Browse Prior Art Database

Local Network Monitoring to Populate Access Agent Directory

IP.com Disclosure Number: IPCOM000105815D
Original Publication Date: 1993-Sep-01
Included in the Prior Art Database: 2005-Mar-20
Document File: 4 page(s) / 186K

Publishing Venue

IBM

Related People

Derby, JH: AUTHOR [+7]

Abstract

Disclosed are improvements in the intelligent bridging of local area networks (LANs) by a wide area network (WAN) such as the type disclosed in [2]. The improvements minimize network administration costs by enabling the network to dynamically learn the WAN network addresses through which individual LAN stations may be reached, after installation or relocation. The improvements also minimize connection setup time, and minimize flooding broadcasts between WAN-interconnected LANs. This invention also takes advantage of fast-packet switching capabilities such as those disclosed in [1], if available.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 30% of the total text.

Local Network Monitoring to Populate Access Agent Directory

      Disclosed are improvements in the intelligent bridging of local
area networks (LANs) by a wide area network (WAN) such as the type
disclosed in [2].  The improvements minimize network administration
costs by enabling the network to dynamically learn the WAN network
addresses through which individual LAN stations may be reached, after
installation or relocation.  The improvements also minimize
connection setup time, and minimize flooding broadcasts between
WAN-interconnected LANs.  This invention also takes advantage of
fast-packet switching capabilities such as those disclosed in [1], if
available.

      The following terms apply throughout this article.  "Resources"
are data sources and sinks, external to the WAN, whose data flows
across the WAN on WAN transport- and network-layer connections.  (A
LAN end station is an example of a resource.)  The information used
by the WAN to identify a resource includes the resource address and
the resource type.  "Directory service" is a set of WAN protocols to
query a distributed database, in order to map a resource to the WAN
network address through which it can be accessed.  "Client" and
"server" refer to the sender and receiver of such queries,
respectively.  Some queries are multicasts (i.e., a transmission by
one sender to multiple receivers).  When a query is a multicast, more
than one server can receive it and, possibly, respond.

      "Access agents" provide standard interfaces or points of
attachment where protocol-specific traffic enters a shared WAN
backbone.  LAN access agents contain one or more protocol agents
responsible for a particular LAN protocol, e.g., 802.2, TCP.  Access
agents send and receive queries about LAN-resident resources using
the WAN directory protocols.  An access agent only supports queries
for resources of the type that its associated protocol agent(s) can
provide access to.

      This invention applies to the environment where an access agent
situated at the interface between a LAN and a WAN performs an
"intelligent bridging" function, described below, to suppress the
so-called "broadcast storms" that can occur in large bridged LANs
when broadcast messages are unconditionally forwarded to all LAN
segments.  The access agent inspects LAN traffic, then invokes
distributed WAN directory protocols among access agents to determine
the WAN network address through which a target LAN station may be
reached.  Once the target is located, the access agent determines how
best to utilize the WAN transport facilities to transparently enable
communication between the source and sink.

      Some background about the WAN directory service protocols is
necessary for understanding this invention.  Each access agent
maintains a directory of resources containing multiple entries, one
per resource.  Each entry lists one resource, giving its resource
address, resource type, address pr...