Multicast from Gi to Fa port on Cisco IR1101-K9 router


We are struggling a bit with what may be a simple problem.
We have been at it some time without luck (I am new and got assigned this task), so maybe you can take a crack at it? :slight_smile:

We have a Cisco IR1101-K9 industrial router for a “proof of concept” to present future customers.
It has one Gi port and four Fa ports.

A workstation is broadcasting data:
Multicast IP:
Goes into the GigabitEthernet0/0/0 port (IP

Then we have a PC to receive the data (IP (not important)).
Connected to VLAN 1 (on the FastEthernet0/0/1 port) with VLAN 1 IP

By default no data is routed from Gi port to VLAN 1.

If possible, how do we pass multicast data from Gi port to VLAN 1?

(Multicast data works fine with both cables in VLAN 1)

Thank you…

Hello Dennis

So just to clarify, you have the following addressing:

  1. Workstation (mcast source) connected to Gi0/0/0
  2. Interface Gi0/0/0 with IP address
  3. VLAN 1 with IP address, and Fe0/0/1 is L2 port on VLAN 1
  4. PC with IP address connected to Fe0/0/1

I don’t have any subnetting information, but from what I see, there may be an issue with IP addressing. If Gi0/0/0 is an L3 port with an assigned IP address as I understand from your description, then traffic should be routed between the Workstation and the PC. But it looks like you’re using the same subnet (assuming /24 is being used everywhere).

As I understand it, you are probably not able to ping the PC directly from the Workstation. Before you tackle the multicast problem, make sure that network connectivity is indeed established.

Make sure that:

  1. The workstation IP address, subnet mask, and default gateway are correct.
  2. The IP address of the Gi 0/0/0 interface is correct. This will play the role of the workstation’s default gateway.
  3. The PC IP address, subnet mask and default gateway are correct
  4. The IP address of VLAN1 SVI is correct. This will play the role of the PC’s default gateway.

Take a look at these and once unicast communication between the Workstation and the PC is established, you can then go on to the multicast issue. Let us know how you get along!

I hope this has been helpful!


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