Telephonic communications – Plural exchange network or interconnection – With interexchange network routing
Reexamination Certificate
1997-12-15
2001-11-06
Hong, Harry S. (Department: 2642)
Telephonic communications
Plural exchange network or interconnection
With interexchange network routing
C370S397000, C370S408000, C370S409000, C370S410000, C370S905000, C379S229000
Reexamination Certificate
active
06314174
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to an apparatus for and a method of controlling calls, and a storage medium which stores a call control program, and more particularly to a call control apparatus for releasing a call, a call control apparatus for establishing a call, a call control method of releasing a call, a call control method of establishing a call, a storage medium which stores a call control program for releasing a call with a computer, and a storage medium which stores a call control program for establishing a call with a computer.
(2) Description of the Related Art
As the networking technology advances, needs for information communications increase, and services for providing such information communications are available in a diverse range. One service that is applicable to the NVOD (Near-Video-On-Demand) system employs a multicast call control function.
According to the multicast call control function, information such as sound and image information sent from a transmission terminal is copied in a switching exchange, and distributed to a plurality of reception terminals according to a point-to-multipoint multicast routing process.
A switching exchange with a multicast call control function establishes and releases calls between terminals and adjacent switching exchanges according to a user-network interface (UNI) or a network-network interface (NNI) which has been standardized by ITU-T.
A switching exchange with a multicast call control function copies information at a suitable branching point and sends the information to a plurality of users according to a point-to-multipoint multicast routing process.
FIG. 20
of the accompanying drawings shows in block form a connected configuration of a multicast call control system. In the multicast call control system, a transmission terminal for transmitting information is referred to as a root, and a reception terminal for receiving information is referred to as a leaf, with a switching exchange corresponding to a node.
In
FIG. 20
, a node N
1
is connected to a root R
1
and nodes N
2
, N
3
, N
4
are connected to the node N
1
. Leaves L
1
, L
2
are connected to the node N
2
. Leaves L
3
, L
4
are connected to the node N
3
. Leaves L
5
, L
6
are connected to the node N
4
.
Information transmitted from the root R
1
is copied in each of the nodes N
1
-N
4
, and multicast to the leaves L
1
-L
6
.
To release the leaves L
1
-L
6
, an REL signal which represents a release request massage is issued from the root R
1
for thereby releasing all the leaves L
1
-L
6
which belong to the same call.
FIG. 21
of the accompanying drawings illustrates a releasing sequence for releasing the leaves L
1
-L
6
of the multicast call control system shown in FIG.
20
.
The releasing sequence shown in
FIG. 21
is carried out as follows:
[S
1
] The root R
1
transmits an REL signal which represents a release request massage to the node N
1
.
[S
2
] The node N
1
transmits an RLC signal which is a response signal to the root R
1
.
[S
3
] The node N
1
transmits the REL signal successively to the nodes N
2
, N
3
, N
4
.
[S
4
] The nodes N
2
, N
3
, N
4
transmit respective RLC signals to the node N
1
.
The above releasing process is prescribed according to ITU-T recommendations Q.2971, Q2722.1. These ITU-T recommendations, however, fail to refer to the order in which a plurality of output paths issue respective release request messages. While the node N
1
issues REL signals successively to the nodes N
2
, N
3
, N
4
in the order named in
FIG. 21
, the node N
1
does not need to issue REL signals in the illustrated order, but may issue REL signals in an arbitrary order.
The above releasing process does not take into account any efficient release order. Therefore, depending on the order of issuance of release request messages, a delay time spent after a root sends a release request to a network until a final leaf is released may become very long.
Another problem is that when a new multicast call is to be established after a root has issued a release request message to a network, if simultaneous releasing of a previously established multicast call is still uncompleted in the network, then designated terminals may possibly remain busy, and a new call may not be established to those designated terminals.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a call control apparatus for effecting a call releasing process efficiently by shortening a call release delay time.
Another object of the present invention is to provide a call control apparatus for effecting a call establishing process efficiently by shortening a call release delay time.
Still another object of the present invention is to provide a call control method of effecting a call releasing process efficiently by shortening a call release delay time.
Yet still another object of the present invention is to provide a call control method of effecting a call establishing process efficiently by shortening a call release delay time.
A further object of the present invention is to provide a storage medium which stores a call control program for effecting a call releasing process efficiently by shortening a call release delay time.
A still further object of the present invention is to provide a storage medium which stores a call control program for effecting a call establishing process efficiently by shortening a call release delay time.
According to an aspect of the present invention, there is provided a call control apparatus for effecting a call releasing process, comprising delay time determining factor managing means for managing a delay time determining factor which determines a delay time of the call releasing process for each path, path order establishing means for establishing an order of paths having successively smaller delay times based on the delay time determining factor, and release request message transmitting means for transmitting release request messages to effect the call releasing process to nodes or terminals according to the order of paths.
According to another aspect of the present invention, there is provided a call control apparatus for effecting a call establishing process, comprising delay time determining factor managing means for managing a delay time determining factor which determines a delay time of the call establishing process for each path, path order establishing means for establishing an order of paths having successively smaller delay times based on the delay time determining factor, and establishment request message transmitting means for transmitting establishment request messages to effect the call establishing process to nodes or terminals according to the order of paths.
According to still another aspect of the present invention, there is provided a call control method of effecting a call releasing process, comprising the steps of managing a delay time determining factor which determines a delay time of the call releasing process for each path, establishing an order of paths having successively smaller delay times based on the delay time determining factor, and transmitting release request messages to effect the call releasing process to nodes or terminals according to the order of paths.
According to yet still another aspect of the present invention, there is provided a call control method of effecting a call establishing process, comprising the steps of managing a delay time determining factor which determines a delay time of the call establishing process for each path, establishing an order of paths having successively smaller delay times based on the delay time determining factor, and transmitting establishment request messages to effect the call establishing process to nodes or terminals according to the order of paths.
According to a further aspect of the present invention, there is provided a storage medium which stores a call control program for effecting a call releasing process by controlling a computer to function as delay time d
Fujitsu Limited
Hong Harry S.
Rosenman & Colin LLP
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