Cisco Nexus 3548 - Configuring SPAN Truncation

Configuring SPAN Truncation
You can configure truncation for local and ERSPAN-source sessions only.
Procedure
PurposeCommand or Action
Enters global configuration mode.switch# configure terminal
Step 1
Enters monitor configuration mode for the specified
SPAN session.
switch(config)# monitor session
session-number
Step 2
Configures port channel or VLAN sources. For
VLAN sources, the monitored direction is implicit.
switch(config-monitor) # source
{interface {port-channel}
channel-number [rx | tx | both] | vlan
vlan-range}
Step 3
Configures the MTU size for truncation. Any SPAN
packet that is larger than the configured MTU size
switch(config-monitor) # mtu size
Step 4
is truncated to the configured size with a 4-byte
offset.
The MTU truncation size is between 64 bytes and
1518 bytes.
Configures the Ethernet SPAN destination port.switch(config-monitor)# destination
interface ethernet slot/port
Step 5
The following example shows how to configure MTU truncation for a local session:
switch# configure terminal
switch(config)# monitor session 5
switch(config-monitor)# source interface ethernet 1/5 both
switch(config-monitor)# mtu 512
switch(config-monitor)# destination interface Ethernet 1/39
switch(config-monitor)# no shut
switch(config-monitor)# show monitor session 5
session 5
---------------
type : local
state : down (No operational src/dst)
mtu : 512
source intf :
rx : Eth1/5
tx : Eth1/5
both : Eth1/5
source VLANs :
rx :
destination ports : Eth1/39
Legend: f = forwarding enabled, l = learning enabled
Cisco Nexus 3548 Switch NX-OS System Management Configuration Guide, Release 6.x
152
Configuring SPAN
Configuring SPAN Truncation