Browse Prior Art Database

Data Link Switching: Switch-to-Switch Protocol (RFC1434)

IP.com Disclosure Number: IPCOM000002262D
Original Publication Date: 1993-Mar-01
Included in the Prior Art Database: 2001-Nov-09
Document File: 34 page(s) / 80K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

R. Dixon: AUTHOR [+2]

Abstract

This RFC describes IBM's support of Data Link Switching over TCP/IP. The RFC is being distributed to members of the Internet community in order to solicit their reactions to the proposals contained in it. While the issues discussed may not be directly relevant to the research problems of the Internet, they may be interesting to a number of researchers and implementors.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 5% of the total text.

Network Working Group                                          R. Dixon

Request for Comments: 1434                                     D. Kushi

                                                                    IBM

                                                             March 1993

             Data Link Switching: Switch-to-Switch Protocol

Status of this Memo

   This memo provides information for the Internet community.  It does

   not specify an Internet standard.  Distribution of this memo is

   unlimited.

Abstract

   This RFC describes IBM's support of Data Link Switching over TCP/IP.

   The RFC is being distributed to members of the Internet community in

   order to solicit their reactions to the proposals contained in it.

   While the issues discussed may not be directly relevant to the

   research problems of the Internet, they may be interesting to a

   number of researchers and implementors.

   Any questions or comments relative to the contents of this RFC should

   be sent to the following Internet address: dlsw@ralvma.vnet.ibm.com.

Table of Contents

   1. Introduction                                                     2

   2. Overview                                                         2

   3. Transport Connection                                             4

      3.1. SSP Frame Formats                                           5

      3.2. Address Parameters                                          8

      3.3. Message Types                                              10

   4. Protocol Specification                                          11

      4.1. Protocol Flow Diagrams                                     11

           4.1.1. Connect Protocols                                   11

           4.1.2. Link Restart Protocols                              13

           4.1.3. Disconnect Protocols                                15

      4.2. DLS State Machine                                          16

           4.2.1 Data Link Switch States                              16

           4.2.2 State Transition Tables                              21

      4.3. NetBIOS Datagrams                                          30

   Acknowledgments                                                    32

   References                                                         32

   Security Considerations                                            32

   Authors' Addresses                                                 33

Dixon & Kushi                                                   [Page 1]

RFC 1434             DLS: Switch-to-Switch Protocol           March 1993

1. Introduction

   Data Link Switching (DLS) is a forwarding mechanism for the IBM SNA

   and IBM NetBIOS protocols.  It does not provide full routing, but

   instead provides switching at the Data Link layer and encapsulation

   in TCP/IP for transport over the Internet.  This memo documents the

   Switch-to-Switch Protocol (SSP) that is used between IBM 6611 Network

   Processors.

   Today, the IBM 6611 supports SNA (PU 2 and PU 4) systems and NetBIOS

   systems attached to token-ring networks, as well as SNA (PU 2)

   systems attached to SDLC links.  For the later case, the SDLC

   attached systems are provided with a LAN appearance within the IBM

   6611.  For the LAN attached systems, the IBM 6611 appears as a

   source-routing bridge.  Remote systems that are accessed through the

   IBM 6611 appear as systems attached to an adjacent ring.  This ring

   is a virtual ring that is manifested within each IBM 6611.

2. Overview

   Data Link Switching was developed to provide support for SNA and

   NetBIOS in multi-protocol routers.  Since SNA and NetBIOS are

   basically connection oriented protocols, the Data Link Control

   procedure that they use on the LAN is IEEE 802.2 Logical Link Control

   (LLC) Type 2.  Data Link Switching also accommodates SNA protocols

   over WAN links via the SDLC protocol.

   IEEE 802.2 LLC Type 2 was designed with the assumption that the

   network transit delay would be small and predictable (i.e., a local

   LAN).  Therefore the LLC elements of procedure use a fixed timer for

   detecting lost frames.  When bridging is used over wide area lines

   (especially at lower speeds), the network delay is larger and it can

   vary greatly based...