1 /* $NetBSD: README.hdlc,v 1.5 2003/01/04 23:43:06 wiz Exp $ */
2
3 /*
4 * Copyright (c) University of British Columbia, 1984
5 *
6 * @(#)README.hdlc 8.1 (Berkeley) 6/10/93
7 *
8 * X.25 HDLC DATA LINK LEVEL:
9 *
10 *
11 * This module implements the Link Level of the Open Systems Interconnect
12 * Model. The implementation is based on the ISO High-Level Data Link
13 * Control (HDLC). These procedures subscribe to the principles of the
14 * ISO-Class of Procedures for point-to-point. These procedures implement
15 * two-way asynchronous balanced mode (LAPB) as recommented by the CCITT.
16 *
17 * The HDLC protocol layer interface consists of the following procedures:
18 * Hd_init (pr_init)
19 * Hd_output (pr_output)
20 * Hd_input (pr_input)
21 * Hd_timer (pr_slowtimo)
22 *
23 * Note: Supervisory commands RR, RNR and REJ are not transmitted by this
24 * station.
25 *
26 * This station never enters a busy (RNR) condition.
27 *
28 * The "Generate_rr" variable can be set to FALSE. This means that
29 * we NEVER send an RR. This works just fine if the network level
30 * is X.25 packet protocol -- which it is.
31 *
32 * Currently, this is only a DTE implementation.
33 *
34 * Think about:
35 * If the remote is busy, no iframes are sent. The remote sends a RR
36 * to clear this condition. However, this RR may be damaged, causing
37 * a possible deadlock. A solution is to poll with iframe (P(S)==P(R)
38 * of RNR) indefinitly.
39 *
40 *
41 * Date: February 1984
42 *
43 * Author: Gerald W. Neufeld
44 *
45 * Installation: Department of Computer Science
46 * University of British Columbia
47 * Vancouver, BC, CANADA.
48 *
49 * History:
50 *
51 *
52 */
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