OPTIMIZED PATH MAXIMUM TRANSMISSION UNIT DISCOVERY

摘要

Embodiments of the present invention provide path MTU discovery of a network path, such as an IPv4 network. According to various embodiments of the invention, a node receives a packet at a node along the network path between a source node and a destination node, compares a MTU size of a next hop along the network path with the size of the packet, responsive to the MTU size of the next hop along the network path being less than the size of the packet, a DF flag being set to not allow fragmentation, a RC flag being set to identify that a portion of the packet is reserved for PMTU size, and a PMTU bit being set to positive, truncates the packet to the MTU size of the next hop, stores the MTU size in the portion of the packet reserved for PMTU size, and forwards the packet.

主权项

1. A method for path maximum transmission unit (PMTU) discovery, the method comprising:
receiving a packet at a node along a network path between a source node and a destination node; comparing a maximum transmit unit (MTU) size of a next hop along the network path with the size of the packet; and responsive to the MTU size of the next hop along the network path being less than the size of the packet and identifying a “do not fragment” (DF) flag being set to not allow fragmentation:
responsive to identifying a recycled (RC) flag being set to identify that a portion of the packet is reserved for PMTU size, and a PMTU bit being set to positive:
truncating the packet to the MTU size of the next hop;storing the MTU size in the portion of the packet reserved for PMTU size; andforwarding the packet to the next hop.