摘要:
Apparatus and method for implementing virtual path aggregation (VPA) of underlying virtual connections at a switching node of a connection based communications network. A multi-service traffic shaping module (MTSM) at the switch implements algorithms to aggregate the VC and VP connections onto the aggregate VP by representing an aggregate VP as a plurality of circular linked lists or loops and assigning each VC connection to a link or element in the circular linked lists according to traffic descriptors. Weighting factors are used as between loops to dynamically select the next loop to service. Once this loop is chosen, the next VC to be serviced is identified by examining the circular linked list structure.
摘要:
A method and apparatus for buffering data units in a communication switch that allows for configurable monitoring of the buffer contents is presented. Such an apparatus includes a context table that stores a plurality of independent group identifiers for each connection. Although the group identifiers may include a partition group identifier and a loss group identifier that is dependent on the partition group identifier, additional group identifiers are included in the context table for each connection that are independent of other group identifiers in the context table. Such a context table may be dynamically reconfigured in order to group connections for buffer monitoring operations related to congestion detection, traffic shaping, and data admission with respect to buffering. When a data unit is received corresponding to a particular connection, the context table is referenced to retrieve the set of group identifiers corresponding to that connection. As a cell is stored in the buffer, count values corresponding to at least some of the group identifiers included in the set of group identifiers for that connection are incremented. Similarly, when data is dequeued from the buffer for forwarding, the set of group identifiers for that particular data unit is determined and the counters corresponding to at least some of those groups are decremented. As such, the count value corresponding to each of the groups can be referenced to determine the number of data units corresponding to that group that are currently stored within the buffer.
摘要:
A method and apparatus for buffering data units in a communication switch that allows for configurable monitoring of the buffer contents is presented. Such an apparatus includes a context table that stores a plurality of independent group identifiers for each connection. Although the group identifiers may include a partition group identifier and a loss group identifier that is dependent on the partition group identifier, additional group identifiers are included in the context table for each connection that are independent of other group identifiers in the context table. Such a context table may be dynamically reconfigured in order to group connections for buffer monitoring operations related to congestion detection, traffic shaping, and data admission with respect to buffering. When a data unit is received corresponding to a particular connection, the context table is referenced to retrieve the set of group identifiers corresponding to that connection. As a cell is stored in the buffer, count values corresponding to at least some of the group identifiers included in the set of group identifiers for that connection are incremented. Similarly, when data is dequeued from the buffer for forwarding, the set of group identifiers for that particular data unit is determined and the counters corresponding to at least some of those groups are decremented. As such, the count value corresponding to each of the groups can be referenced to determine the number of data units corresponding to that group that are currently stored within the buffer.
摘要:
A method and apparatus for buffering data units in a communication switch that allows for configurable monitoring of the buffer contents is presented. Such an apparatus includes a context table that stores a plurality of independent group identifiers for each connection. Although the group identifiers may include a partition group identifier and a loss group identifier that is dependent on the partition group identifier, additional group identifiers are included in the context table for each connection that are independent of other group identifiers in the context table. Such a context table may be dynamically reconfigured in order to group connections for buffer monitoring operations related to congestion detection, traffic shaping, and data admission with respect to buffering. When a data unit is received corresponding to a particular connection, the context table is referenced to retrieve the set of group identifiers corresponding to that connection. As a cell is stored in the buffer, count values corresponding to at least some of the group identifiers included in the set of group identifiers for that connection are incremented. Similarly, when data is dequeued from the buffer for forwarding, the set of group identifiers for that particular data unit is determined and the counters corresponding to at least some of those groups are decremented. As such, the count value corresponding to each of the groups can be referenced to determine the number of data units corresponding to that group that are currently stored within the buffer.
摘要:
A method for incorporating a queuing device as a lossless processing stage in a network device in a communications network, comprising: monitoring a depth of a queue in the queuing device, the queue for receiving packets from an upstream device within the network device, the queuing device acting as a discard point by discarding packets when the queue is full; and, if the depth passes a predetermined threshold, sending a message to the upstream device to reduce a rate at which packets are sent to the queuing device to prevent the queue from filling and thereby preventing packet discarding and loss by the queuing device.
摘要:
The packet rate limiting method and system is used for detecting and blocking the effects of DoS attacks on IP networks. The method uses an ACL counter that stores an action parameter in the first 3 most significant bits and uses 13 bits as a packet counter. A rate limit is enforced by setting the packet counter to an initial value, and resetting this value at given intervals of time. The action parameter enables the ACL to accept or deny packets based on this rate limit. If the number of packets in the incoming flow saturates the packet counter before the reset time, the packets are denied access to the network until the counter is next reset. The denied packets may be just discarded or may be extracted for further examination.
摘要:
A method for verifying the integrity of data payloads of ATM cells passing through a switching device involves computing a payload integrity verification code for the payload portion of an ATM cell. The payload integrity verification code may be generated according to any error detection or error correction scheme. Preferably, the payload integrity verification code is stored in a portion of the standard ATM cell header which is not used while the cell is passing through the switching device. Preferably the payload integrity verification code is stored in all, or a portion of, the virtual path identifier or virtual connection identifier fields. The invention allows for the immediate identification of cells having corrupted payload data. Different actions may be taken on the detection of errors in the ATM cell header and ATM cell payloads respectively.
摘要:
A method for incorporating a queuing device as a lossless processing stage in a network device in a communications network, comprising: monitoring a depth of a queue in the queuing device, the queue for receiving packets from an upstream device within the network device, the queuing device acting as a discard point by discarding packets when the queue is full; and, if the depth passes a predetermined threshold, sending a message to the upstream device to reduce a rate at which packets are sent to the queuing device to prevent the queue from filling and thereby preventing packet discarding and loss by the queuing device.
摘要:
The packet rate limiting method and system is used for detecting and blocking the effects of DoS attacks on IP networks. The method uses an ACL counter that stores an action parameter in the first 3 most significant bits and uses 13 bits as a packet counter. A rate limit is enforced by setting the packet counter to an initial value, and resetting this value at given intervals of time. The action parameter enables the ACL to accept or deny packets based on this rate limit. If the number of packets in the incoming flow saturates the packet counter before the reset time, the packets are denied access to the network until the counter is next reset. The denied packets may be just discarded or may be extracted for further examination.
摘要:
A method and apparatus are provided for maintaining access control lists (ACLs) within TCAM on a line card in a data packet router, the rules being applied to incoming data packets. Each interface may be associated with multiple ACLs, and multiple interfaces may be associated with single shared ACLs. The shared ACLs include rules applicable to more than one interface. Other ACLs are specific to a particular interface. When searching for a rule to apply to an incoming data packet, the filter searches both the specific ACL and the shared ACLs associated with the interface over which the data packet arrived. Using the shared ACLs, duplication of common rules is reduced, thereby reducing the total number of rules stored on the line card and saving memory storage space. The invention is also applicable to sets of rules other than ACLs.