L2Bridge not forwarding packets in SALT

[Alexander Wolosewicz]

Slice ID: 5182e632-92d5-4a3f-8fd5-c7b4882d8ba7

Some L2Bridge network services in the topology are not passing packets as they should. The same configuration on other sites is working fine, but not on SALT. The clearest example is communication between nodes r3 (52849f79-1df2-43c3-896f-38f0fc135356) and r4 (52849f79-1df2-43c3-896f-38f0fc135356). R3’s uses interface r3-r3p1-p1 with MAC 0E:B5:27:2C:30:B5 and R4 uses interface r4-r4p1-p1 with MAC of 12:75:85:B6:38:A9. Both are SharedNIC components. Attempting to send crafted ICMP packets from r3 to r4 (and r4 to r3), from each interface to each interface, with both the target or a broadcast destination MAC results in 0 received traffic across the link. There was no error during slice setup.

[Komal Thareja]

Thank you Alex for sharing this observation! I temporarily assigned IP addresses to these interfaces on r3 and 4 nodes and do not see ping working between them.

Network service as provisioned looks ok. I am reaching out to the network team and will keep you posted.

Thanks,

Komal

[Komal Thareja]

Hi Alex,

The network team reviewed the configuration and found no issues on the switch side. However, they observed that the MAC addresses for these interfaces have not been learned by the switch.

As a next step, they recommend removing the L2Bridge service and connecting both interfaces directly to FabNetV4 to verify if the network connectivity is restored.

Please perform this change using slice modify, so the same VMs and interfaces can be reused for validation. This helps us rule out the possibility that recreating the VMs might inadvertently resolve the issue.

Refer to this notebook for guidance on how to modify the slice.

Thanks,

Komal

[Alexander Wolosewicz]

Hi Komal,

Apologies for the long delay. I believe I’ve modified the slice so that they are both on a FabNetV4 connection, but they do not receive any ARP replies from the gateway so the pings still fail.

[Komal Thareja]

Thank you Alexander for sharing this. I have shared the details with the network team. Will keep you posted.

Thanks,

Komal

[Komal Thareja]

Hi Alexander,

Based on our investigation so far, the VMs from your slice that are not passing traffic were hosted on salt-w3.fabric-testbed.net. We’ve identified that none of the VMs on this host are able to pass traffic. As a result, we have placed this worker into Maintenance mode and are actively investigating the issue.

You should be able to create a new slice without encountering this problem, as salt-w3 is now in Maintenance and will not be used for any new slices on the SALT site.

Thanks,

Komal

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