Abstract: A local system issues an ICMP echo request packet with a size based on an initial PMTU value corresponding to that of the local system's interface MTU. When an ICMP needfrag error packet is received by the local system, this signifies that the initial PMTU value was too large for packets of corresponding size to be transmitted through the Internet without fragmentation. The value is accordingly decreased by the local system and a next ICMP echo request packet transmitted through the Internet. The process iterates until an ICMP echo request packet is successfully transmitted through the Internet to a target system. In response thereto, the target system transmits an ICMP echo response packet back through the Internet to the local system, thereby indicating that the last-sent ICMP echo request packet from the local system had the correct PMTU value which is thereafter assumed to be the correct PMTU.

Abstract: A local system issues an ICMP echo request packet with a size based on an initial PMTU value corresponding to that of the local system's interface MTU. When an ICMP needfrag error packet is received by the local system, this signifies that the initial PMTU value was too large for packets of corresponding size to be transmitted through the Internet without fragmentation. The value is accordingly decreased by the local system and a next ICMP echo request packet transmitted through the Internet. The process iterates until an ICMP echo request packet is successfully transmitted through the Internet to a target system. In response thereto, the target system transmits an ICMP echo response packet back through the Internet to the local system, thereby indicating that the last-sent ICMP echo request packet from the local system had the correct PMTU value which is thereafter assumed to be the correct PMTU.

Abstract: An information handling system includes a number of stations connected in a network configuration, each station including a processor, a storage and an I/O controller, where the processor operates under control of an operating system control program which is divided into a user (application) space and a kernel (system) space, the kernel may include a protocol layer interfacing the user application to a DLPI in the kernel, a DLPI which interfaces between the protocol module and a device driver interface, a device driver and a hardware device for connecting the station to the network. When data is to be received by a station from the network, the following steps are performed in the DLPI: recognize the network interface type (FDDI, Ethernet, Token Ring, etc.