RFC 1307 (rfc1307) - Page 2 of 13


Dynamically Switched Link Control Protocol



Alternative Format: Original Text Document



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