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Diffstat (limited to 'sys/netccitt/README.hdlc')
| -rw-r--r-- | sys/netccitt/README.hdlc | 50 |
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diff --git a/sys/netccitt/README.hdlc b/sys/netccitt/README.hdlc new file mode 100644 index 0000000..24b5fef --- /dev/null +++ b/sys/netccitt/README.hdlc @@ -0,0 +1,50 @@ +/* + * Copyright (c) University of British Columbia, 1984 + * + * @(#)README.hdlc 8.1 (Berkeley) 6/10/93 + * + * X.25 HDLC DATA LINK LEVEL: + * + * + * This module implements the Link Level of the Open Systems Interconnect + * Model. The implementation is based on the ISO High-Level Data Link + * Control (HDLC). These procedures subscribe to the principles of the + * ISO-Class of Procedures for point-to-point. These procedures implement + * two-way asynchronous balanced mode (LAPB) as recommented by the CCITT. + * + * The HDLC protocol layer interface consists of the following procedures: + * Hd_init (pr_init) + * Hd_ouput (pr_output) + * Hd_input (pr_input) + * Hd_timer (pr_slowtimo) + * + * Note: Supervisory commands RR, RNR and REJ are not transmitted by this + * station. + * + * This station never enters a busy (RNR) condition. + * + * The "Generate_rr" variable can be set to FALSE. This means that + * we NEVER send an RR. This works just fine if the network level + * is X.25 packet protocol -- which it is. + * + * Currently, this is only a DTE implementation. + * + * Think about: + * If the remote is busy, no iframes are sent. The remote sends a RR + * to clear this condition. However, this RR may be damaged, causing + * a possible deadlock. A solution is to poll with iframe (P(S)==P(R) + * of RNR) indefinitly. + * + * + * Date: February 1984 + * + * Author: Gerald W. Neufeld + * + * Installation: Department of Computer Science + * University of British Columbia + * Vancouver, BC, CANADA. + * + * History: + * + * + */ |
