Configuration Guide User guide

FastIron Configuration Guide 541
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sFlow
Specifying an sFlow collector on IPv6 devices
To specify an sFlow collector on an IPv6 device, enter a command such as the following.
Brocade(config)#sflow destination ipv6 2003:0:0::0b:02a
This command specifies a collector with IPv6 address 2003:0::0b:02a, listening for sFlow data on
UDP port 6343.
Syntax: [no] sflow destination ipv6 <ip-addr> [<dest-udp-port>]
The <ip-addr> parameter specifies the IP address of the collector.
The <dest-udp-port> parameter specifies the UDP port on which the sFlow collector will be listening
for exported sFlow data. The default port number is 6343.
If the IPv6 address you specify is a link-local address on a Layer 3 switch, you must also specify the
outgoing-interface ethernet <port-num> or the ve <port-num>. This identifies the outgoing
interface through which the sampled packets will be sent.
The sampled sFlow data sent to the collectors includes an agent_address field. This field identifies
the device that sent the data. Refer to “sFlow and source address” on page 537.
Changing the polling interval
The polling interval defines how often sFlow byte and packet counter data for a port are sent to the
sFlow collectors. If multiple ports are enabled for sFlow, the Brocade device staggers transmission
of the counter data to smooth performance. For example, if sFlow is enabled on two ports and the
polling interval is 20 seconds, the Brocade device sends counter data every ten seconds. The
counter data for one of the ports are sent after ten seconds, and counter data for the other port are
sent after an additional ten seconds. Ten seconds later, new counter data for the first port are sent.
Similarly, if sFlow is enabled on five ports and the polling interval is 20 seconds, the Brocade
device sends counter data every four seconds.
The default polling interval is 20 seconds. You can change the interval to a value from 1 to any
higher value. The interval value applies to all interfaces on which sFlow is enabled. If you set the
polling interval to 0, counter data sampling is disabled.
To change the polling interval, enter a command such as the following at the global CONFIG level of
the CLI.
Brocade(config)#sflow polling-interval 30
Syntax: [no] sflow polling-interval <secs>
The <secs> parameter specifies the interval and can be from 1 to any higher value. The default is
20 seconds. If you specify 0, counter data sampling is disabled.
Changing the sampling rate
The sampling rate is the average ratio of the number of packets incoming on an sFlow-enabled
port, to the number of flow samples taken from those packets.
You can change the default (global) sampling rate. You also can change the rate on an individual
port, overriding the default sampling rate of 512. With a sampling rate of 512, on average, one in
every 512 packets forwarded on an interface is sampled.