Juniper Networks, Inc.

Szelap Philip Chang

Manoj Apte

Saravanan Deenadayalan

A network device comprises a service card (e.g., a dynamic flow capture (DFC) service card) executing a communication protocol to receive, from one or more control sources, flow capture information specifying at least one destination and criteria for matching one or more packet flows. The network device includes a network interface card to receive a packet from a network, a packet replication module to replicate the packet, and a control unit to provide the replicated packet from the interface card to the DFC service card. The network device includes a filter cache that caches flow capture information recently received from the control sources. The network device may provide real-time intercept and relaying of specified network-based communications. Moreover, the techniques described herein allow control sources to tap packet flows with little delay after specifying flow capture information, e.g., within 50 milliseconds, even under high-volume networks.

Network device having service card for dynamic flow capture and monitoring of packet flows

Techniques are described for managing timeouts of filter criteria in a packet flow capture applications. The techniques allow for handling large amounts of timeouts used when monitoring a high volume of packet flows, without placing extreme demands on the operating system for managing the timeouts. The timeout data structure may be a circular array having a plurality of elements. The timeout array represents a span of time and the elements represent sequential units of time. Each element contains one or more pointers. The pointer may point to an entry in the filter table, or may be a null pointer. A timer thread periodically checks the timeout array to determine whether any timeouts occur at the current time. The timer thread checks the element of the array corresponding to the current time by computing an index into the array based on the current time.

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San Jose, CA, United States of America

Szelap Philip Chang