Administrator Guide

sFlow on LAG ports
When a physical port becomes a member of a LAG, it inherits the sFlow configuration from the LAG port.
Enabling Extended sFlow
Extended sFlow packs additional information in the sFlow datagram depending on the type of sampled packet.
You can enable the following options:
● extended-switch — 802.1Q VLAN ID and 802.1p priority information.
● extended-router — Next-hop and source and destination mask length.
● extended-gateway — Source and destination AS number and the BGP next-hop.
NOTE: The entire AS path is not included. BGP community-list and local preference information are not included. These
fields are assigned default values and are not interpreted by the collector.
● Enable extended sFlow.
sflow [extended-switch] [extended-router] [extended-gateway] enable
By default packing of any of the extended information in the datagram is disabled.
● Confirm that extended information packing is enabled.
show sflow
The bold line shows that extended sFlow settings are enabled on all three types.
Dell#show sflow
sFlow services are enabled
Global default sampling rate: 4096
Global default counter polling interval: 15
Global extended information enabled: gateway, router, switch
1 collectors configured
Collector IP addr: 10.10.10.3, Agent IP addr: 10.10.0.0, UDP port: 6343
77 UDP packets exported
0 UDP packets dropped
165 sFlow samples collected
69 sFlow samples dropped due to sub-sampling
Linecard 1 Port set 0 H/W sampling rate 8192
Gi 1/16: configured rate 8192, actual rate 8192, sub-sampling rate 1
Gi 1/17: configured rate 16384, actual rate 16384, sub-sampling rate 2
Linecard 3 Port set 1 H/W sampling rate 16384
Gi 3/40: configured rate 16384, actual rate 16384, sub-sampling rate 1
If you did not enable any extended information, the show output displays the following (shown in bold).
Dell#show sflow
sFlow services are disabled
Global default sampling rate: 32768
Global default counter polling interval: 20
Global extended information enabled: none
0 collectors configured
0 UDP packets exported
0 UDP packets dropped
0 sFlow samples collected
0 sFlow samples dropped due to sub-sampling
Important Points to Remember
● If the IP source address is learned via IGP, srcAS and srcPeerAS are zero.
● The srcAS and srcPeerAS might be zero even though the IP source address is learned via BGP. The c system packs the
srcAS and srcPeerAS information only if the route is learned via BGP and it is reachable via the ingress interface of the
packet.
The previous points are summarized in following table.
906
sFlow