a) setting up at least one switched virtual circuit connec- The apparatus and the methods in accordance with the tion (SVC) between a first and second ingress/egress invention provide a mechanism for rapidly establishing point in the ATM network; communications connections through an ATM network
b) caching the at least one SVC for use by either the first while ensuring that the resources of the ATM network are or second ingress/egress points when a request for a 5 efficiently utilized. In accordance with the method, SVCs are communications connection through the ATM network set up between a first and second ingress/egress point in the is received by one of the ingress/egress points; ATM network and the SVCs are cached for later use by the
c) selecting an appropriate one of the at least one cached network 50 that network resources are not required for SVC SVCs when the request for a communications connec- setuP' Thls ensures that real-time services can be switched tion through the ATM network is received by one of the 10 througn the ATM network wlth a minimum of delay. It also ingress/egress points, if an appropriate cached SVC is ensures that network resources are efficiently used since available- and signaling overhead is minimized.
• ., i j o-w/-. * -ji * i i- i *i In accordance with a preferred embodiment of the
d) using the cached SVC to rapidly establish the commu- if , . ,, ^ ...
.~- .i i »r„», , , invention, the cache of SVCs is managed by software which
mcations connection through the AlM network. '„ , ,, ° o-.^
„ , r r ... 15 monitors SVC usage and adds SVCs to, or removes SVCs
1 tie invention is practised using an apparatus tor rapidly £ , , , r . , .,.
r . ^. ~ , from, the cache as demand tor service by a specific apph
estabhshing a communications connection through an asyn- ^. . , T ,
, * r i , • • . cation increases or decreases. In accordance with the pre
chronous transfer mode (AIM) network, comprising at least r , ... ^ r if ^. ,
,. j4 r J * * terred embodiment of the invention, SVCs are established
one machine programmed to perform the functions of: , . ^ . , . . . , ' , ^ . . . ,
and maintained in accordance with the characteristics of the
a) a switched virtual circuit connection (SVC) control 2Q seryice offered by the communications application. The agent which is responsible for SVC setup and release at syc caches are therefore preferably maintained by service an ingress/egress point for the ATM network; characteristic as well as by application.
b) an SVC caching manager that maintains an SVC cache in order to further speed up SVC setup, cross-connections table in which a record of each cached SVC is stored; (xCs) can also be cached in ATM network nodes. The same an(3 25 control objects and algorithms may be used for SVC and XC
c) an SVC selector that processes operation requests from caching. When XCs are cached, new SVCs can be set up a communications application which seeks to establish through the ATM network with minimal delay, thus further an SVC through the ATM network, or release an SVC reducing call setup time.
that is no longer required, the SVC selector selecting an Since the use of caching is parameter-driven, a commu
available cached SVC from the SVC cache table or 30 nications application is not obligated to use SVC caching.
requesting the SVC control agent to establish a new This enables flexible use of the apparatus in accordance with
SVC through the network when a process operation the invention and permits network managers to manage the
request is received from the communications applica- network in accordance with their needs and/or management
In accordance with a further aspect of the invention there 35
is provided a method of rapidly establishing a cross- BRIEF DESCRIPTION OF THE DRAWINGS
connection through an asynchronous transfer mode (ATM) T,, • .. .,, , c , . , , c
., . . , J . v / Ihe invention will now be further explained by way of
switch, comprising the steps of: , , , ... c , c' „ ■ , ■
r to r example only and with reference to the following drawings
a) setting up at least one cross-connection (XC) between m w[jic[j
an ingress port and an egress port in the ATM switch; 40 . .
FIG. 1 is a schematic diagram of a prior art ingress/egress
b) caching the at least one XC for use by the ingress port node in an ATM networ]j.
when a request for a cross-connection through the ATM „ . , , , ,. ' , . , . . ,
FIG. 2 is a block diagram showing the principal compo
switch is received*
.' nents of the apparatus for SVC caching in accordance with
c) selecting a one of the at least one cached XCs when the ^ invention'
request for a cross-connection through the ATM switch 45 . .
is received' and 3 is a schematic diagram of a call setup and call
,' , _ ... .... , release message flow using the methods and apparatus in
d) using the selected XC to rapidly establish the cross- , f, . f. . , . , / , 0,,^ •
'b . , , , „TM, • i accordance with the invention, in which a cached SVC is
connection through the AIM switch. , c , . , . , c. „ ,
rTn.r, .. .,. used tor the call and returned to the cache after call release; 1ms further aspect of the invention is practised using
apparatus for rapidly establishing a cross-connection 50 FIG' 4 15 a schematic diagram of a call setup and call
through an asynchronous transfer mode (ATM) switch, release message flow using the methods and apparatus in
comprising an ATM switch control element programmed to accordance with the invention, in which a cached SVC is perform the functions of:
a) a cross-connect (XC) control agent which is respon- „ sible for XC set up and release in the ATM switch; FIG- 5 is a schematic diagram showing two examples of
, x , • , • , • , • a message flow using the apparatus in accordance with the
b) a cross-connect caching manager which maintains an . . T & „ , ,r„., vr^ u t ui • u- u A t u u Avr^- invention to route Internet Protocol messages over AlM; XC cache table in which a record of each cached XC is &'
stored' and FIG. 6 is a schematic diagram of a cached cross
c) a cross-connect selector which processes operation 60 connection in an ATM switch; and
requests that seek to establish an XC through the ATM FIG. 7 is a schematic diagram of an XC caching system switch, or release an XC that is no longer required, the in accordance with the invention, cross-connect selector selecting an available cached XC from the XC cache table or requesting the crossconnect control agent to establish a new XC through 65 the switch when a process operation request is FIG. 1 shows one prior art arrangement for an ingress/ received. egress point, generally indicated by the reference 10, in an