Browse Prior Art Database

ATM Signaling Software Reuse through Service Access Points Remapping

IP.com Disclosure Number: IPCOM000116489D
Original Publication Date: 1995-Sep-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 4 page(s) / 177K

Publishing Venue

IBM

Related People

Aras, CM: AUTHOR [+4]

Abstract

This text describes a means to implement embedded ATM User-to-Network Interfaces (UNI) without resorting to implementing the full ATM protocol stack in an ATM network switch.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 50% of the total text.

ATM Signaling Software Reuse through Service Access Points Remapping

      This text describes a means to implement embedded ATM
User-to-Network Interfaces (UNI) without resorting to implementing
the full ATM protocol stack in an ATM network switch.

      ATM network switches transport data between input and output
ports.  These ports are usually attached to a network on one side and
either another network or an ATM end-point on the other.  The
end-point and switch communicate through the ATM UNI.  In ATM
switches, special function adapters may receive ATM traffic, change
it into other formats and route the data on other network media all
within the switch.  Examples of such integrated function adapters
include routers, ATM-to-video and ATM-to-MPEG transport converters,
etc.  These adapters may be seen as virtual ports  by the ATM switch.
Such integrated systems require the termination of the ATM data
and/or signaling protocol layers within the switch.  The software
that acts as an ATM end-point non-external to the ATM switch will be
termed as a termination agent.

      With SVC's, the call originating ATM end-point converses with
the ATM switch to indicate requests to setup and release VC's.  The
switch side of the ATM UNI may support multiple physical access
lines.  For each line, the UNI supports Service Access Points (SAP).
When a call is originated by the user, the user side session layer
uses the Q.2931 signaling protocol to send a SETUP message to its
peer in the network through the Q.SAAL (Signaling AAL) layer.  If
there are multiple service access points, the SAP identifier of the
line originating the call is propagated through each signaling layer.

      With a termination agent, certain parts of the software
normally executing in the ATM end-point hardware may execute in the
same environment as the ATM switch software for efficiency purposes.
In particular, ATM Q.2931 signaling software, which is usually
complex, may be shared.  In this case, as will be shown, it is not
required to implement all layers of the ATM protocol between the
switch and end-point sides of the ATM UNI.  This decreases the
overall computational workload and allows the reuse of many software
components that may have to be developed and executed separately.

      This solution, termed SAAL routing, remaps service access point
identifiers to reuse ATM signaling software in environments where ATM
signaling for some or all virtual connections passing through an ATM
switch terminate within the switch itself.  This solution applies to
termination agents that must receive Q.2931 signaling; receiving user
data is optional.  The specific environments where this solution is
applicable are as follows:
  o  Mixed physical and virtual ports:  In this configuration, the
ATM
      signaling software supports both physical lines and embedded
ATM
      termination agents.
  o  Virtual ports only: In this configuration, the...