Dell Force10 S4820T FTOS Command Reference Guide - Page 1397

48 sFlow Overview sFlow commands are supported by FTOS on all Dell Force10 platforms as indicated by the characters that appear under each of the command headings: e E-Series, c C-Series, s S-Series, , or . FTOS sFlow monitoring system includes an sFlow Agent and an sFlow Collector. The sFlow Agent combines the flow samples and interface counters into sFlow datagrams and forwards them to the sFlow Collector. The sFlow Collector analyses the sFlow Datagrams received from the different devices and produces a network-wide view of traffic flows. Important Points to Remember • Dell Force10 recommends that the sFlow Collector be connected to the Dell Force10 chassis through a line card port rather than the RPM Management Ethernet port. • FTOS exports all sFlow packets to the sFlow Collector. A small sampling rate can equate to a large number of exported packets. A backoff mechanism will automatically be applied to reduce this amount. Some sampled packets may be dropped when the exported packet rate is high and the backoff mechanism is about to or is starting to take effect. The dropEvent counter, in the sFlow packet, will always be zero. • sFlow sampling is done on a per-port basis. • Community list and local preference fields are not filled up in the extended gateway element in the sFlow datagram. • The 802.1P source priority field is not filled up in the extended switch element in the sFlow datagram. • Only Destination and Destination Peer AS numbers are packed in the dst-as-path field in the extended gateway element. • If the packet being sampled is redirected using PBR (Policy-Based Routing), the sFlow datagram may contain incorrect extended gateway/router information. • sFlow does not support packing extended information for IPv6 packets. Only the first 128 bytes of the IPv6 packet is shipped in the datagram. • The source VLAN field in the extended switch element will not be packed in case of a routed packet. sFlow | 1397