Multiplex communications – Pathfinding or routing – Switching a message which includes an address header
Reexamination Certificate
1998-09-10
2004-01-27
Hsu, Alpus H. (Department: 2665)
Multiplex communications
Pathfinding or routing
Switching a message which includes an address header
C370S409000, C370S522000
Reexamination Certificate
active
06683880
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to a switching system, a subscriber apparatus and a switching apparatus suitable for allowing a signaling channel for controlling setting of a virtual connection (for setup) between a switching apparatus and a subscriber apparatus to be redundant.
(2) Description of the Related Art
FIG. 19
is a block diagram showing an example of an ATM (Asynchronous Transfer Mode) switching system. The ATM switching system shown in
FIG. 19
includes an ATM switch
100
having interface apparatus (OC3cs: Optical Carrier 3 concatenated)
101
A through
101
C, middle-speed interface multiplexing apparatus (MIFSHS: Middle Interface Shelf)
102
A and
102
B, an ATM switch unit (CRSWSH: Cell Relay Switch Shelf)
103
, a central control apparatus (CC: Central Controller)
104
, a main storage apparatus (MM: Main Memory)
105
, a hard disk (Hard Disk Unit)
106
, signaling control apparatus (BSGCS: Broadband Signaling Controllers)
107
A and
107
B and inter-processor control apparatus (PACs: Processor Access Controllers)
108
, and a subscriber apparatus [line concentrator: HDT (Head-end Distribution Terminal)]
200
accommodating subscriber terminals (users) to provide VOD (Video On Demand) service and the like to the users.
Each of the above interface apparatus (OC3cs)
101
A through
101
C is an optical interface of a transmission capacity of about 155 Mb/s used in SONET (Synchronous Optical Network) conforming to SDH (Synchronous Digital Hierarchy) transmission system. If a transmission rate of video image in the above VOD service is 3.4 Mb/s using a desired moving picture compressing technique such as MPEG 2 or the like, each of the interface apparatus
101
A and
101
B can set a maximum of about 50 lines (channels) between the HDT
200
and itself.
Each of the middle-speed interface multiplexing apparatus (MIFSHS)
102
A and
102
B accommodates an appropriate number of interface apparatus of 155 Mb/s
101
A through
101
C, and multiplexes data (ATM cells) from each of the interface apparatus
101
A through
101
C in order to unify a data transmission rate to 2.4 Gb/s between the ATM switch unit
103
and itself.
The ATM switch unit
103
performs a self-routing process on the basis of tag information [an apparatus address, VPI (Virtual Path Identifier)/VCI (Virtual Channel Identifier) and the like to be described later] attached to a header of a received ATM cell to output the received cell to a relevant port.
The central control apparatus (CC)
104
collectively controls operations of the ATM switch
100
(call control such as setup, disconnecting and the like, accounting control, call history management, and the like). The central control apparatus (CC)
104
can suitably give necessary settings to the middle speed interface multiplexing apparatus (MIFSHS)
102
A and
102
B, and the ATM switch unit
103
through the above inter-processor control apparatus (PACs)
108
, and the signaling control apparatus (BSGCS)
107
A and
107
B.
The main storage apparatus (MM)
105
stores software required in the operations of the central control apparatus
104
along with various data such as subscriber data, accounting data, history data and the like. The hard disk
106
backups contents stored in the main storage apparatus
105
, or stores accounting data or history data of all subscribers that the main storage apparatus cannot manage.
In the switching system with the above structure, when a certain subscriber terminal (user) A requests for a communication with another subscriber terminal (user) B, for example, the request is transmitted to, for example, the interface apparatus
101
A as a SETUP signal of an ATM cell through the HDT
200
.
The interface apparatus
101
A refers to a correspondence table
111
as shown in
FIG. 20
managed by the interface apparatus
101
A with a virtual connection number [VPI (Virtual Path Identifier)/VCI (Virtual Channel Identifier)=0/5 of the SETUP signal] attached to the header of the received ATM cell as a key to obtain an apparatus address and a signaling channel number of an opposite signaling control apparatus
107
A.
The obtained apparatus address and signaling channel number are attached to the received ATM cell, and sent to the ATM switch unit
103
through the middle-speed interface multiplexing apparatus
102
A.
The ATM switch unit
103
allows self-routing of the received ATM cell on the basis of the apparatus address attached to the received ATM cell, and sends out the received ATM cell to the signaling control apparatus
107
A from a relevant port.
The signaling control apparatus
107
A converts the received ATM cell into a signaling message form, while giving a corresponding signaling channel number to the received SETUP signal by referring to a correspondence table
112
as shown in
FIG. 21
with the above apparatus address as a key and transmitting the SETUP signal to the central control apparatus
104
.
The central control apparatus
104
performs processes described in {circle around (1)} through {circle around (5)} below on the basis of information in the SETUP signal received from the signaling control apparatus
107
A.
{circle around (1)} referring to signaling channel management data
113
as shown in
FIG. 22
with the signaling channel number attached to the received SETUP signal as a key to call corresponding physical interface management data
114
, further determining a physical interface number (a number of the interface apparatus
101
A) and a VPI value that should be set as a virtual communication path for a source (HDT
200
) from VPCI (Virtual Path Connection Identifier) that is designated in the SETUP signal;
{circle around (2)} selecting an idle VCI in the determined VPI and determining it;
{circle around (3)} referring to subscriber number translation data
115
shown in
FIG. 22
with a destination number set in the SETUP signal as a key to call corresponding subscriber data
116
, obtaining a subscriber address of the destination;
{circle around (4)} calling the physical interface management data
114
corresponding (linked by a pointer) to the subscriber data
116
at the subscriber address, and determining a physical interface number (a number of the interface apparatus
101
B), a VPI value and a VCI value of a virtual communication path set for the destination subscriber; and
{circle around (5)} transmitting a SETUP signal, to which a signaling channel number is attached, to the signaling control apparatus
107
B accommodating a signaling channel of the destination.
The above data
113
through
116
are stored as data in a table form in the main storage apparatus
105
.
When receiving the SETUP signal from the central control apparatus
104
, the signaling control apparatus
107
B assembles the SETUP signal into an ATM cell, while referring to a correspondence table
112
similar to that shown in
FIG. 21
with the signaling channel number attached to the SETUP signal as a key to obtain an apparatus address of the opposite interface apparatus
101
C, assembling the apparatus address and attaching it to the ATM cell, and sending the ATM cell to the ATM switch unit
103
.
The ATM switch unit
103
transmits the received ATM cell to the interface apparatus
101
C on the basis of the apparatus address attached to the received ATM cell. The interface apparatus
101
C refers to a correspondence table
111
similar to that shown in
FIG. 20
with the apparatus address attached to the received ATM cell as a key to obtain a virtual connection number (VPI/VCI value), sets the number to the received ATM cell, and sends out the ATM cell as a SETUP signal to the destination.
After that, signaling messages such as confirmation (SETUP ACKNOWLEDGE) of the above SETUP signal and the like are exchanged among the source, the destination and the ATM switch
100
. The ATM switch
100
(central control apparatus
104
) sets (notifies) the apparatus address and VPI/VCI of the opposite apparatus to each of the interface apparat
Fujitsu Limited
Hsu Alpus H.
Katten Muchin Zavis & Rosenman
Tran Thien D
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