Quick Reference Guide

PowerConnect B-Series TI24X Configuration Guide 1081
53-1002269-02
sFlow
A
IPv6 packet sampling
IPv6 sampling is performed by the packet processor. The system uses the sampling rate setting to
selectively mark the monitoring bit in the header of an incoming packet. Marked packets tell the
CPU that the packets are subject to sFlow sampling.
Configuration considerations
This section lists the sFlow configuration considerations on devices.
Hardware support
• Devices support sFlow packet sampling of inbound traffic only. These devices do not sample
outbound packets. However, devices support byte and packet count statistics for both traffic
directions.
• sFlow is supported on all Ethernet ports (10/100, Gbps, and 10 Gbps)
CPU utilization
Enabling sFlow may cause a slight and noticeable increase of up to 20% in CPU utilization. In
typical scenarios, this is normal behavior for sFlow, and does not affect the functionality of other
features on the switch.
Source address
The sampled sFlow data sent to the collectors includes an agent_address field. This field identifies
the IP address of the device that sent the data:
• On a Layer 2 Switch, agent_address is the Layer 2 Switch management IP address. You must
configure the management IP address in order to export sFlow data from the device. If the
switch has both an IPv4 and IPv6 address, the agent_address is the IPv4 address. If the switch
has an IPv6 address only, the agent_address is the global IPv6 address.
• On a Layer 3 Switch with IPv6 interfaces only, sFlow looks for an IPv6 address in the following
order, and uses the first address found:
• The first IPv6 address on the lowest-numbered loopback interface
• The first IPv6 address on the lowest-numbered VE interface
• The first IPv6 address on any interface
• On a Layer 3 Switch with both IPv4 and IPv6 interfaces, or with IPv4 interfaces only, sFlow
looks for an IP address in the following order, and uses the first address found:
• The IPv4 router ID configured by the ip router-id command
• The first IPv4 address on the lowest-numbered loopback interface
• The first IPv4 address on the lowest-numbered virtual interface
• The first IPv4 address on any interface
NOTE
The device uses the router ID only if the device also has an IP interface with the same address.
Router ID is not supported on IPv6 devices.