Supported Platforms
Traffic Sampling, Forwarding, and Monitoring Overview
Traffic sampling allows you to sample IP traffic based on particular input interfaces and various fields in the packet header. You can also use traffic sampling to monitor any combination of specific logical interfaces, specific protocols on one or more interfaces, a range of addresses on a logical interface, or individual IP addresses. Information about the sampled packets is saved to files on the router's hard disk.
The forwarding policies allow you to configure the per-flow load balancing, port mirroring, and Domain Name System (DNS) or Trivial File Transfer Protocol (TFTP) forwarding. In Junos OS Release 9.0 and later, you can configure per-prefix load balancing. This feature enables the router to elect the next hop independent of the route chosen by other routers. The result is a better utilization of available links.
Traffic sampling and forwarding are supported only on routers equipped with an Internet Processor II application-specific integrated circuit (ASIC). To determine whether a routing platform has an Internet Processor II ASIC, use the show chassis hardware command.
Traffic sampling is not meant to capture all packets received by a router. We do not recommend excessive sampling (a rate greater than 1/1000 packets), because it can increase the load on your processor. If you need to set a higher sampling rate to diagnose a particular problem or type of traffic received, we recommend that you revert to a lower sampling rate after you discover the problem or troublesome traffic.
