TRILL (Transparent Interconnection of Lots of Links) uses distribution trees to deliver multi-destination frames. Multiple trees can be used by an ingress Routing Bridge (RBridge) for flows@ regardless of the VLAN@ Fine-Grained Label (FGL)@ and/or multicast group of the flow. Different ingress RBridges may choose different distribution trees for TRILL Data packets in the same VLAN@ FGL@ and/or multicast group. To avoid unnecessary link utilization@ distribution trees should be pruned based on one or more of the following: VLAN@ FGL@ or multicast destination address. If any VLAN@ FGL@ or multicast group can be sent on any tree@ for typical fastpath hardware@ the amount of pruning information is multiplied by the number of trees@ but there is limited hardware capacity for such pruning information. This document specifies an optional facility to restrict the TRILL Data packets sent on particular distribution trees by VLAN@ FGL@ and/or multicast groups@ thus reducing the total amount of pruning information so that it can more easily be accommodated by fast-path hardware.
RFC 7968-2016 history
2016RFC 7968-2016 Transparent Interconnection of Lots of Links (TRILL): Using Data Labels for Tree Selection for Multi-Destination Data