Multiprotocol Interconnect on X.25 and ISDN in the Packet Mode (RFC1356)
Original Publication Date: 1992-Aug-01
Included in the Prior Art Database: 2019-Feb-11
Internet Society Requests For Comment (RFCs)
A. Malis: AUTHOR [+2]
This document specifies the encapsulation of IP and other network layer protocols over X.25 networks, in accordance and alignment with ISO/IEC and CCITT standards. It is a replacement for RFC 877, "A Standard for the Transmission of IP Datagrams Over Public Data Networks" . [STANDARDS-TRACK]
Network Working Group A. Malis Request for Comments: 1356 BBN Communications Obsoletes: RFC 877 D. Robinson Computervision Systems Integration R. Ullmann Process Software Corporation August 1992
Multiprotocol Interconnect on X.25 and ISDN in the Packet Mode
Status of this Memo
This RFC specifies an IAB standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "IAB Official Protocol Standards" for the standardization state and status of this protocol. Distribution of this memo is unlimited.
This document specifies the encapsulation of IP and other network layer protocols over X.25 networks, in accordance and alignment with ISO/IEC and CCITT standards. It is a replacement for RFC 877, "A Standard for the Transmission of IP Datagrams Over Public Data Networks" .
It was written to correct several ambiguities in the Internet Standard for IP/X.25 (RFC 877), to align it with ISO/IEC standards that have been written following RFC 877, to allow interoperable multiprotocol operation between routers and bridges over X.25, and to add some additional remarks based upon practical experience with the specification over the 8 years since that RFC.
The substantive change to the IP encapsulation is an increase in the allowed IP datagram Maximum Transmission Unit from 576 to 1600, to reflect existing practice.
This document also specifies the Internet encapsulation for protocols, including IP, on the packet mode of the ISDN. It applies to the use of Internet protocols on the ISDN in the circuit mode only when the circuit is established as an end-to-end X.25 connection.
Malis, Robinson, & Ullmann [Page 1]
RFC 1356 Multiprotocol Interconnect on X.25 August 1992
RFC 877 was written by J. T. Korb of Purdue University, and this document follows that RFC’s format and builds upon its text as appropriate. This document was produced under the auspices of the IP over Large Public Data Networks Working Group of the IETF.
The following language conventions are used in the items of specification in this document:
o MUST -- the item is an absolute requirement of the specification. MUST is only used where it is actually required for interoperation, not to try to impose a particular method on implementors where not required for interoperability.
o SHOULD -- the item should be followed for all but exceptional circumstances.
o MAY or optional -- the item is truly optional and may be followed or ignored according to the needs of the implementor.
The words "should" and "may" are also used, in lower case, in their more ordinary senses.
RFC 877 was written to document the method CSNET and the VAN Gateway had adopted to transmit IP datagrams over X.25 networks. Its success is evident in its current wide use and the inclusion of its IP protocol identifier in ISO/IEC TR 9577, "Protocol Identification in the Network Layer" , which...