Browse Prior Art Database

Dynamic Linkages to Open Up Communications

IP.com Disclosure Number: IPCOM000109490D
Original Publication Date: 1992-Sep-01
Included in the Prior Art Database: 2005-Mar-24
Document File: 4 page(s) / 191K

Publishing Venue

IBM

Related People

Dick, RL: AUTHOR [+4]

Abstract

A method for separating communications transport and networking protocols is disclosed. Dynamic linkages between the transport and network objects are completed at connection establishment time rather than the usual static nature of these linkages. This is achieved through the use of a neutral object called the Remote Network Index.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 43% of the total text.

Dynamic Linkages to Open Up Communications

       A method for separating communications transport and
networking protocols is disclosed.  Dynamic linkages between the
transport and network objects are completed at connection
establishment time rather than the usual static nature of these
linkages.  This is achieved through the use of a neutral object
called the Remote Network Index.

      The separation of network and transport functions is transposed
on the Open Systems Interconnection (OSI) model below.

      NOTE: The terms Transport Driver and Network Driver in Fig. 1
refer to the programming routines and data associated with the
separate functional distributions.

      An example of the Remote Network Index follows along with short
descriptions of all the objects involved in this separation
technique:

      NOTE: The objects described here are active objects that
provide methods as well as data.
o  Local Network - Describes the local system port (physical,
datalink) attachment to the network.
o  Remote Network - Describes the remote system port (physical,
datalink) attachment to the network.
o  Initial Transport - Used to attach a Network object instance to
the proper upper layer protocol.  It will swap to the
protocol-specific Remote System object instance as soon as the data
received identifies the correct object (note that this process will
be different for each Transport Driver because some transports will
require more, some less, data to identify the Remote System to swap
to).
o  Remote System - Describes the remote system characteristics
(transport protocol dependent).
o  Remote Network Index - Entries tie the Remote Network instance(s)
to the upper layer protocol(s) running over them (refer to Fig. 2).
Notes on the Remote Network Index:
o  There is one Remote Network Index per Local Network type,
regardless of the number of objects of that type on the system.
o  A single Remote Network object can be registered more than once so
that multiple Initial Transports can be tied to one Remote Network
object.
o  Entry creation takes place when the Remote Network objects are
varied on.
o  Separation of layers is maintained by the Remote Network object
doing a "Query" of the Initial Transport to obtain the value for the
Key Field (e.g., Protocol ID for an X.25 Remote Network).
o  Initial Transport objects, associated with the transports, may be
found in the Transport Registration Table (refer to Fig. 3).

      To separate the transport from the network, we had to solve one
overriding problem.  When a packet comes in to a Local Network
object, how does that object know which upper level protocol that
packet is destined for without putting transport configuration in the
Local Network object?

      The answer turned out to be a neutral object (Remote Network
Index).  This is where we could tie network-specific configuration to
the transport-specific data.  The key that ties the two together...