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

Ganesh Reddy K ganeshreddyk at gmail.com
Wed Jul 4 23:15:20 PDT 2012


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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