Manual peer assignment for ambiguous peer-keepalive IP addresses

Cisco Nexus switches that form a virtual port channel (vPC) pair use a peer-keepalive IP address to identify partner devices. NCM uses information from the downloaded device configurations to determine which devices are paired. If NCM cannot determine which device is paired with another, the device is marked as "ambiguous". This can happen if more than one device uses the same peer-keepalive IP address.

When a device is marked as ambiguous, you can manually specify its peer. A manually assigned peer always takes precedence over automatic detection. The specification is saved permanently, and it can be changed or removed at any time.

After significant network changes (for example, replacing a device or re-cabling), review any existing manual assignments. An existing assignment will continue to be paired with a manually assigned device even if it is no longer the correct partner.

Requirements

Manual assignment requires information from downloaded device configurations. It does not use polled data. For a device to be manually paired:

• A configuration must be downloaded from the local Nexus device. NCM reads the peer-keepalive IP address from the downloaded config.

• Configurations must be downloaded for every Nexus device that could be the partner. When you manually pair a device, the list of devices you can choose from includes only devices with downloaded, parsed configurations.

• A configuration must be downloaded for the device you select. When you save your choice, NCM examines the selected device's configuration. If that device has no usable configuration, the manual assignment cannot be saved.

If a device is manually paired and then later that device loses its configuration, the manual assignment is retained. However, a new assignment cannot be created without configuration data.

Manually assign a peer

1. Open the Node Details page for the monitored Cisco Nexus device.

2. In the side menu, click vPCs to open the vPCs view.

3. Click the Manual assignment option in the toolbar.

   The Manual assignment button is displayed in the following circumstances:

   • The device's peer-keepalive address has more than one possible peer, and so the peer can't be automatically assigned.

   • A peer was manually assigned previously, and a user might want to edit or remove the assignment.

   If NCM can identify the peer, or if there is only one possible candidate, the Manual assignment option is not available.

   The Manual Assignment dialog box displays the peer-keepalive address read from the local device's configuration. A dropdown menu lists the remote nodes you can pair it with. Remote devices are listed with their device name followed by the node ID in parentheses. The device with the most recently downloaded configuration is listed first.

4. Select the device you want to manually assign from the dropdown menu, and then click Save.

   The Node Details page is updated and reloaded.

Change a manual assignment

1. Open the Node Details page for the monitored Cisco Nexus device.

2. In the side menu, click vPCs to open the vPCs view.

3. Click the Manual assignment option in the toolbar.

   The Manual Assignment dialog box opens.

4. Select a different device from the dropdown menu, and then click Save.

   The Node Details page is updated and reloaded.

Remove a manual assignment

1. Open the Node Details page for the monitored Cisco Nexus device.

2. In the side menu, click vPCs to open the vPCs view.

3. Click the Manual assignment option in the toolbar.

   The Manual Assignment dialog box opens.

4. Click Remove.

   The Remove button is available only when the device currently has a manually assigned peer.

   After the removal, NCM attempts to identify the partner. If the partner cannot be identified automatically, the device status goes back to ambiguous and the Manual assignment option is available again. The remote device that was unassigned is now available to be paired with other devices.