ip flow-export enable

Flow export enables you to export network statistics to external collectors that provide information about network data flows such as the top users, peak usage times, traffic accounting, security, and traffic routing. You can export pre-optimization and post-optimization data to an external collector. The Top Talkers feature enables a report that details the hosts, applications, and host and application pairs that are either sending or receiving the most data on the network. Top Talkers does not use a NetFlow Collector.

SteelHeads support NetFlow v5.0, CascadeFlow, NetFlow v9, and CascadeFlow-compatible. For details on NetFlow, including Riverbed-specific record flow fields for v9, see the SteelHead Deployment Guide.

Flow export requires the following components:

• Exporter - When you enable flow export support, the SteelHead exports data about flows through the network.

• Analyzer - A collection of tools used to analyze the data and provide relevant data summaries and graphs. NetFlow analyzers are available for free or from commercial sources. Analyzers are often provided in conjunction with the collectors.

Before you enable flow export in your network, consider the following:

• Flow data typically consumes less than 1% of link bandwidth. Care should be taken on low bandwidth links to ensure that flow export does not consume too much bandwidth and thereby impact application performance.

• You can reduce the amount of bandwidth consumption by applying filters that only export the most critical information needed for your reports.

For virtual in-path deployments such as WCCP or PBR, because the traffic is arriving and leaving from the same WAN interface, when the SteelHead exports data to a flow export collector, all traffic has the WAN interface index. This is the correct behavior because the input interface is the same as the output interface.

Prior to Netflow v9, for virtual in-path deployments, because the traffic is arriving and leaving from the same WAN interface, when the SteelHead exports data to a NetFlow collector, all traffic has the WAN interface index. This is the correct behavior because the input interface is the same as the output interface. For Netflow v9, LAN and WAN interfaces are reported for optimized flows.