Configuring Mtu Truncation For Each Span Session - Cisco Nexus 7000 Series Configuration Manual

Configuring SPAN
Step 6

Configuring MTU Truncation for Each SPAN Session

To reduce the SPAN traffic bandwidth, you can configure the maximum bytes allowed for each replicated
packet in a SPAN session. This value is called the maximum transmission unit (MTU) truncation size. Any
SPAN packet larger than the configured size is truncated to the configured size.
Note MTU truncation and the SPAN rate limit cannot be enabled for the same SPAN session on F1 Series
modules. If you configure both for one session, only the rate limit is allowed on F1 Series modules, and
MTU truncation is disabled until you disable the rate limit configuration. This limitation does not apply
to F2 and M2 Series modules or Supervisor 2.
MTU truncation and SPAN sampling can be enabled at the same time and have no precedence over each
Note
other because they are applied to different aspects of the source packet (size versus packet count).
Before You Begin
Ensure that you are in the correct VDC (or use the switchto vdc command).
Procedure
Step 1
Step 2
Step 3
Command or Action
copy running-config startup-config
Example:
switch(config)# copy
running-config startup-config
Command or Action
configure terminal
Example:
switch# configure terminal
switch(config)#
monitor session session-number
Example:
switch(config)# monitor session 3
switch(config-monitor)#
[no] mtumtu
Example:
switch(config-monitor)# mtu 64
Cisco Nexus 7000 Series NX-OS System Management Configuration Guide
Configuring MTU Truncation for Each SPAN Session
Purpose
(Optional)
Copies the running configuration to the startup
configuration.
Purpose
Enters global configuration mode.
Enters the monitor configuration mode and specifies
the SPAN session for which the MTU truncation
size is to be configured.
Configures the MTU truncation size for packets in
the specified SPAN session. The range is from 64
to 1500 bytes.
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