Users Guide

sFlow
The Dell Networking OS supports sFlow commands.
The Dell Networking OS 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 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.
• Dell Networking OS 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.
• sFlow does not support packing extended information for IPv6 packets. Only the rst 128 bytes of the IPv6 packet is shipped in the
datagram.
• 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 sFlow sampling functionality is supported only for egress trac and not for ingress trac.
• 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 (see sow extended-switch enable).
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
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