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