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

Configuring ERSPAN
Step 12

Configuring MTU Truncation for Each ERSPAN Session

Beginning with Cisco NX-OS Release 6.1, in order to reduce the ERSPAN traffic bandwidth, you can configure
the maximum bytes allowed for each replicated packet in an ERSPAN session. This value is called the
maximum transmission unit (MTU) truncation size. Any ERSPAN packet larger than the configured size is
truncated to the configured size.
Note MTU truncation and ERSPAN sampling can be enabled at the same time and have no precedence over
each other because they are applied to different aspects of the source packet (size versus packet count).
Do not enable MTU truncation if the destination ERSPAN router is a Cisco Catalyst 6000 Series switch
Note
because the Cisco Catalyst 6000 Series switch drops these truncated packets.
Before You Begin
Ensure that you are in the correct VDC (or use the switchto vdc command).
Procedure
Step 1
Step 2
Step 3
Step 4
Step 5
Step 6
Command or Action
switch(config)# copy running-config
startup-config
Command or Action
switch# configure terminal
switch(config)# monitor session
session-number type erspan-source
switch(config-erspan-src)#
header-type version
switch(config-erspan-src)# [no] mtu
mtu
switch(config-erspan-src)# exit
switch(config)# exit
Cisco Nexus 7000 Series NX-OS System Management Configuration Guide
Configuring MTU Truncation for Each ERSPAN Session
Purpose
(Optional)
Copies the running configuration to the startup
configuration.
Purpose
Enters global configuration mode.
Enters the monitor configuration mode for the ERSPAN
source type and specifies the ERSPAN session for which
the MTU truncation size is to be configured.
(Optional)
Changes the ERSPAN source session from Type II to
Type III.
Configures the MTU truncation size for packets in the
specified ERSPAN session. The range is from 176 to
1500 bytes.
Exits monitor configuration mode.
Exits global configuration mode.
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