- Welcome to the Cisco Nexus 3550T Programmable Switch Platform Documentation
-
- Command Line Interface
- Bash Shell
- System Clock
- AAA Configuration
- Configuration Management
- Automatic Configuration
- Configuring Interfaces
- Layer 2 Configuration
- Layer 3 Configuration
- Port Channel Configuration
- VRRP Configuration
- SNMP
- SPAN/Monitoring Configuration
- High Precision Timestamping
- Diagnostics
- System Logs
- Debug Dumps
- Statistics Logging
- FPGA Firmware Selection
- Known Issues
SPAN Configuration
Cisco Nexus 3550-T Programmable Switch Platform allows users to create a SPAN or monitoring session, which allows monitoring of the incoming frames coming on the source ports of the SPAN session by directing them to the destination port. A SPAN session consists of a set of source ports which are getting monitored for the incoming traffic and a destination port which can be connected to the frame analyzer to analyze the frames.
Note
The frame analyzer is an external device and is not part of Nexus 3550-T.
Create SPAN session
The Nexus 3550-T enables users to create SPAN session by using the CLI.
To create a SPAN session, use the following command:
admin@NX-3550-T# configure monitor session 1
admin@NX-3550-T(config-mo-1)#
The above command creates a SPAN session with id 1. The allowed range of the SPAN session id is from 1 to 24.
Adding source port to SPAN session
The Nexus 3550-T allows monitor of the incoming frames on the source ports of a SPAN session. The source port can be either a physical port or it can also be a port-channel. If the source port is a port-channel then the traffic coming on all the member ports of the port-channel will be directed to the SPAN output port.
To configure the source port in a SPAN session the following command is used:
admin@NX-3550-T(config-mo-1)# source interface port-channel1
The alternate command to achieve the same outcome is: admin@NX-3550-T# configure monitor session 1 source interface port-channel1
To configure a port-channel as source port the following command is used:
admin@NX-3550-T(config-mo-1)# source interface port-channel1
To configure a physical interface as source port the following command is used:
admin@NX-3550-T(config-mo-1)# source interface et1-3
The above command will configure multiple interfaces as source interfaces of the monitoring session.
Adding destination port to SPAN session
The Nexus 3550-T allows the users to configure destination port which will receive all the incoming frames on the source ports of a SPAN session. The destination port must a physical port. It can't be a port-channel or virtual port. Also, if a port is configured as destination port in a session it can't be configured as destination port in any other SPAN session.
To configure the destination port in a SPAN session the following command is used:
admin@NX-3550-T(config-mo-1)# destination interface et4
The above command will configure the ethernet4 interface as the destination port in the SPAN session 1.
Adding description to SPAN session
The Nexus 3550-T allows the users to add the description about the SPAN session which can include the details about the SPAN session like what is the objective of this SPAN session. It could be that one session is used to monitor the NAT traffic so the users can specify that in the description.
To add the description for a SPAN session the following command is used:
admin@NX-3550-T(config-mo-1)# destination "Monitor multicast traffic."
The above command will configure the description in the SPAN session 1. By default, no description is defined.
Enabling the SPAN session
By default when a SPAN session is created, it gets created in disabled mode. The Nexus 3550-T allows the users to enable the SPAN session using the CLI. Unless the SPAN session is enabled the packets coming on source port will not be pushed to the destination port.
To enable the SPAN session the following command is used:
admin@NX-3550-T(config-mo-1)# no shutdown
The above command will enable the SPAN session 1 which allows the frames coming on source ports to be directed to the destination port. By default, SPAN session starts in shutdown mode.
NoteThe frames at SPAN output may have some of the fields like destination MAC, source/destination ip/port updated.
Display the SPAN session
To dump all the configured SPAN session use the following command:
admin@NX-3550-T(config)# show monitor
monitor session destination interface source interface
--------------- --------------------- -------------------------
1 ethernet7 ethernet5; port-channel1
The Nexus 3550-T allows the users to dump a specific SPAN session using the following CLI command:
admin@NX-3550-T(config)# show monitor session 1
monitor session 1
source interface ethernet5 port-channel1
destination interface ethernet7
no shutdown
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