Support of a large number of VLANs in a bridged network

摘要

Disclosed are, inter alia, methods, apparatus, data structures, computer-readable media, mechanisms, and means for supporting a large number of virtual local area networks (VLANS) in a bridged network. Packets are received that include 802.1Q Virtual Local Area Network (VLAN) identifiers (VIDs). However, rather than accessing the VLAN forwarding information directly based on the VID as conventionally performed, the VLAN forwarding information to use for a particular packet is determined based on an interface (e.g., virtual or physical interface, port, MPLS label, GRE tunnel or other abstraction of the interface). In other words, the interface associated with the packet identifies a context for determining the VLAN forwarding information based on the VID included in the packet. Therefore, network bridging devices can support more VLANs than that imposed by the 4096 possible values of a VID.

主权项

1. A method, comprising:
a plurality of operations performed by a network bridge supporting more than 4096 independent Virtual Local Area Networks (VLANs), wherein a VLAN identifier included in a received frame is a twelve-bit 802.1Q compliant VLAN identifier, wherein the plurality of operations include: receiving a particular frame on a particular interface of a plurality of interfaces of the network bridge, said received particular frame including a particular 802.1Q compliant VLAN identifier wherein the particular interface is identified based on a particular tunnel on which the particular frame was received; determining a particular VLAN corresponding to said received particular frame based on the particular 802.1Q compliant VLAN identifier and the particular interface, wherein the network bridge is currently supporting a second VLAN independent of the particular VLAN with the second VLAN also being associated with the particular 802.1Q compliant VLAN identifier; forwarding said received particular frame out one or more particular interfaces of the network bridge, said one or more particular interfaces corresponding to the particular VLAN; with a VLAN identifier of said forwarded particular frame being the particular 802.1Q compliant VLAN identifier; receiving a second frame on a second interface of the plurality of interfaces of the network bridge, the second frame including the particular 802.1Q compliant VLAN identifier; identifying the second VLAN corresponding to the second frame based on the particular 802.1Q compliant VLAN identifier and the second interface; forwarding the second frame out one or more interfaces of the network bridge, said one or more interfaces corresponding to the second VLAN; wherein: the particular 802.1Q compliant VLAN identifier, of the particular frame, is mapped into a particular internal number representing the particular VLAN based on the particular 802.1Q compliant VLAN identifier and the particular interface; the particular 802.1Q compliant VLAN identifier, of the second frame, is mapped into a second internal number representing the second VLAN based on the particular 802.1Q compliant VLAN identifier and the second interface; identifying based on the particular internal number where to forward the particular frame; and identifying based on the second internal number where to forward the second frame.