16.2.1. Inclusive Trees

16.2.1. Inclusive Trees

An Inclusive tree allows the use of a single multicast distribution tree, referred to as an Inclusive P-multicast tree, in the SP network to carry all the multicast traffic from a specified set of EVPN instances on a given PE. A particular P-multicast tree can be set up to carry the traffic originated by sites belonging to a single EVPN instance, or to carry the traffic originated by sites belonging to several EVPN instances. The ability to carry the traffic of more than one EVPN instance on the same tree is termed 'Aggregation', and the tree is called an Aggregate Inclusive P-multicast tree or Aggregate Inclusive tree for short. The Aggregate Inclusive tree needs to include every PE that is a member of any of the EVPN instances that are using the tree. This implies that a PE may receive BUM traffic even if it doesn't have any receivers that are interested in receiving that traffic.

An Inclusive or Aggregate Inclusive tree as defined in this document is a P2MP tree. A P2MP tree is used to carry traffic only for EVPN CEs that are connected to the PE that is the root of the tree.

The procedures for signaling an Inclusive tree are the same as those in [RFC7117], with the VPLS A-D route replaced with the Inclusive Multicast Ethernet Tag route. The P-tunnel attribute [RFC7117] for an Inclusive tree is advertised with the Inclusive Multicast Ethernet Tag route as described in Section 11 ("Handling of Multi-destination Traffic"). Note that for an Aggregate Inclusive tree, a PE can "aggregate" multiple EVPN instances on the same P2MP LSP using upstream labels. The procedures for aggregation are the same as those described in [RFC7117], with VPLS A-D routes replaced by EVPN Inclusive Multicast Ethernet Tag routes.