---
name: Adjacency
maintainer: Neale Ranns <nranns@cisco.com>
features:
  - An adjacency represents how to send different traffic types to a peer
  - The principles properties of an adjacency are the interface and rewrite.
    The rewrite will be prepended to the packet as it is forward through the
    interface.
  - The rewrite is provided either by the interface type. It can be constructed
    either from fixed interface properties (i.e. src,dst IP address on a P2P
    tunnel) or from a resolution protocol (like ARP on an Ethernet link).
  - An Adjacency is said to be complete when the rewrite is present and
    incomplete when it is not,
  - An adjacency that is a leaf in the DPO graph is terminal/normal (i.e on
    a physical interface). When not terminal it is termed a midchain (i.e.
    one on a virtual interface, e.g. GRE tunnel). Midchain adjacencies can be
    stacked/joined onto the the DPO graph that described subsequent forwarding
    (i.e. how to send the the GRE tunnel's destination address).
  - Glean adjacencies describe how to broadcast packets onto a subnet

description: "Adjacencies represent the next-hop information required to reach a directly connected neighbour."
state: production
properties: [API, CLI, MULTITHREAD]