Browse Prior Art Database

Integrated-Services Digital Network Bearer Service Selection in an Asynchronous Transfer Mode Network

IP.com Disclosure Number: IPCOM000119123D
Original Publication Date: 1997-Dec-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 4 page(s) / 97K

Publishing Venue

IBM

Related People

Lancon, E: AUTHOR [+4]

Abstract

The Asynchronous Transfer Mode (ATM) technology provides a single transmission and switching infrastructure capable to offer both services of traditional circuit switch networks and packet switch networks. In particular, ATM allows the merging of voice and data on a single network.

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

Integrated-Services Digital Network Bearer Service Selection in an
Asynchronous Transfer Mode Network

      The Asynchronous Transfer Mode (ATM) technology provides a
single transmission and switching infrastructure capable to offer
both services of traditional circuit switch networks and packet
switch networks.  In particular, ATM allows the merging of voice and
data on a single network.

      For an interim period of time, the equipment needs to provide
migration solutions:  this bulletin describes an Interworking
Facility (IWF) between Integrated-Services Digital Network (ISDN) and
ATM (IWF).  It focuses on the way to select call-by-call the type of
ATM service that better fits to the requested ISDN service.

      An ISDN to ATM IWF can also provide additional services, such
as voice compression, modem demodulation, etc.  It is also possible
to select call-by-call these complementary services.

      Most Time Division Multiplexing (TDM) switches (PABX or CX)
providing ISDN interfaces can only switch 64 kbps circuits.  This
limitation is acceptable when most of the traffic is made of Pulse
Code Modulation (PCM) voice communications that use exactly 64 kbps
each.  With technology progresses (ATM, voice compression), it is
possible to better optimize network resources:
  o  The voice communications can be compressed and transported
      on a fraction of 64 kbps.
  o  The data traffic can be transported using either AAL1 circuit
      emulation or AAL5 if it is structured in High-Level Data Link
      Control (HDLC) frames.
  o  The voice and data traffic can be merged efficiently.
  o  The different ISDN channels can be supported:  B, H0, H11.

      The problem is to interconnect TDM or ISDN equipment through an
ATM network and optimize dynamically (call by call) the type of ATM
connection which is mapped on each ISDN call setup.  It is also
interesting to differentiate the type of service provided according
to the destination of the call.  For instance, a voice call can be
transported transparently for short distance calls or can be
compressed for overseas calls because telecommunication costs are
more expensive.

      There is not enough information in the ISDN call setup to
derive directly the best features of the connection and the ATM
Quality...