Dynamically Switched Link Control Protocol
RFC 1307
Document | Type |
RFC - Experimental
(March 1992; No errata)
Was draft-young-linkcontrol (individual)
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Authors | Andy Nicholson , Jeff Young | ||
Last updated | 2013-03-02 | ||
Stream | Legacy stream | ||
Formats | plain text html pdf htmlized (tools) htmlized bibtex | ||
Stream | Legacy state | (None) | |
Consensus Boilerplate | Unknown | ||
RFC Editor Note | (None) | ||
IESG | IESG state | RFC 1307 (Experimental) | |
Telechat date | |||
Responsible AD | (None) | ||
Send notices to | (None) |
Network Working Group J. Young Request for Comments: 1307 A. Nicholson Cray Research, Inc. March 1992 Dynamically Switched Link Control Protocol Status of this Memo This memo defines an Experimental Protocol for the Internet community. Discussion and suggestions for improvement are requested. Please refer to the current edition of the "IAB Official Protocol Standards" for the standardization state and status of this protocol. Distribution of this memo is unlimited. Abstract This memo describes an experimental protocol developed by a project team at Cray Research, Inc., in implementing support for circuit- switched T3 services. The protocol is used for the control of network connections external to a host, but known to the host. It is documented here for the benefit of others who may wish to perform further research. While working with circuit-switched T3 networks, developers at Cray Research, Inc., defined a model wherein a host would generate control messages for a network switch. This work is described in RFC 1306, "Experiences Supporting By-Request Circuit-Switched T3 Networks". In order to simplify the model it was decided that the inconsistencies of switch control should be hidden from the host generating the control messages. To that end, a protocol was defined and implemented. This RFC documents the Dynamically Switched Link Control Protocol (DSLCP), which is used for creation and control of downstream network links by a host. 1.0 INTRODUCTION The Dynamically Switched Link Control Protocol (DSLCP) allows a host with knowledge of a special downstream network link to issue messages to control the status of that link. This document describes the functions of the DSLCP to control external network connections. Young & Nicholson [Page 1] RFC 1307 Dynamically Switched Link Control Protocol March 1992 1.1 Motivation Circuit Switched Networks are becoming available to the Internet community. These networks are made available by requesting a connection through a switch. Normally circuit switched network links are disconnected, and their prohibitive cost suggests that it is very costly to leave them connected at all times. Internet users and hosts wish to send data over a circuit switched networks, but only connect the network links when a transport connection is to be established. While it would be possible to use packet routers to identify the need for switching a connection on and off, only the transport provider can positively identify the beginning and end of a transport session. There must be a mechanism to activate and deactivate the link at the beginning and end of a transport session. The DSLCP assumes that a transport provider has knowledge of a downstream link which must be setup before data transfer may take place. However, the details of link setup may vary by the type of link (circuit-switched or other), specific hardware, or administrative differences. The DSLCP hides these details from the transport provider by offering a simple request/release model of link preparation. The model assumes an entity in control of the link which handles the details of connection preparation while responding to the DSLCP commands of the transport provider. This entity is called the link controller. The DSLCP allows internet hosts to dynamically change the fabric of the internet by sending messages through the internet in advance of data which is to travel across the newly created links. 1.2 Scope DSLCP is intended to provide an interface between transport providers and arbitrary network links requiring creation, control, setup, or conditioning before data communications may take place. 1.3 Interfaces There are no specific user level interfaces to DSLCP, although they are not precluded. Link control is a function of the network layer, initiated by requests from the transport provider. A DSLCP transaction is defined as a transport provider communicating with a link controller for the duration of transport session. A network path between the host providing transport services and the link controller must exist in advance of the DSLCP transaction. Young & Nicholson [Page 2] RFC 1307 Dynamically Switched Link Control Protocol March 1992 Either party to an DSLCP transaction may asynchronously generate messages. 1.4 Operation The purpose of the DSLCP is to allow a transport provider to request the setup of a downstream network link so that data transfer may takeShow full document text