Configuring Attr_Set Attribute Encapsulation or Parsing

On BGP MPLS/VPN networks, EBGP peer relationships are established between PEs and CEs in most cases. Attributes of the routes advertised by CEs are modified during transmission over the intermediate backbone network, or the attributes affect the backbone network. In this case, BGP has been extended to allow the intermediate backbone network to transparently transmit the routes advertised by CEs. After receiving a route from a CE, the local PE encapsulates the attributes of the route in the Attr_Set attribute and then sends the route to the remote PE. Upon receipt of the route, the remote PE parses the Attr_Set attribute. This process ensures that the route attributes are transparently transmitted over the backbone network.