Reference Guide

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sFlow
Dell Networking OS supports sFlow commands on the S5000 switch.
Dell Networking OS 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 analyzes the sFlow Datagrams received from the different devices and produces
a network-wide view of traffic flows.
Important Point to Remember
Dell Networking recommends that the sFlow Collector be connected to the Dell Networking chassis
through the interface rather than the Management Ethernet interface.
Dell Networking OS exports all sFlow packets to the sFlow Collector. A small sampling rate can equate
to a large number of exported packets. A backoff mechanism is automatically 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, is always 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 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 first 128 bytes of the
IPv6 packet is shipped in the datagram.
The source virtual local area network (VLAN) field in the extended switch element is not packed in
case of a routed packet.
The destination VLAN field in the extended switch element is not packed in case of 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 sflow
extended-switch enable).
1600 packets when extended-router and/or extended-gateway information packing is enabled.
sFlow
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