
		AT&T Laboratories Cambridge

Collapsed LAN

These pages were last modified 28/9/01.

Tripwire

Tripwire is a means whereby the data transfer mechanism (be it in-bound or out-bound) of an asynchronous network interface is snooped using hardware. This hardware is able to perform an application-defined action when some application-defined data transfer has occurred. Some examples of Tripwire actions are: enqueuing an event, or raising an interrupt and presenting a queue of identifiers indicating those processes which have had Tripwire matches.

We implement Tripwire by using a pipelined array (to achieve the required match cycle of 30ns) of three Content Addressable Memory (CAM) devices to monitor the local bus for addresses or address ranges, which have been marked as 'interesting'.

Please note that the techniques disclosed here have been the subject of patent applications