US Patent 11108686 Port allocation at distributed network address translators

A node of a network address translator obtains a first packet. A particular port number to be used as a substitute port for a packet flow associated with the first packet is determined using at least a first intermediate hash result, a particular flow hash value range assigned to the node, and a lookup table. The first intermediate hash result is obtained from a flow tuple of the first packet, and the lookup table comprises an entry indicating a mapping between the particular port number and a second intermediate hash result. A second packet, in which the source port is the set to the substitute port number, is transmitted to a recipient indicated in the first packet.