Multiplex communications – Diagnostic testing – Of a switching system
Reexamination Certificate
1999-03-29
2003-07-15
Vincent, David (Department: 2661)
Multiplex communications
Diagnostic testing
Of a switching system
C370S253000
Reexamination Certificate
active
06594237
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to a fixed length data processing apparatus, in particular, to a fixed length data processing apparatus suitable for use to execute operation, administration and maintenance (OAM) of ATM (Asynchronous Transfer Mode) communication using fixed length data of 53 bytes called an ATM cell.
(2) Description of Related Art ATM technique is.being introduced for the purpose of realization of B-ISDN (Broadband aspect of ISDN) communication network so as to comply with high speed (large capacity) communications, variable bit rate communications for image, communication systems having various connection configurations such as point-to-point, point-to-n points (n is 2 or more), n points-to-n points, and the like, required presently.
For instance, in SDH (Synchronous Digital Hierarchy) transmission network [called SONET (Synchronous Optical Network) in the North America], it is tried to map (store) signals for various communication services as ATM cells (fixed length data for asynchronous communication) onto a portion of payload of an SDH transmission frame [called STM (Synchronous Transfer Module), or STS (Synchronous Transport Signal) in SONET] and transmit the signal.
When an ATM cell is mapped onto the SDH transmission frame (hereinafter simply referred as a transmission frame, occasionally), a demand is to identify the ATM cell mapped onto the transmission frame in units of ATM cells and perform operation, administration and maintenance [a data (cell) processing such as a terminating processing on an OAM cell] at a level of ATM communication even in the SDH transmission network.
In a ring network
1
′ configuring the SDH transmission network shown in
FIG. 55
, for example, it is necessary to interpose an ATM processing apparatus
4
′ for performing the above cell processing between SDH transmitting apparatus
2
′ and
3
′.
Each of the SDH transmitting apparatus
2
′ and
3
′ has a function of mapping an ATM cell on or taking out (demapping) an ATM cell from a transmission frame. Since the ring network
1
′ (SDH transmitting apparatus
2
′ and
3
′) accommodates a plurality of SDH transmitting apparatus
9
′-
1
through
9
′-n (n is an integer not less than 2) which are transmission points in the lower hierarchy, as shown in
FIG. 55
, the ATM processing apparatus
4
′ is required to perform the above cell processing on each transmission point. In concrete, it is necessary to separately perform the above cell processing on each transmission frame in a lower layer handled in each of the SDH transmission apparatus
9
′-
1
through
9
′-n [distinguished as an STS channel #i (i=1 through n) in each of the SDH transmitting apparatus
2
′ and
3
′ (in a transmission frame in a higher layer)].
For this, each of the SDH transmitting apparatus
2
′ and
3
′ has mapping/demapping (MAP/DEMAP) units
2
′-
1
through
2
′-n and
3
′-
1
through
3
′-n according to the number of STS channels #i as shown in
FIG. 56
, for example. Each of the mapping/demapping units
2
′-
1
through
2
′-n and
3
′-
1
through
3
′-n includes a demapping unit
2
′
d
or
3
′
d
for taking out an ATM cell from a transmission frame in the upstream or in the downstream and outputting the ATM cell to the ATM cell processing unit
4
′-i and a mapping unit
2
′
m
or
3
′
m
for storing (mapping) an ATM cell from the ATM cell processing unit
4
′-i in a transmission frame in the upstream or in the downstream and outputting the ATM cell to another transmitting apparatus. The ATM processing apparatus
4
′ has ATM cell processing units
4
′-
1
through
4
′-n according to the number of the STS channels #i.
Each of the SDH transmitting apparatus
2
′ and
3
′ can thereby perform the above ATM cell mapping/demapping process for each STS channel #i by the mapping/demapping units
2
′-
1
through
2
′-n and
3
′-
1
through
3
′-n. The ATM cell processing unit
4
′-i can perform the above cell processing for each STS channel
Namely, the ATM processing apparatus
4
′performs the cell processing on ATM cells in transmission frames handled by each of the SDH transmitting apparatus
9
′-
1
through
9
′-n separately for each STS channel #i by each exclusive ATM cell processing unit
4
′-i serially.
For instance, an ATM cell from the SDH transmitting apparatus
9
′
1
,
9
′-
2
, . . . or
9
′-n in the lower hierarchy of the SDH transmitting apparatus
3
′ is taken out from a transmission frame in the mapping/demapping unit
3
′-
1
,
3
′-
2
, . . . or
3
′-n corresponding to, the STS channel #i, and sent to a corresponding ATM cell processing unit
4
′-i according to an internal reference cell cycle of the ATM processing apparatus
4
′.
Each of the ATM cell undergoes the cell processing in the ATM cell processing unit
4
′-i corresponding to the STS channel #i, is mapped on a transmission frame in the corresponding mapping unit
2
′-
1
,
2
′-
2
, . . . or
2
′-n, and transmitted to the SDH transmitting apparatus
9
′-
1
,
9
′-
2
, . . . or
9
′-n accommodated in the lower hierarchy of the SDH transmitting apparatus
2
′.
Each of the ATM cell processing units
4
′-i identifies an ATM cell, and executes fault management [termination of an AIS (Alarm Indication Signal) or an RDI (Remote Defect Indication) cell] on an ALM (Alarm) cell of an OAM cell, mainly.
For instance, when the ATM processing apparatus
4
′ receives an OAM (ALM) cell (VP/VC-AIS) indicating occurrence of a trouble within a certain VP/VC connection, the ATM processing apparatus
4
′ notifies of a similar AIS the downstream, or when receiving an alarm (SONET alarm or the like) in a higher layer than AIS, the ATM processing apparatus
4
′ generates a VP/VC-AIS/RDI cell and sends the cell to a desired destination.
For this, each of the ATM cell processing unit
4
′-i has, as shown in
FIG. 56
, for example, a cell identifying unit
4
′
a
, a cell generating unit
4
′
b
, a cell inserting unit
4
′
c
for downstream, a cell inserting unit
4
′
d
for upstream, and a microcomputer I/F unit
4
′
e.
The cell generating unit
4
′
b
generates an ALM cell (VP-AIS, VC-AIS), and sends the cell to the downstream through the DnS cell inserting unit
4
′
c
. On the other hand, an ALM cell (VP-RDI, VC-RDI) to be sent back is sent to the upstream through the UpS cell inserting unit
4
′
d.
The microcomputer I/F unit
4
′
e
has an interface used to set an operation channel, operation environments and the like from a system CPU or collect maintenance and management information (ALM information and the like).
The ALM cell or the like outputted from the ATM cell processing unit
4
′-
1
,
4
′-
2
, . . . , or
4
′-n is again mapped on a transmission frame in the mapping/demapping unit
2
′-
1
,
2
′-
2
, . . . or
2
′-n, and received by another apparatus which is a destination of the ALM cell.
When data (ATM cell) such as images having a larger volume of information is transmitted by applying VOD (Video on Demand) to the above ring network
1
′, for example,a transmission capacity of the ring network
1
′ is increased. When a transmission rate of the ring network
1
′ is increased as above, a rate of occurrence of ATM cell loss, misinsertion and the like in the network (ATM communication) is increased with an increase of quantity of data (ATM cell) flow.
In particular, when a network structure (connection configuration) for a large capacity transmission of one point-to-n points or n points-to-n points, a variable
Kada Kazuhisa
Kiuchi Hidenori
Mochizuki Hideaki
Murakawa Hiroshi
Okura Ritsuko
Fujitsu Limited
Vincent David
LandOfFree
Fixed length data processing apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Fixed length data processing apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fixed length data processing apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3072520