Layer 2 address translation for service provider wholesale IP sessions

An apparatus comprising:

• a first network interface, having a layer 2 network address, for connecting to a first layer 2 network;
• a second network interface for connecting to a second layer 2 network;
• and
• logic configured to:
• receive a first layer 2 network packet over the first network interface, the first layer 2 network packet having a layer 2 destination address and a layer 2 source address, the layer 2 destination address of the first layer 2 network packet being the layer 2 network address of the first network interface, the first layer 2 network packet encapsulating a layer 3 network packet, the layer 3 network packet having a layer 3 destination address, the layer 3 destination address being a layer 3 network address of a host;
• forward the first layer 2 network packet to a next-hop layer 3 device having a layer 2 network address by (a) associating the host with a particular next-hop layer 3 device connected to the second layer 2 network, (b) creating a modified first layer 2 network packet by overwriting the layer 2 destination address of the first layer 2 network packet with the layer 2 network address of the next-hop layer 3 device, and (c) sending the modified first layer 2 network packet over the second layer 2 network, the modified first layer 2 network packet retaining the original layer 2 source address of the first layer 2 network packet;
• receive a second layer 2 network packet over the second network interface, the second layer 2 network packet having a layer 2 destination address and a layer 2 source address, the layer 2 destination address of the second layer 2 network packet being the layer 2 network address of a client;
• and
• forward the second layer 2 network packet to the client by (a) creating a modified second layer 2 network packet by overwriting the layer 2 source address of the second layer 2 network packet with the layer 2 network address of the first network interface and (b) sending the modified second layer 2 network packet over the first layer 2 network, the modified second layer 2 network packet retaining the original layer 2 destination address.

A system comprising:

• a plurality of clients connected to a first layer 2 network;
• a plurality of servers connected to a second layer 2 network, each server having a layer 2 network address;
• and
• a network device connected to both the first and the second layer 2 networks, the network device having a layer 2 network address, the network device configured to:
• receive a first layer 2 network packet from a client of the plurality of clients over the first layer 2 network, the first layer 2 network packet having a layer 2 destination address and a layer 2 source address, the layer 2 destination address of the first layer 2 network packet being the layer 2 network address of the first network interface, the first layer 2 network packet encapsulating a layer 3 network packet, the layer 3 network packet having a layer 3 destination address, the layer 3 destination address being a layer 3 network address of a host;
• forward the first layer 2 network packet to a server of the plurality of servers, by (a) associating the host with a particular server, (b) creating a modified first layer 2 network packet by overwriting the layer 2 destination address of the first layer 2 network packet with the layer 2 network address of the server, and (c) sending the modified first layer 2 network packet over the second layer 2 network, the modified first layer 2 network packet retaining the original layer 2 source address of the first layer 2 network packet;
• receive a second layer 2 network packet over the second layer 2 network, the second layer 2 network packet having a layer 2 destination address and a layer 2 source address, the layer 2 destination address of the second layer 2 network packet being the layer 2 network address of a client of the plurality of clients;
• and
• forward the second layer 2 network packet to the client by (a) creating a modified second layer 2 network packet by overwriting the layer 2 source address of the second layer 2 network packet with the layer 2 network address of the first network interface and (b) sending the modified second layer 2 network packet over the first layer 2 network, the modified second layer 2 network packet retaining the original layer 2 destination address.

An apparatus comprising:

• a first network interface, having a layer 2 network address, for connecting to a first layer 2 network;
• a second network interface for connecting to a second layer 2 network;
• means for receiving a first layer 2 network packet over the first network interface, the first layer 2 network packet having a layer 2 destination address and a layer 2 source address, the layer 2 destination address of the first layer 2 network packet being the layer 2 network address of the first network interface, the first layer 2 network packet encapsulating a layer 3 network packet, the layer 3 network packet having a layer 3 destination address, the layer 3 destination address being a layer 3 network address of a host;
• means for forwarding the first layer 2 network packet to a next-hop layer 3 device having a layer 2 network address by (a) associating the host with a particular next-hop layer 3 device connected to the second layer 2 network, (b) creating a modified first layer 2 network packet by overwriting the layer 2 destination address of the first layer 2 network packet with the layer 2 network address of the next-hop layer 3 device, and (c) sending the modified first layer 2 network packet over the second layer 2 network, the modified first layer 2 network packet retaining the original layer 2 source address of the first layer 2 network packet;
• means for receiving a second layer 2 network packet over the second network interface, the second layer 2 network packet having a layer 2 destination address and a layer 2 source address, the layer 2 destination address of the second layer 2 network packet being the layer 2 network address of a client;
• and
• means for forwarding the second layer 2 network packet to the client by (a) creating a modified second layer 2 network packet by overwriting the layer 2 source address of the second layer 2 network packet with the layer 2 network address of the first network interface and (b) sending the modified second layer 2 network packet over the first layer 2 network, the modified second layer 2 network packet retaining the original layer 2 destination address.