RFC 1795 (rfc1795) - Page 2 of 91
Data Link Switching: Switch-to-Switch Protocol AIW DLSw RIG: DLSw Closed Pages, DLSw Standard Version 1
Alternative Format: Original Text Document
RFC 1795 Data Link Switching April 1995
it's working groups send email to:
Information regarding all of the AIW working groups and the work they
are producing can be obtained by copying, via anonymous ftp, the file
aiwinfo.psbin or aiwinfo.txt from the Internet host
networking.raleigh.ibm.com, located in directory aiw.
NOTE 2: These mailing lists and addresses are subject to change.
1. Introduction
Data Link Switching (DLSw) is a forwarding mechanism for the IBM SNA
(Systems Network Architecture) and IBM NetBIOS (Network Basic Input
Output Services) protocols. This memo documents the Switch-to-Switch
Protocol (SSP) that is used between Data Link Switches. This
protocol does not provide full routing, but instead provides
switching at the SNA Data Link layer (i.e., layer 2 in the SNA
architecture) and encapsulation in TCP/IP for transport over the
Internet. This RFC documents the frame formats and protocols for
multiplexing data between Data Link Switches. The initial
implementation of SSP uses TCP as the reliable transport between Data
Link Switches. However, other transport connections such as OSI TP4
could be used in the future.
A Data Link Switch (abbreviated also as DLSw in this document) can
support SNA (Physical Unit (PU) 2, PU 2.1 and PU 4) systems and
optionally NetBIOS systems attached to IEEE 802.2 compliant Local
Area Networks, as well as SNA (PU 2 (primary or secondary) and PU2.1)
systems attached to IBM Synchronous Data Link Control (SDLC) links.
For the latter case, the SDLC attached systems are provided with a
LAN appearance within the Data Link Switch (each SDLC PU is presented
to the SSP protocol as a unique MAC/SAP address pair). For the
Token-Ring LAN attached systems, the Data Link Switch appears as a
source-routing bridge. Token-Ring Remote systems that are accessed
through the Data Link Switch appear as systems attached to an
adjacent ring. This ring is a virtual ring that is manifested within
each Data Link Switch.
1.1 Backwards Compatibility with RFC 1434
This document defines significant changes to RFC 1434 and does not
state details on how to interoperate with RFC 1434 or "enhanced"
implementations (e.g., those that added enter and exit busy flow
control). It is up to the implementer to refer to RFC 1434 and/or
any other vendor's documentation in order to interoperate with a
given vendor's implementation, if interoperability with pre-AIW DLSw
RIG standards is desired.
Wells & Bartky