A switch configured to be a member of a first fabric switch , the switch comprising: a link aggregation module operable to mark an ingress-switch field of a frame with a virtual switch identifier, wherein the virtual switch identifier is associated with the switch and a second switch , and wherein the second switch is a member of a second fabric switch ; wherein the virtual switch identifier is selected from a range of identifiers associated with both the first fabric switch and the second fabric switch ; and wherein each of the first fabric switch and the second fabric switch is operable to accommodate a plurality of switches and operate as a single switch; wherein the switch is a routing bridge (RBridge) operable in accordance with Transparent Interconnection of Lots of Links (TRILL) protocol; the switch further comprising: a TRILL-supported edge port, operable to be coupled to a TRILL primary link , wherein the edge port is operable as an output port for frames destined outside of the first fabric switch ; wherein the TRILL primary link is a link between the switch in the first fabric switch and the second switch in the second fabric switch ; a TRILL primary module operable to: preclude the switch from removing TRILL encapsulation from a TRILL-encapsulated frame in response to determining the TRILL-encapsulated frame to be a broadcast, unknown unicast, or multicast frame; and determine the TRILL-supported edge port as the output port for the TRILL-encapsulated frame; and the switch configured to forward the determined broadcast, unknown unicast, or multicast TRILL-encapsulated frame via the TRILL-supported edge port coupled to the TRILL primary link. a link aggregation module operable to mark an ingress-switch field of a frame with a virtual switch identifier, wherein the virtual switch identifier is associated with the switch and a second switch , and wherein the second switch is a member of a second fabric switch ; wherein the virtual switch identifier is selected from a range of identifiers associated with both the first fabric switch and the second fabric switch ; and wherein each of the first fabric switch and the second fabric switch is operable to accommodate a plurality of switches and operate as a single switch; wherein the switch is a routing bridge (RBridge) operable in accordance with Transparent Interconnection of Lots of Links (TRILL) protocol; the switch further comprising: a TRILL-supported edge port, operable to be coupled to a TRILL primary link , wherein the edge port is operable as an output port for frames destined outside of the first fabric switch ; wherein the TRILL primary link is a link between the switch in the first fabric switch and the second switch in the second fabric switch ; a TRILL primary module operable to: preclude the switch from removing TRILL encapsulation from a TRILL-encapsulated frame in response to determining the TRILL-encapsulated frame to be a broadcast, unknown unicast, or multicast frame; and determine the TRILL-supported edge port as the output port for the TRILL-encapsulated frame; preclude the switch from removing TRILL encapsulation from a TRILL-encapsulated frame in response to determining the TRILL-encapsulated frame to be a broadcast, unknown unicast, or multicast frame; and determine the TRILL-supported edge port as the output port for the TRILL-encapsulated frame; and the switch configured to forward the determined broadcast, unknown unicast, or multicast TRILL-encapsulated frame via the TRILL-supported edge port coupled to the TRILL primary link. <EOS>