MAPOS Version 1 Assigned Numbers
The registry of Protocol field values used by MAPOS version 1, a multiple-access link layer for SONET/SDH.
Maruyama, M. and K. Murakami, "MAPOS Version 1 Assigned Numbers", RFC 2172, DOI 10.17487/RFC2172, June 1997, <https://www.rfc-editor.org/info/rfc2172>.
@misc{rfc2172,
series = {Request for Comments},
number = 2172,
howpublished = {RFC 2172},
publisher = {RFC Editor},
doi = {10.17487/RFC2172},
url = {https://www.rfc-editor.org/info/rfc2172},
author = {M. Maruyama and K. Murakami},
title = {{MAPOS Version 1 Assigned Numbers}},
pagetotal = 3,
year = 1997,
month = jun,
} RFC text
Contents
Network Working Group M. Maruyama
Request for Comments: 2172 K. Murakami
Category: Informational NTT Laboratories
June 1997
MAPOS Version 1 Assigned Numbers
Status of this Memo
This memo provides information for the Internet community. This memo
does not specify an Internet standard of any kind. Distribution of
this memo is unlimited.
Authors' Note
This memo documents the parameters used in the Multiple Access
Protocol over SONET/SDH Version 1. This document is NOT the product
of an IETF working group nor is it a standards track document. It
has not necessarily benefited from the widespread and in-depth
community review that standards track documents receive.
Abstract
This document describes the protocol parameters used in the Multiple
Access Over SONET/SDH (MAPOS) version 1. MAPOS is a link layer
protocol and provides multiple access capability over SONET/SDH
links.
1. Introduction
Multiple Access Protocol over SONET/SDH (MAPOS) [1] is a high-speed
link-layer protocol that provides multiple access capability over
SONET(Synchronous Optical Network)/SDH(Synchronous Digital
Hierarchy)[2][3][4][5]. Its frame format is based on the HDLC-like
framing [6] for PPP. A component called "Frame Switch" [1] allows
multiple nodes to be connected together in a star topology to form a
LAN. Using long haul SONET/SDH links, the nodes on such a "SONET-LAN"
can span over a wide geographical area. The Internet Protocol (IP)
[7] datagrams are transmitted in MAPOS HDLC frames [8].
This document describes the protocol parameters used in MAPOS version
1 [1].
2. Protocol Field Assignments
The MAPOS Version 1 Data Link Layer [1] contains a 16 bit Protocol
field to identify the the encapsulated protocol. The Protocol field
is consistent with the ISO 3309 (HDLC) extension mechanism for
address fields. All protocol numbers MUST be assigned such that the
least significant bit of the most significant octet equals "0", and
the least significant bit of the least significant octet equals "1".
Assigned MAPOS Protocol Numbers
Value (in hex) Protocol Name
0001-001F Not Used - reserved
0021 MAPOS Version 1 Internet Protocol Version 4 [8]
0023-FCFF Not Used - reserved
FE01 MAPOS Version 1 Address Resolution Protocol (ARP[8])
FE03 MAPOS Version 1 Node Switch Protocol (NSP[9])
FE05 MAPOS Version 1 Switch Switch Protocol (SSP[10])
FE07-FEFF Not Used - reserved
References
[1] Murakami, K. and M. Maruyama, "MAPOS - Multiple Access Protocol
over SONET/SDH, Version 1," RFC-2171, June 1997.
[2] CCITT Recommendation G.707: Synchronous Digital Hierarchy Bit
Rates (1990).
[3] CCITT Recommendation G.708: Network Node Interface for
Synchronous Digital Hierarchy (1990).
[4] CCITT Recommendation G.709: Synchronous Multiplexing Structure
(1990).
[5] American National Standard for Telecommunications - Digital
Hierarchy - Optical Interface Rates and Formats Specification,
ANSI T1.105-1991.
[6] Simpson, W., editor, "PPP in HDLC-like Framing," RFC-1662,
July 1994.
[7] Postel, J., "Internet Protocol (IP)," RFC-791, September 1981.
[8] Murakami, K. and M. Maruyama, "IPv4 over MAPOS Version 1,"
RFC-2176, June, 1997.
[9] Murakami, K. and M. Maruyama, "A MAPOS version 1 Extension -
Node Switch Protocol," RFC-2173, June, 1997.
[10] Murakami, K. and M. Maruyama, "A MAPOS version 1 Extension -
Switch Switch Protocol," RFC-2174, June, 1997.
Acknowledgements
The authors would like to acknowledge the contributions and
thoughtful suggestions of John P. Mullaney, Clark Bremer, Masayuki
Kobayashi, Paul Francis, Toshiaki Yoshida, and Takahiro Sajima.
Author's Address
Mitsuru Maruyama
NTT Software Laboratories
3-9-11, Midori-cho
Musashino-shi
Tokyo-180, Japan
E-mail: mitsuru@ntt-20.ecl.net
Ken Murakami
NTT Software Laboratories
3-9-11, Midori-cho
Musashino-shi
Tokyo-180, Japan
E-mail: murakami@ntt-20.ecl.net
ISO Plain Language
On this page
§1What MAPOS Is
MAPOS (Multiple Access Protocol over SONET/SDH) is a high-speed link-layer protocol that provides multiple access over SONET (Synchronous Optical Network) and SDH (Synchronous Digital Hierarchy) links. Its frame format is based on the HDLC-like framing used for PPP. A component called a Frame Switch lets multiple nodes connect in a star topology to form a LAN, and over long-haul SONET/SDH links such a network can span a wide geographic area. IP datagrams are transmitted in MAPOS HDLC frames.
The authors' note says the document is not the product of an IETF working group, is not a standards-track document, and has not necessarily had the in-depth community review that standards-track documents receive. It documents the parameters of MAPOS version 1.
MAPOS lets several computers share one fast fiber-optic line through a central switch. This memo is only a lookup table of the numeric tags its frames use.
§2The Protocol Field Rule
The MAPOS version 1 data link layer contains a 16-bit Protocol field that identifies the encapsulated protocol. The field follows the ISO 3309 (HDLC) extension mechanism for address fields. All protocol numbers MUST be assigned so that the least significant bit of the most significant octet is 0 and the least significant bit of the least significant octet is 1.
Every protocol tag follows one bit pattern, so a receiver always knows that the first byte is not the end and the last byte is. This keeps the numbers unambiguous.
§3Assigned Protocol Numbers
The memo gives the assigned values in hexadecimal. 0021 is MAPOS Version 1 Internet Protocol Version 4, defined in RFC 2176. FE01 is the Address Resolution Protocol. FE03 is the Node Switch Protocol, defined in RFC 2173. FE05 is the Switch Switch Protocol, defined in RFC 2174. The ranges 0001-001F, 0023-FCFF and FE07-FEFF are marked not used and reserved.
A few numbers are taken: one for internet data, one for finding a machine's address, and two for jobs the switches do. The rest are saved for later use.
- 0001-001FReserved — Not used.
- 0021IPv4 — MAPOS Version 1 Internet Protocol Version 4.
- 0023-FCFFReserved — Not used.
- FE01ARP — MAPOS Version 1 Address Resolution Protocol.
- FE03NSP — MAPOS Version 1 Node Switch Protocol.
- FE05SSP — MAPOS Version 1 Switch Switch Protocol.
- FE07-FEFFReserved — Not used.