Reference Guide

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.
• Community list and local preference fields are not filled in extended gateway element in the sFlow datagram.
• 802.1P source priority field is not filled in extended switch element in sFlow datagram.
• Only Destination and Destination Peer AS number are packed in the dst-as-path field in 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.
• The source virtual local area network (VLAN) field in the extended switch element is not packed in case of
routed packet.
• The destination VLAN field in the extended switch element is not packed in a Multicast packet.
• Up to 700 packets can be sampled and processed per second.
Enabling Extended sFlow
The S-Series platforms support extended-switch information processing only.
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.
Example of Verifying Extended sFlow is Enabled
FTOS#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).
734