Cef adjacency

can you explain the different types of cef adjacency states - punt , glean, discard, null, drop with examples and configuration?

may be a topology example

  • Null adjacency: used to send packets to the null0 interface.
  • Drop adjacency: you’ll see this for packets that can’t be forwarded because of encapsulation errors, routes that cannot be resolved or protocols that are not supported.
  • Discard adjacency: this is for packets that have to be discarded because of an access-list or other policy.
  • Punt adjacency: used for packets that can't be forwarded by CEF. They will be "punted" to the next switching method (fast switching and process switching).
  • Glean adjacency: used for directly connected routes. It's used to tell the router that it should check the ARP table since it can reach the device directly.
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Thanks for the adjacency explanation :slight_smile: