Scaling address resolution for massive data centers

A network device disposed at an interface between a first access segment and an interconnecting layer of a data center, comprising:

• an address resolution processor configured to:
• receive a local data packet from the first access segment, the local data packet including a specified layer 3 address;
• selectively broadcast an address resolution request in a broadcast domain of the data center, the address resolution request:
• requesting a layer 2 address corresponding to the specified layer 3 address;
• receive a response to the address resolution request;
• and
• update an address cache, based on the received response, to include an entry specifying the layer 2 address of an edge device of an access segment which has a virtual machine having a respective layer 3 address corresponding to the specified layer 3 address, the entry also specifying said respective layer 3 address.

An address resolution method, which when executed by a network device disposed at an interface between a first access segment and an interconnecting layer of a data center, comprises:

• receiving a local data packet from the first access segment, the local data packet including a specified layer 3 address;
• selectively broadcasting an address resolution request in a broadcast domain of the data center, the address resolution request:
• requesting a layer 2 address corresponding to the specified layer 3 address;
• receiving a response to the address resolution request;
• and
• updating an address cache, based on the received response, to include an entry specifying an access segment which has a virtual machine having a respective layer 3 address corresponding to the specified layer 3 address.

A network including a plurality of access segments joined by an interconnecting layer, and selected access segments of the plurality of access segments each comprises a network device, the network device comprising:

• an address resolution processor configured to:
• receive an address request addressed to machines in a broadcast domain of the network, the address request:
• specifying a layer 2 address,
• requesting a layer 2 address of some other virtual machine in the network, and
• specifying a layer 3 address;
• transmit a local message over an access segment requesting the respective layer 2 address of a virtual machine which has a respective layer 3 address corresponding to the specified layer 3 address;
• and
• in response to receiving a local reply to the local message, transmit a reply message to the specified layer 2 address, the reply message providing the layer 2 address of the network device and the specified layer 3 address.

A network including a plurality of access segments joined by an interconnecting layer, and selected access segments of the plurality of access segments each comprises a network device, the network device comprising:

• an address resolution processor configured to:
• receive a local data packet from a first access segment, the local data packet including a specified layer 3 address;
• selectively broadcast an address resolution request in a broadcast domain of the network, the address resolution request requesting a layer 2 address corresponding to the specified layer 3 address;
• receive a response to the address resolution request;
• and
• update an address cache, based on the received response, to include an entry specifying a second access segment which has a virtual machine having a respective layer 3 address corresponding to the specified layer 3 address.

A cache table reduction method for a network device, the method comprising:

• the network device configured to receive a first address request indicating one source layer 3 address and a specified layer 2 address;
• the network device further configured to receive a second address request indicating another source layer 3 address and the same specified layer 2 address;
• and
• an address resolution processor of the network device configured to store, in a cache, the one and the another source layer 3 address in association with only a single instance of the specified layer 2 address.