3

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
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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

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

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