WESM zl Management and Configuration Guide WT.01.28 and greater

13-4
sFlow Agent
Overview
The sFlow agent obtains the counters by periodically polling radios. The agent polls
radios as needed to fill datagrams most efficiently. However, you can configure the
maximum time that can elapse before a radio must be polled.
sFlow Receiver
The sFlow receiver, which receives samples from agents all over the network,
combines and analyzes the samples to produce a picture of network activity. This
picture can be quite detailed. For example, the sFlow receiver can determine not only
how much traffic the Wireless Edge Services zl Module’s RP radios are handling,
but also which devices are contributing to that traffic—and which are contributing
most.
Capabilities vary among sFlow receivers; some uses for sFlow include:
■ establishing a baseline picture of network activity against which later activity
can be compared and analyzed for signs of security breaches
■ monitoring congestion and other Quality of Service (QoS) issues
■ auditing and billing for network usage
■ finding and diagnosing network problems
An sFlow receiver can effectively monitor a large network because sFlow’s sampling
techniques extract only the necessary data from the traffic streams on each data
source, consuming minimal device and network resources in the process. This
approach shifts the burden of data manipulation and analysis from the sFlow agent
to the sFlow receiver. In addition, the receiver can generate an accurate picture of
network traffic even when agents sample a relatively small percentage of traffic.
An example of an sFlow receiver is ProCurve Manager Plus (PCM Plus).
Configuring sFlow Receiver Instances
As described above, an sFlow agent forwards datagrams to an sFlow receiver. Each
relationship between an agent and a receiver is called a receiver instance. Often the
receiver uses the SNMP protocol to contact the agent, reserve a receiver instance, a
configure sFlow. Alternatively, receiver instances can be set up on the agent itself.
The Wireless Edge Services zl Module can accommodate up to six sFlow receivers.
The module’s receiver instances can be configured in one of three ways:
1. The sFlow receiver contacts the module’s agent and uses SNMP to reserve and
configure a receiver instance (only instances 4, 5, and 6).