Method and System for L3 Bridging Using L3-To-L2 Mapping Database

1 . A method comprising:

creating an L3-L2 database on a first switch, the database having one or more entries, each entry: (a) associating a Level 3 (L3) unique identifier associated with a virtual local area network (VLAN) communicatively coupled to the first switch to a Level 2 (L2) unique identifier associated with the VLAN, and (b) associating the L3 unique identifier with a port of the first switch;

receiving a network packet at the first switch;

determining if a destination VLAN for the network packet has a corresponding entry in the L3-L2 database; and

switching the network packet to the port in response to a determination that the destination VLAN for the network packet has a corresponding entry in the L3-L2 database, such that the packet is communicated to one of: (a) the destination VLAN, and (b) a second switch intermediate to the first switch and the destination VLAN.

2 . A method according to claim 1 , further comprising switching the network packet in response to a determination that the destination VLAN for the network packet does not have a corresponding entry in the L3-L2 database, such that the packet is communicated to one of: (a) a router communicatively coupled to the first switch, and (b) a third switch intermediate to the first switch and the router.

3 . A method according to claim 2 , wherein the second switch and the third switch are the same switch.

4 . A method according to claim 1 , further comprising:

snooping address resolution protocol (ARP) packets received at the first switch; and

creating the L3-L2 database based on contents of the ARP packets.

5 . A method according to claim 1 , wherein the L3 unique identifier is an Internet Protocol (IP) address.

6 . A method according to claim 1 , wherein the L2 unique identifier is a Service VLAN address.

7 . A method according to claim 1 , wherein the L2 unique identifier is a Media Access Control (MAC) address.

8 . A switch comprising:

logic for creating an L3-L2 database on the switch, the database having one or more entries, each entry: (a) associating a Level 3 (L3) unique identifier associated with a virtual local area network (VLAN) communicatively coupled to the switch to a Level 2 (L2) unique identifier associated with the VLAN, and (b) associating the L3 unique identifier with a port of the switch;

logic for receiving a network packet at the switch;

logic for determining if a destination VLAN for the network packet has a corresponding entry in the L3-L2 database; and

logic for switching the network packet to the port in response to a determination that the destination VLAN for the network packet has a corresponding entry in the L3-L2 database, such that the packet is communicated to one of: (a) the destination VLAN, and (b) a second switch intermediate to the switch and the destination VLAN.

9 . A switch according to claim 8 , further comprising logic for switching the network packet in response to a determination that the destination VLAN for the network packet does not have a corresponding entry in the L3-L2 database, such that the packet is communicated to one of: (a) a router communicatively coupled to the switch and (b) a third switch intermediate to the switch and the router.

10 . A switch according to claim 9 , wherein the second switch and the third switch are the same switch.

11 . A switch according to claim 8 , further comprising:

logic for snooping address resolution protocol (ARP) packets received at the first switch; and

logic for creating the L3-L2 database based on contents of the ARP packets.

12 . A switch according to claim 8 , wherein the L3 unique identifier is an Internet Protocol (IP) address.

13 . A switch according to claim 8 , wherein the L2 unique identifier is a Service VLAN address.

14 . A switch according to claim 8 , wherein the L2 unique identifier is a Media Access Control (MAC) address.

15 . An apparatus comprising:

means for creating an L3-L2 database on a first switch, the database having one or more entries, each entry: (a) associating a Level 3 (L3) unique identifier associated with a virtual local area network (VLAN) communicatively coupled to the first switch to a Level 2 (L2) unique identifier associated with the VLAN, and (b) associating the L3 unique identifier with a port of the first switch;

means for receiving a network packet at the first switch;

means for determining if a destination VLAN for the network packet has a corresponding entry in the L3-L2 database; and

means for switching the network packet to the port in response to a determination that the destination VLAN for the network packet has a corresponding entry in the L3-L2 database, such that the packet is communicated to one of: (a) the destination VLAN, and (b) a second switch intermediate to the first switch and the destination VLAN.

16 . An apparatus according to claim 15 , further comprising means for switching the network packet in response to a determination that the destination VLAN for the network packet does not have a corresponding entry in the L3-L2 database, such that the packet is communicated to one of: (a) a router communicatively coupled to the first switch and (b) a third switch intermediate to the first switch and the router.

17 . An apparatus according to claim 16 , wherein the second switch and the third switch are the same switch.

18 . An apparatus according to claim 15 , further comprising:

means for snooping address resolution protocol (ARP) packets received at the first switch; and

means for creating the L3-L2 database based on contents of the ARP packets.

19 . An apparatus according to claim 15 , wherein the L3 unique identifier is an Internet Protocol (IP) address.

20 . An apparatus according to claim 15 , wherein the L2 unique identifier is a one of a Service VLAN address and a Media Access Control (MAC) address.