Patent ID: 8005968

Claim:
One or more computer storage media having computer-useable instructions embodied thereon for performing a method for determining a destination host path maximum transmission unit (PMTU), the method comprising: from a source host, accessing one or more MTU lookup tables each having a plurality of entries, wherein at least one MTU lookup table includes entries for destination hosts, subnets, and networks, each entry having a corresponding entry MTU value; upon determining that one or more internet protocol (IP) address subnet prefixes of a destination host are entries in the one or more MTU lookup tables, selecting the corresponding entry MTU value of one of the entries to use as the PMTU between the source host and the destination host by: when an IP address subnet prefix of the destination host is an entry in only one lookup table, setting the PMTU between the source host and destination host to the corresponding entry MTU value; and when an IP address subnet prefix of the destination host is an entry in a plurality of lookup tables: determining a preferred entry type of either local or network, and setting the PMTU between the source host and destination host to the entry MTU value of the entry in the plurality of lookup tables that is the preferred entry type and is the most specific IP address subnet prefix, wherein the IP address subnet prefixes of the destination host specify one of: the destination host, a subnet in which the destination host is located, or a network in which the destination host is located; and upon determining that an IP address subnet prefix of the destination host is not an entry in the one or more lookup tables, setting the PMTU between the source host and the destination host to a default value.