Administrator 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 dierent devices and produces a network-wide view of trac
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 eect. 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 trac and not for ingress trac.
• 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 sow extended-switch enable).
Topics:
• sow collector
• sow enable (Global)
• sow ingress-enable
• sow extended-switch enable
• sow max-header-size extended
• sow polling-interval (Global)
• sow polling-interval (Interface)
• sow sample-rate (Global)
• sow sample-rate (Interface)
• show sow
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