The SSR has a bond interface with multiple VLANs and is configured as a DHCP server for those VLANs. APs connected to these VLANs were sending DHCP requests, but were not receiving IP addresses from the SSR.

• APs were generating and forwarding DHCP requests, but the requests were not received by the SSR.
• BGP routes were not being advertised to the neighbors.
• Network interfaces configured on bond0 were operationally down.

Root Cause

The bond0 device interface was operationally down because the LACP state was stuck in Detached instead of Collecting, Distributing.

The switch interfaces connected to the SSR bond members had an issue with the LACP service, which was not running. Restarting the LACP service and rebooting the switch did not resolve the issue.

Resolution

1. Verified the status of the interfaces using:
   • show network-interface
   • show device-interface
2. Confirmed that bond0 was operationally down and its LACP state was Detached.
3. On the connected switch, reconfigured the port profile and re-selected the interfaces participating in the LACP bundle.
4. After the port profile was reconfigured:
   • The LACP service started successfully.
   • The LACP state changed to Collecting, Distributing.
   • bond0 changed to Operationally UP.
   • Network interfaces configured on bond0 also changed to UP.

Result

Once bond0 became operationally UP:

• The APs successfully received IP addresses from the SSR DHCP server.
• The corresponding routes were successfully advertised to the BGP neighbors.

Key Takeaway

When DHCP requests are not reaching an SSR DHCP server and the affected VLAN interfaces are configured over a bond interface, verify the operational status of the bond and its LACP state. An LACP state of Detached can prevent the underlying interfaces from becoming operationally UP, resulting in both DHCP and routing failures.