Browse Prior Art Database

Directory Caching Method Based On Bind Monitoring

IP.com Disclosure Number: IPCOM000120574D
Original Publication Date: 1991-May-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 2 page(s) / 103K

Publishing Venue

IBM

Related People

Hoberecht, VL: AUTHOR [+2]

Abstract

Disclosed is a directory caching method to improve performance of APPN and SNA subarea network interconnections that applies to sessions across the Type 2.1 boundary function initiated by an APPN-resident LU. By monitoring BIND and BIND response messages, an APPN network node attached to an Type 2.1 boundary function (a BANN) learns about LUs outside its APPN network. This enables the BANN to reply explicitly to APPN directory searches for such LUs without predefinition at the BANN. This decreases subsequent session set-up time by reducing the number of broadcast searches in the APPN network. Only the BANN need be upgraded, and an existing wildcard definition at the BANN, representing connectivity to a subarea network, is preserved.

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This is the abbreviated version, containing approximately 52% of the total text.

Directory Caching Method Based On Bind Monitoring

      Disclosed is a directory caching method to improve
performance of APPN and SNA subarea network interconnections that
applies to sessions across the Type 2.1 boundary function initiated
by an APPN-resident LU.  By monitoring BIND and BIND response
messages, an APPN network node attached to an Type 2.1 boundary
function (a BANN) learns about LUs outside its APPN network.  This
enables the BANN to reply explicitly to APPN directory searches for
such LUs without predefinition at the BANN.  This decreases
subsequent session set-up time by reducing the number of broadcast
searches in the APPN network.  Only the BANN need be upgraded, and an
existing wildcard definition at the BANN, representing connectivity
to a subarea network, is preserved.

      Advanced peer-to-peer networking (APPN) and sub-area SNA
networking (sub-area) use different but related protocols.  A network
service access port (logical unit or LU) in an APPN network can
communicate with a compatible LU in a subarea network after a
connection (session) is established between them.  The session
activation message is called BIND and it requires a definite reply,
either positive or negative.  BIND carries the LU-name of the target
LU.

      Sub-area protocols require predefinition of all LUs, including
those in an attached APPN network, with respect to a fixed hierarchy
of nodes and links.  APPN allows LUs to move dynamically with respect
to a peer network topology. Both protocols require assignment of a
unique name for each LU in the combined APPN/sub-area network.  A
link connecting an APPN network and a sub-area network is called an
interconnecting link.  For each APPN network, the number of
interconnecting links is limited to one.  An LU in the APPN network
is called an APPN LU.  An LU outside a given APPN network is called a
sub-area LU.  An APPN node that provides directory services to other
APPN nodes is called a network node.

      APPN protocols obtain the location of partner LUs dynamically
using Find and Found messages before sending BIND.  The Find message
may be broadcast (if the partner's location is unknown) or point-to-
point (to confirm the partner's location, when known).  A broadcast
Find message is forwarded from node to node, searching all the
network nodes in an APPN network (including all BANNs).  Every node
receiving a Find message must respond.  The reply can be positive
(indicating that the target was found) or negative (indicating that
th...