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Making Configuration Changes on a Nexus 5500 Platform

By January 30, 2014November 13th, 2020Best Practices, Blog
Below you will find configuration examples for the Cisco Nexus 5500.  These are basic commands on entering in a configuration mode and saving a configuration change.  These are the most common tasks that will be performed.
Configuration modes:
On the Nexus switches there are two configuration modes, configure terminal and configure sync.
Configure Termial
The “configure terminal” mode is used whenever a change that is being made is just for one system or the other.  Any of the ports that are on the Nexus chassis would have configuration changes in this mode.  Example of the changes for a switch port (on the Nexus chassis) into a standard trunk port configuration.
  1. Log in to Cisco Nexus switch by SSH into it
  2. Enter your username/password
  3. Enter in the following commands to enter configuration terminal mode
    1. config terminal ###Moves the CLI into a terminal configuration mode.  Changes will be made to this node only and are active immediately.
    2. interface Ethernet1/18  ### Enter in the port you want to make configurations changes to.
    3. description –axis01  ### Adds a comment or description of the ports use.
    4. switchport mode trunk ###Turns the switch port into a Dot1q trunk port
    5. switchport trunk allowed vlan 100,113  ###  Forces the trunk port to only allow VLANs 100 and 113 through
    6. spanning-tree port type normal  ###Defines spanning-tree to go through the listening, learning, blocking and forwarding stages of loop protection.
  4. After entering in the needed configuration, leave the configuration mode.
    1. end ### This will leave the configuration mode.
  5. Save the configuration changes, in case of a system reboot.
    1. copy running-config startup-config ### Saves the current configuration to the one that will be used if the system restarts.
Configure Sync
The configure sync mode is used when a change would be made to both sides or a port on an attached Fiber Extender FEX switch. 
  1. Log in to Cisco Nexus switch by SSH into it
  2. Enter your username/password
  3. Enter in the following commands to enter configuration sync mode
    1. config sync ###Moves the CLI into a synchronized configuration mode.  Changes will be made to both sides of the cluster when commited.
    2. switch-profile PEI  ###Moves the CLI into the switch-profile to buffer the changes to be made.
  4. At this time switch changes can be made, but the changes will not take affect till the changes are committed.
Below are the steps needed to commit a change:
  1. Follow the steps to log in to the switch.
  2. Type the following commands to enter configuration sync mode in the proper switch profile
    1. configure sync
    2. switch-profile PEI
    3. show switch-profile PEI status  ###Shows the current state of the replication of changes across the cluster.
    4. show switch-profile PEI buffer ###Shows the changes in queue to be made when commited.
    5. verify   ###Will check to ensure there are no conflicts with the changes to existing configuration.
    6. commit   ###Will make the changes active and push the changes to both sides of the cluster.
Here is an example of a configuration modification to an attached FEX port.  For this example we are modifying the 10th port on the FEX 104.
  1. Follow the step to log in to the switch
  2. Type the following command to enter configure sync mode and enter into the SP switch-profile
    1. configure sync
    2. switch-profile PEI
  3. Enter in the port changes that need to be made
    1. interface Ethernet104/1/10 ### Move the CLI to the interface that you need to make changes on.
    2. switchport access vlan 100 ### Changes the port to expect traffic with no VLAN tag, and tag it with the VLAN tag of 100
    3. spanning-tree port type edge ### Turns off spanning-tree and puts the port into a portfast mode.
  4. The changes that have been made are now in the switch-profile buffer.  To view the changes, we will need to show the contents of this buffer.
    1. show switch-profile PEI buffer ###Shows all changes to be made when switch-profile is committed
  5. To make the changes active across both sides of the cluster, we need to commit the changes.
    1. commit ###Makes all modification in the switch-buffer active to both sides of the cluster.

Jason Howe, PEI

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