Browse Prior Art Database

Discovery Route Bridging in a Frame Relay Wide Area Network

IP.com Disclosure Number: IPCOM000117861D
Original Publication Date: 1996-Jun-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 139K

Publishing Venue

IBM

Related People

Brooks, WB: AUTHOR [+2]

Abstract

Discovery Source Route Bridging provides a hybrid approach to the task of bridging in a frame relay Wide Area Network (WAN) environment. With Discovery Source Route Bridging (DSRB), segment numbers in use on various virtual circuits in a frame relay network are discovered rather than explicitly configured. This article discusses the implementation of DSRB in a frame relay environment although the concepts may be extensible to other similar WAN environments.

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Discovery Route Bridging in a Frame Relay Wide Area Network

      Discovery Source Route Bridging provides a hybrid approach to
the task of bridging in a frame relay  Wide Area Network (WAN)
environment.  With Discovery Source Route Bridging (DSRB), segment
numbers in use on various virtual circuits in a frame relay network
are discovered rather than explicitly configured.  This article
discusses the implementation of DSRB in a frame relay  environment
although the concepts may be extensible to other similar WAN
environments.

      Source route bridging was originally designed for a Token Ring
Local Area Network (LAN) environment.  Remote source route bridging
extends the source route bridging concept to a WAN environment.  When
implementing remote source route bridging, many bridges allow only
one segment (or ring) number to be configured for the entire frame
relay network.  The approach of other bridges is to require each
virtual circuit  in the frame relay network to be configured with a
different segment number.  Discovery Source Route Bridging (DSRB)
provides the ability to view the frame relay  WAN from both
approaches.  With DSRB, segment numbers in use on various virtual
circuits in the WAN may be discovered rather than explicitly
configured.  Thus, DSRB provides an approach that gives some dynamic
configurability to the bridge and allows the bridge to provide
greater network connectivity when the frame relay network  is not
fully meshed.

      Discovery Source Route Bridging combines the ease of
customization of treating the frame relay network  as a single
segment with the flexibility of treating each virtual circuit as a
separate segment.  In a bridge implementing DSRB, each frame relay
interface is configured as one segment number.  The use of other
segment numbers on each of the virtual circuits for which bridging is
supported across a particular frame relay interface allows for the
use of discovered segments.  Any frames which are received on one
segment may be bridged out any other segment known to the bridge,
regardless of whether the other segment describes a LAN or another
virtual circuit on the same frame relay interface.

      Each physical bridge interface (physical bridge port) is also
viewed on a logical bridge port basis.  Each logical bridge port
corresponds to a single segment number.  Each frame relay interface
is configured to use single segment number.  This segment number is
the default segment number used for all traffic received or
transmitted across the frame relay interface.  Thus, the logical
bridge port associated with that segment number is referred to as a
configured logical bridge port.

      As traffic is received across various virtual circuits, the use
of other segment numbers on the virtual circuits become known.
Instead of discarding frames with mismatched segment numbers, new
logical ports  are created for the newly discovered segment numbers.
The newl...