Path MTU discovery
RFC 1191, “Path MTU discovery”, is a Draft Standard document published in November 1990 by J. Mogul, S. Deering. It obsoletes RFC 1063. The canonical text is published by the RFC Editor.
Abstract
This memo describes a technique for dynamically discovering the maximum transmission unit (MTU) of an arbitrary internet path. It specifies a small change to the way routers generate one type of ICMP message. For a path that passes through a router that has not been so changed, this technique might not discover the correct Path MTU, but it will always choose a Path MTU as accurate as, and in many cases more accurate than, the Path MTU that would be chosen by current practice. [STANDARDS-TRACK]
What “Draft Standard” means
A historical maturity level (retired in 2011) that sat between Proposed Standard and Internet Standard and required multiple interoperable implementations.
The canonical text of RFC 1191 is hosted at rfc-editor.org. Available in TXT,HTML.
- RFC 1190 Experimental Internet Stream Protocol: Version 2
- RFC 1192 Commercialization of the Internet summary report
- RFC 1189 Common Management Information Services and Protocols for the Internet
- RFC 1193 Client requirements for real-time communication services
- RFC 1188 Proposed Standard for the Transmission of IP Datagrams over FDDI Networks
- RFC 1194 Finger User Information Protocol
- RFC 1187 Bulk Table Retrieval with the SNMP
- RFC 1195 Use of OSI IS-IS for routing in TCP/IP and dual environments