ATM processing apparatus

Details ATM processing apparatus ATM processing apparatus

1998-05-06

2001-08-28

Chin, Wellington (Department: 2664)

Multiplex communications

Pathfinding or routing

Switching a message which includes an address header

C370S395430, C370S351000

Reexamination Certificate

active

06282200

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to an ATM (Asynchronous Transfer Mode) apparatus coping with ATM cells; particularly relating to an apparatus which collects statistical information on user traffic.
Conventional ATM processing apparatus represented by a switching system have a function of collecting user traffic, and statistical information in the ATM layer's cell level. The function is performed by a line interface unit or an ATM switching unit or other related connections, which counts the number of passed-by cells and discarded cells, etc.
However, the following problems appear for the networks in which data communication networks, such as the Internet represented by the Internet Protocol Over ATM (IPOA) or Next Hop Resolution Protocol (NHRP), are constructed on the ATM networks. Specifically, no more than cell-level traffic information can be collected due to the fact that the ATM network has no capability to identify packets, even though actual traffic is made on the packet unit basis. Thus, no statistic information on packet-level traffic can be exactly collected.
Additionally, in the ATM network, the means for collecting packet-level statistical information requires an addition of a communication apparatus, such as the ATM router to the ATM network in order to terminate the ATM Adaptation Layer (AAL) and to rebuild a packet. This results in a large increase in cost and a deterioration of the data transmission throughput for a packet-level routing process in the ATM network.
SUMMARY OF THE INVENTION
Accordingly, the objective of the present invention is to provide an ATM processing apparatus for collecting packet-level traffic information at a low price, without introducing an additional apparatus such as an ATM router.
The ATM processing apparatus according to the present invention comprises an AAL statistical information collection unit which takes in cell flow between a physical line termination unit and an ATM cell processing unit, collecting AAL-level statistical information. The AAL statistical information collection unit comprises: a connection information table; which holds predetermined connection information, a cell check unit; which checks cell flow between the physical line termination unit and the ATM cell processing unit (by using the connection information to detect a cell including the ending part of a cell-based PDU [Protocol Data Unit] in an adaption layer), an information length detection unit; which detects the user information length from an information length field in an ending cell (when identified), a statistical information calculation unit; which calculates the information sent from both the cell check unit and the information length detection unit to modify the statistical information, and a statistical information table; which holds statistical information for each connection, accessed and modified by the statistical information calculation unit.
The cell check unit determines whether an input cell is of the AAL type and also whether it is an ending cell from the content of the connection information table, detecting the passage of one Protocol Data Unit (PDU). When an ending cell is then identified, the information length detection unit will know the payload length of the PDU, or user information length. To collect AAL-level, statistical information, the statistical information calculation unit can modify the statistical information table in accordance with both the Virtual Path Identifier (VPI)/Virtual Channel Identifier (VCI) values sent from the cell check unit, and the user information length sent from the information length detection unit.


REFERENCES:
patent: 5835710 (1998-11-01), Nagami et al.
patent: 5867677 (1999-02-01), Tsukamoto
patent: 6002692 (1999-12-01), Wills
patent: 5-37568 (1993-02-01), None
B-ISDN ATM Adaptation Layer (AAL) Type 5 Specification, (1996).

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