US 7,126,911 B2Granted

Timer rollover handling mechanism for traffic policing

AssigneeIntegrated Device Technology, Inc.

InventorsYongdong Zhao, Craig A. Lindahl

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Abstract

A network device may perform traffic policing to determine if incoming data cells are in conformance with policing parameters, including a theoretical arrival time (TAT), for each cell's communication channel. Each cell may have an arrival time according to a timer value. The timer value and TAT may rollover upon reaching a maximum value. The network device may be configured to account for such rollovers when determining cell conformance. For each communication channel, a table entry may include the policing parameters and rollover data. Each entry may also include operations and maintenance (OAM) data. The rollover data indicates the rollover phase relationship between the timer value and TAT parameter for each channel. The rollover data may be updated each rollover phase of the timer, for example as part of an OAM table scan process. The network device may be an Asynchronous Transfer Mode (ATM) traffic policing device or switch.

Claims32

Dependent claims

A network device, comprising:

a cell processing unit configured to receive incoming data cells from a network for a plurality of communication channels;
a timer configured to provide a timer value to said cell processing unit;
and
a memory coupled to said cell processing unit and configured to store one or more policing parameters and rollover data for each of the communication channels, wherein the rollover data comprises an indication of a rollover relationship between the timer value and one of the policing parameters for each of the communication channels;
wherein for each received incoming data cell, said cell processing unit is configured to assign an arrival time from the timer value and compare the received incoming data cell's arrival time to the one or more policing parameters for the received incoming data cell's communication channel to determine if the received incoming data cell is conforming or non-conforming to a rate for the communication channel, wherein said cell processing unit is configured to access the rollover data for the received incoming data cell's communication channel to account for the rollover relationship when comparing the arrival time to the one or more policing parameters;
and
wherein said memory is further configured to store operations and maintenance data indicating connection availability information for each communication channel.

4 more elements

A method, comprising:

receiving incoming data cells from a network for a plurality of communication channels, wherein each received incoming data cell has an arrival time from a timer value;
for each received incoming data cell, accessing one or more policing parameters and rollover data for the communication channel on which the incoming data cell was received, wherein the rollover data comprises an indication of a rollover relationship between the timer value and one of the policing parameters for each of the communication channels;
for each received incoming data cell, comparing the received incoming data cell's arrival time to the one or more policing parameters for the received incoming data cell's communication channel to determine if the received incoming data cell is conforming or non-conforming to a rate for the communication channel, wherein said comparing comprises using the rollover data for the received incoming data cell's communication channel to account for the rollover relationship between the arrival time and the one or more policing;
and
storing operations and maintenance data indicating connection availability information for each of the plurality of communication channels.

2 more elements

Dependencies are inferred from the claim text.