You can enable flow on the physical bearer and it will automatically add the flow configuration to any subsequent sub-interfaces using ip route-cache flow.

Is there any way to disable/enable CDP on the physical interface and it automatically cascades to the sub-interfaces?

I need to enable CDP on 350 devices for the LAN facing ports only via a script, the WAN interface is always g0/0 but sites have a variety of VRFs/sub-interfaces.

  • I assume disabling cdp globally is not desired, correct? – Mike Pennington May 13 '14 at 12:55
  • nope , customer has paid to have it enabled on all LAN ports , as we run juniper PE's I want it disabled on WAN interfaces as our monitoring platform complains about the unknown protocol drops – DrBru May 13 '14 at 13:06
  • Are you open to a config generation script? – Mike Pennington May 13 '14 at 13:08
  • @Mike Pennington can you elaborate on the config generation script ? .. although by you referring to a script , can I assume no "single" command is available like the flow command ? – DrBru May 13 '14 at 13:22
  • Actually, I am not sure cdp is supported on subinterfaces; see this supportforums thread. If it is supported by your use case, a simple perl or python script could build the cdp disable config. For more elaborate needs, consider ciscoconfparse – Mike Pennington May 13 '14 at 13:45

CDP is not sent per subinterface. CDP is sent to a specific, link-only, multicast address that is sent either on the physical interface, or only one subinterface. Cisco has a document, Behavior of Cisco Discovery Protocol between Routers and Switches, that describes the behavior

enter image description here

You can disable CDP on the physical and subinterfaces by disabling is on the physical interface.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.