Users Guide

sFlow

sFlow monitoring system includes an sFlow Agent and an sFlow Collector.

• The sFlow Agent combines the ow samples and interface counters into sFlow datagrams and forwards them to the sFlow Collector.

• The sFlow Collector analyses the sFlow Datagrams received from the dierent devices and produces a network-wide view of trac

ows.

Important Points to Remember

• Dell Networking OS recommends that the sFlow Collector be connected to the Dell Networking chassis through a line card port rather

than the route processor module (RPM) Management Ethernet port.

• The system exports all sFlow packets to the sFlow Collector. A small sampling rate can equate to many exported packets. A backo

mechanism is automatically applied to reduce this amount. Some sampled packets may be dropped when the exported packet rate is

high and the backo mechanism is about to or is starting to take eect. The dropEvent counter, in the sFlow packet, is always zero.

• sFlow sampling is done on a per-port basis.

• Community list and local preference elds are not lled up in the extended gateway element in the sFlow datagram.

• The 802.1P source priority eld is not lled up in the extended switch element in the sFlow datagram.

• Only Destination and Destination Peer AS numbers are packed in the dst-as-path eld in the extended gateway element.

• If the packet being sampled is redirected using policy-based routing (PBR), the sFlow datagram may contain incorrect extended

gateway/router information.

• The source virtual local area network (VLAN) eld in the extended switch element is not packed if there is a routed packet.

• The destination VLAN eld in the extended switch element is not packed if there is a multicast packet.

• The maximum number of packets that can be sampled and processed per second is:

– 7500 packets when no extended information packing is enabled.

– 7500 packets when only extended-switch information packing is enabled (refer to sow extended-switch enable).

– 1600 packets when you enable extended-router and/or extended-gateway information packing

Topics:

• sow collector

• sow enable (Global)

• sow ingress-enable

• sow extended-switch enable

• sow max-header-size extended

• sow polling-interval (Global)

• sow polling-interval (Interface)

• sow sample-rate (Global)

• sow sample-rate (Interface)

• show sow

• show sow stack-unit

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