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Data Link Switching Client Access Protocol (RFC2114)

IP.com Disclosure Number: IPCOM000002667D
Original Publication Date: 1997-Feb-01
Included in the Prior Art Database: 2019-Feb-15
Document File: 22 page(s) / 25K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

S. Chiang: AUTHOR [+2]

Related Documents

10.17487/RFC2114: DOI

Abstract

This memo describes the Data Link Switching Client Access Protocol that is used between workstations and routers to transport SNA/ NetBIOS traffic over TCP sessions. This memo provides information for the Internet community. This memo does not specify an Internet standard of any kind.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 7% of the total text.

Network Working Group S. Chiang Request for Comments: 2114 J. Lee Category: Informational Cisco Systems, Inc. Obsoletes: 2106 H. Yasuda Mitsubishi Electric Corp. February 1997

Data Link Switching Client Access Protocol

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.

Abstract

This memo describes the Data Link Switching Client Access Protocol that is used between workstations and routers to transport SNA/ NetBIOS traffic over TCP sessions. Any questions or comments should be sent to dcap@cisco.com.

Table of Contents

1. Introduction ............................................ 2 2. Overview ................................................ 2 2.1 DCAP Client/Server Model ............................... 2 2.2 Dynamic Address Resolution ............................. 3 2.3 TCP Connection ......................................... 4 2.4 Multicast and Unicast (UDP) ............................ 4 3. DCAP Format ............................................. 6 3.1 General Frame Format ................................... 6 3.2 Header Format .......................................... 6 3.3 DCAP Messages .......................................... 7 3.4 DCAP Data formats ...................................... 8 3.4.1 CAN_U_REACH, I_CAN_REACH, and I_CANNOT_REACH Frames .. 8 3.4.2 START_DL, DL_STARTED, and START_DL_FAILED Frames ..... 9 3.4.3 HALT_DL, HALT_DL_NOACK, and DL_HALTED Frames ......... 13 3.4.4 XID_FRAME, CONTACT_STN, STN_CONTACTED, INFO_FRAME, FCM_FRAME, and DGRM_FRAME ............................ 14 3.4.5 DATA_FRAME ........................................... 15 3.4.6 CAP_XCHANGE Frame .................................... 16 3.4.7 CLOSE_PEER_REQ Frames ................................ 19 3.4.8 CLOSE_PEER_RSP, PEER_TEST_REQ, and PEER_TEST_RSP Frames 20 4. Protocol Flow Diagram ................................... 20 5. Acknowledgments ......................................... 22 6. References .............................................. 22

Chiang, et. al. Informational [Page 1]

RFC 2114 DCAP February 1997

1. Introduction

Since the Data Link Switching Protocol, RFC 1795, was published, some software vendors have begun implementing DLSw on workstations. The implementation of DLSw on a large number of workstations raises several important issues that must be addressed. Scalability is the major concern. For example, the number of TCP sessions to the DLSw router increases in direct proportion to the number of workstations added. Another concern is efficiency. Since DLSw is a switch-to- switch protocol, it is not efficient when implemented on workstations.

DCAP addresses the above issues. It introduces a hierarchical structure to resolve the scalability problems. All workstations are clients to the router (server) rather than peers to the router. This creates a client/server model. It also provides a more efficient protocol b...

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