D-Link DWS-4026 Product Manual - Page 123

Software User Manual 12/10/09 D-Link Unified Access System Figure 62: sFlow Poller Configuration Table 52: sFlow Poller Configuration Field Description Slot/Port Receiver Index Poller Interval The sFlow Sampler Datasource for this flow sampler. This Agent will support Physical ports only. The sFlowReceiver for this sFlow Counter Poller. If set to zero, the poller configuration is set to the default and the poller is deleted. Only active receivers can be set. If a receiver expires, then all pollers associated with the receiver will also expire. The allowed range is 1 to 8. The maximum number of seconds between successive samples of the counters associated with this data source • Click Refresh to refresh the page with the most current data from the switch. SFLOW SAMPLER CONFIGURATION The sFlow Agent collects a statistical packet-based sampling of the switched flows and sends them to the configured receivers. A data source configured to collect flow samples is called a sampler. Packet Flow Sampling The Packet Flow Sampling mechanism carried out by each sFlow instance ensures that any packet observed at a Data Source has an equal chance of being sampled, irrespective of the Packet Flow(s) to which it belongs. Packet Flow Sampling is accomplished as follows: • When a packet arrives on an interface, the Network Device makes a filtering decision to determine whether the packet should be dropped. • If the packet is not filtered (dropped), a destination interface is assigned by the switching/routing function. • At this point, a decision is made on whether or not to sample the packet. The mechanism involves a counter that is decremented with each packet. When the counter reaches zero, a sample is taken. When a sample is taken, the counter that indicates how many packets to skip before taking the next sample is reset. The value of the counter is set to a random integer where the sequence of random integers used over time is the Sampling Rate. To access the sFlow Sampler Configuration page, click LAN > Administration > sFlow > Sampler Configuration in the navigation tree. Document 34CSFP6XXUWS-SWUM100-D7 Configuring sFlow Page 123