RFC 1613 (rfc1613) - Page 1 of 13
cisco Systems X
Alternative Format: Original Text Document
Network Working Group J. Forster
Request for Comments: 1613 G. Satz
Category: Informational G. Glick
cisco Systems, Inc.
R. Day
JANET
May 1994
cisco Systems X.25 over TCP (XOT)
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.
Table of Contents
1. Introduction....................................................1
2. Conventions.....................................................2
3. Relationship Between XOT and X.25...............................2
4. Overall Packet Format...........................................3
4.1 XOT Header....................................................4
5. TCP Connection, Port Number, and Logical Channel Numbers (LCNs).4
6. XOT Packets.....................................................5
6.1 Virtual Circuit Setup and Clearing............................5
6.2 Data and Flow Control.........................................6
6.3 Interrupt, and Reset Packets..................................8
6.4 Restart, DTE Reject, Diagnostics, and Registration............8
6.5 PVC Setup.....................................................8
7. Acknowledgments................................................12
8. Security Considerations........................................12
9. References.....................................................12
10. Authors' Addresses.............................................13
1. Introduction
It is sometimes desirable to transport X.25 over IP internets. The
X.25 Packet Level requires a reliable link level below it and
normally uses LAPB. This memo documents a method of sending X.25
packets over IP internets by encapsulating the X.25 Packet Level in
TCP packets.
TCP provides a reliable byte stream. X.25 requires that the layer
below it provide message semantics, in particular the boundary
between packets. To provide this, a small (4-byte) XOT header is
used between TCP and X.25. The primary content of this header is a
Forster, Satz, Glick & Day