VMware, Inc.
Pre-allocating port groups for a very large scale NAT engine

Abstract:

Some embodiments provide a novel method for performing network address translation to share a limited number of external source network addresses among a large number of connections. Instead of allocating an external source network address for an egressing packet just based on its internal source network address, the method of some embodiments allocates the external source network address based on the egressing packet's source network address and destination network address. This allows a limited number of external source network addresses to be re-used for different destination network address. For instance, in some embodiments, the method's network address allocation scheme allows the same 64K (e.g., 2{circumflex over ( )}16) external source ports to be used for 64K connections for each destination network address.