Service Manual

51
sFlow
The Dell Networking operating software (OS) supports sFlow commands on Dell Networking OS.
Dell Networking operating software 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 operating software 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 (refer to sow extended-switch enable).
sow collector
Congure a collector device to which sFlow datagrams are forwarded.
Syntax
sflow collector {ip-address | ipv6-address} agent-addr {ip-address | ipv6-
address} [number [max-datagram-size number]] | [max-datagram-size number]
[vrf management]
1346
sFlow