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 and responsive to the packet supporting path MTU discovery, the node 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 of a network path in a network, the method comprising:
generating an Internet Control Message Protocol (ICMP)-compatible echo request packet, the ICMP-compatible packet comprising:
an ICMP echo request packet with a “do not fragment” (DF) flag being set to indicate to not allow fragmentation of the ICMP-compatible packet, a recycled (RC) flag being set to indicate that an identifier in the ICMP-compatible packet has a special meaning, a PMTU discovery flag in the ICMP-compatible packet that indicates that this packet can be used for PMTU discovery, and a portion of the ICMP-compatible packet being reserved for PMTU size; and transmitting the ICMP-compatible echo request packet to a device on the network path.