Multicast IGMP Proxy

[ReneMolenaar]

@carloemmanuelvalle @Amjad.Abdullah

@carloemmanuelvalle

I don’t know if I’m wrong but I saw membership report on R1 received by G0/2, it’s suppose that that interface is an UDL and you can’t receive traffic from it. G0/2 just can send traffic but not receive is true?

@Amjad.Abdullah

Moreover, I can see that the satellite link is used both ways in both directions! How is it a UDL then?! That is really confusing to me.

Let me try to explain this a bit more. The debug output is very confusing…it shows the GigabitEthernet0/2 interface on R1 (satellite link) while in reality, R1 doesn’t receive the packet on this interface.

I started this topology and did another wireshark capture. Here are the MAC addresses of the GigabitEthernet0/2 and 0/3 interfaces of R1 and R2:

Interface	Address
R1 Gi0/2	fa16.3e9d.174c
R1 Gi0/3	fa16.3ee5.573a
R2 Gi0/2	fa16.3ed6.6294
R2 Gi0/3	fa16.3e26.cf96

Now look at the wireshark captures below:

The output above is a capture on R1’s Gi0/3 interface. You can see the source MAC address is R2’s Gi0/3 interface. The destination is R1’s Gi0/3 interface.

Here’s a capture of R1’s Gi0/2 interface:

The output above shows the source is R1’s Gi0/2 interface. The debug output is confusing as it never shows the Gi0/3 interface while in reality, that’s where we receive the membership report on.

@Amjad.Abdullah

I would say that there must be an explanation about how do we choose which is the main link and which is the back link (I didn’t know how to choose that after reading the lesson). I think it worth shedding some light on this part and how the main or back link are chosen (either manually or dynamically) because I couldn’t see any real piece of config on the internet link interfaces between R1 and R2. Moreover

I’ll edit the lesson to explain what each interface is used for. The Gi0/3 interfaces are “regular” internet connections and the Gi0/2 interfaces is a unidirectional satellite connection.

Hope this helps! If not let me know

Rene