:--
>
> H1   ------------------------------------ eth3   XORP  eth2
> -------------------------------------------- H2
>
> 192.168.17.17            192.168.4.2             192.168.3.2
>                   192.168.3.10
>
> UDP-G1 multicaststream
>                               Mcast listener for G1
>
> G1-239.7.7.7
>
>
> 1) COnfigured XORP on the device, xorp.conf contents are .
>
> ===========XORP configuration  ===========
>
> protocols {
>         fib2mrib {
>         }
>         igmp {
>
>                 interface eth0 {
>                         vif eth0 {
>                                 version: 3
>                                 }
>                         }
>                 interface eth1 {
>                         vif eth1 {
>                                 version: 3
>                                 }
> }
>             interface eth2 {
>                 vif eth2 {
>                    version: 3
>                 }
> }
> interface eth3 {
>
>                vif eth3 {
>                     version: 3
> }
>             }       }
>
>
>         pimsm4 {
>             interface eth0 {
>
>           vif eth0 {
>                 }
>             }
>             interface "register_vif" {
>                 vif "register_vif" {
>                 }
>
>          }
>            interface eth1 {
>                 vif eth1 {
>
>         }
>             }
>             interface eth2 {
>                 vif eth2 {
>                 }
>             }
>             interface eth3 {
>
>         vif eth3 {
>                 }
>             }
>         }
>     }
>     fea {
>         unicast-forwarding4 {
>         }
>
>
> unicast-forwarding6 {
>         }
>     }
>     interfaces {
>         interface eth0 {
>             vif eth0 {
>            }
>
> default-system-config {
>             }
>         }
>         interface eth1 {
>
>          vif eth1 {
>             }
>             default-system-config {
>        }
>         }
>         interface eth2 {
>             vif eth2 {
>
>    }
>             default-system-config {
>             }
>       }
>
> interface eth3 {
>             vif eth3 {
>             }
>
> default-system-config {
>             }
>         }
>     }
>    plumbing {
>
> mfea4 {
>             interface eth0 {
>                 vif eth0 {
>
>      }
>             }
>             interface "register_vif" {
>
>  vif "register_vif" {
>                 }
>             }
>
> interface eth1 {
>                 vif eth1 {
> }
>
> }
>
>             interface eth2 {
>                 vif eth2 {
> }
>
>        }
>             interface eth3 {
>                 vif eth3 {
>
>       }
>             }
>         }
>    }
>
> ============= xorp configuration =============
>
> 2) From  H1, started sending UDP stream targeting G1 using VLC player.
>
> Capture of  "tcpdump  -ni eth3" on Device shows the UDP-G1 packets  as below
> ..
> 09:27:50.081561 IP 192.168.17.17.4146 > 239.7.7.7.1234: UDP, length 1328
> ..
>
> 3) added a static route for the unknown network on Device (i.e route
> add -net 192.168.17.17/32 dev eth3)
>
> 4) From H2, started VLC listener for the group G1.
>
> It is verified in the Device that, IGMP join is received.
> capture of " show igmp group" on XORP console
>
> Interface    Group           Source          LastReported Timeout V State
>
> eth0         224.0.0.2       0.0.0.0         192.168.1.2      223 3     E
>
> eth0         224.0.0.13      0.0.0.0         192.168.1.2      223 3     E
>
> eth0         224.0.0.22      0.0.0.0         192.168.1.2      223 3     E
>
> eth1         224.0.0.2       0.0.0.0         192.168.2.2      225 3     E
>
> eth1         224.0.0.13      0.0.0.0         192.168.2.2      225 3     E
>
> eth1         224.0.0.22      0.0.0.0         192.168.2.2      225 3     E
>
> eth2         224.0.0.2       0.0.0.0         192.168.3.2      231 3     E
>
> eth2         224.0.0.13      0.0.0.0         192.168.3.2      231 3     E
>
> eth2         224.0.0.22      0.0.0.0         192.168.3.2      231 3     E
>
> eth2         239.1.1.1       0.0.0.0         192.168.3.10     228 3     E
>
> eth2         239.7.7.7       0.0.0.0         192.168.3.10     228 3     E
>
> eth2         239.255.255.250 0.0.0.0         192.168.3.10     228 3     E
>
> eth3         224.0.0.2       0.0.0.0         192.168.4.2      230 3     E
>
> eth3         224.0.0.13      0.0.0.0         192.168.4.2      230 3     E
>
> eth3         224.0.0.22      0.0.0.0         192.168.4.2      230 3     E
>
> root at p4080ds>
>
> 5) But the traffic is not receiving at H2. Below is the statistics
> related ip_mr   on the device
>
> cat /proc/net/ip_mr*
>
> Group    Origin   Iif     Pkts    Bytes    Wrong Oifs
> EF070707 C0A81111 3        453   614268        0
> Interface      BytesIn  PktsIn  BytesOut PktsOut Flags Local    Remote
>  0 eth0              0       0         0       0 00000 C0A80102 00000000
>  1 eth1              0       0         0       0 00000 C0A80202 00000000
>  2 eth2              0       0         0       0 00000 C0A80302 00000000
>  3 eth3        3971724    2929         0       0 00000 C0A80402 00000000
>  4 pimreg            0       0         0       0 00004 C0A80102
>
>
> 6) But, when the H1 ip is in the same subnet,  traffic is properly
> forwarded to H2 without any issues.
>
> Did anybody tried this scenario ?
>
> Thanks,
> Ganesh
>
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> Xorp-users at xorp.org
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