Patent ID: 9118604
Filing Date: 2015-08-25
Classification: H04L

Abstract:
1. A method for routing packets, the method comprising: receiving, at an interface of a first network device of a plurality of network devices in a leaf tier, a first packet, wherein the first packet comprises a first destination Internet Protocol (IP) address and wherein each of the plurality of network devices comprises a supernet table and a non-overlapping portion of a routing table; determining, using the first destination IP address and the supernet table, a first IP address of a second network device to which the packet is to be sent, wherein the second network device is one of the plurality of network devices in the leaf tier, wherein the supernet table comprises a plurality of entries, wherein each of the plurality of entries comprises a non-overlapping IP address range and specifies a corresponding one of the plurality of network devices in the leaf tier, and wherein the non-overlapping portion of the routing table on the second network device comprises a route for the first packet; determining, by the first network device, a first media access control (MAC) address of the second network device using the first IP address; rewriting, by the first network device, the first packet to obtain a first rewritten packet, wherein the first rewritten packet comprises the first MAC address as a destination MAC address of the first rewritten packet and the first destination IP address; sending the first rewritten packet to a third network device, wherein the third network device is not in the leaf tier; determining, by the third network device using the destination MAC address of the first rewritten packet, to forward the first rewritten packet from the third network device to the second network device; sending the first rewritten packet to the second network device; performing, by the second network device using the destination MAC address of the first rewritten packet, a first MAC pointer table lookup to determine that a first routing table lookup is to be performed using the first destination IP address of the first rewritten packet; performing, by the second network device, the first routing table lookup, wherein the first routing table lookup comprises using the non-overlapping portion of the routing table on the second network device to determine a second IP address corresponding to a first external network device to which the packet is to be sent; determining, by the second network device, a second MAC address of the first external network device using the second IP address; rewriting the first rewritten packet to obtain a second rewritten packet, by the second network device using the second MAC address, wherein the second rewritten packet comprises the second MAC address as a destination MAC address of the second rewritten packet and the first destination IP address; sending the second rewritten packet from a first interface on the second network device to the first external network device, wherein the first interface is associated with the second MAC address.