Broadcast domains are automatically created. However, if a port is recabled, or the switch configuration changes, a port might need to be repaired into a different broadcast domain (new or existing).

ONTAP can automatically detect and recommend solutions to network wiring issues based on a broadcast domain constituent’s (ethernet ports) layer-2 reachability.

Incorrect wiring during might cause an unexpected broadcast domain port assignment. Beginning with ONTAP 9.10.1, the cluster automatically checks for network wiring issues by verifying port reachability after cluster setup or when a new node joins an existing cluster.

ONTAP System Manager

If a port reachability issue is detected, ONTAP System Manager recommends a repair operation to resolve the issue.

After you set up the cluster, network wiring issues are reported on the Dashboard.

After joining a new node to a cluster, network wiring issues appear on the Nodes page.

You can also view network wiring health on the network diagram. Port reachability issues are indicated on the network diagram by a red error icon.

Post cluster setup

After you set up the cluster, if the system detects a network wiring issue, a message appears on the Dashboard.

Post cluster setup message

Steps

Correct the wiring as suggested in the message.
Click the link to launch the Update Broadcast Domains dialog.
The Update Broadcast Domains dialog opens.
Review the information about the port, including the node, the issues, the current broadcast domain, and the expected broadcast domain.
Select the ports that you want to repair and click Fix.
The system will move the ports from the current broadcast domain into the expected broadcast domain.

Post node join

After joining a new node to a cluster, if the system detects a network wiring issue, a message appears on the Nodes page.

Post node join message

Steps

Correct the wiring as suggested in the message.
Click the link to launch the Update Broadcast Domains dialog.
The Update Broadcast Domains dialog opens.
Review the information about the port, including the node, the issues, the current broadcast domain, and the expected broadcast domain.
Select the ports you want to repair and click Fix.
The system will move the ports from the current broadcast domain into the expected broadcast domain.

CLI

Before you begin

You must be a cluster administrator to perform this task.

About this task

A command is available to automatically repair the broadcast domain configuration for a port based on the layer 2 reachability detected by ONTAP.

Steps

Check your switch configuration and cabling.
Check the reachability of the port:

network port reachability show -detail -node -port

The command output contains reachability results.
Use the following decision tree and table to understand the reachability results and determine what, if anything, to do next.

Reachability-status	Description
ok	The port has layer 2 reachability to its assigned broadcast domain. If the reachability-status is "ok", but there are "unexpected ports", consider merging one or more broadcast domains. For more information, see the following Unexpected ports row. If the reachability-status is "ok", but there are "unreachable ports", consider splitting one or more broadcast domains. For more information, see the following Unreachable ports row. If the reachability-status is "ok", and there are no unexpected or unreachable ports, your configuration is correct.
Unexpected ports	The port has layer 2 reachability to its assigned broadcast domain; however, it also has layer 2 reachability to at least one other broadcast domain. Examine the physical connectivity and switch configuration to determine if it is incorrect or if the port’s assigned broadcast domain needs to be merged with one or more broadcast domains. For more information, see Merge broadcast domains.
Unreachable ports	If a single broadcast domain has become partitioned into two different reachability sets, you can split a broadcast domain to synchronize the ONTAP configuration with the physical network topology. Typically, the list of unreachable ports defines the set of ports that should be split into another broadcast domain after you have verified that the physical and switch configuration is accurate. For more information, see Split broadcast domains.
misconfigured-reachability	The port does not have layer 2 reachability to its assigned broadcast domain; however, the port does have layer 2 reachability to a different broadcast domain. You can repair the port reachability. When you run the following command, the system will assign the port to the broadcast domain to which it has reachability: `network port reachability repair -node -port`
no-reachability	The port does not have layer 2 reachability to any existing broadcast domain. You can repair the port reachability. When you run the following command, the system will assign the port to a new automatically created broadcast domain in the Default IPspace: `network port reachability repair -node -port` Note: If all interface group (ifgrp) member ports report `no-reachability`, running the `network port reachability repair` command on each member port would cause each one to be removed from the ifgrp and placed into a new broadcast domain, eventually causing the ifgrp itself to be removed. Prior to running the `network port reachability repair` command, verify that the port’s reachable broadcast domain is what you expect based on your physical network topology.
multi-domain-reachability	The port has layer 2 reachability to its assigned broadcast domain; however, it also has layer 2 reachability to at least one other broadcast domain. Examine the physical connectivity and switch configuration to determine if it is incorrect or if the port’s assigned broadcast domain needs to be merged with one or more broadcast domains. For more information, see Merge broadcast domains.
unknown	If the reachability-status is "unknown", then wait a few minutes and try the command again.

Reachability-status

Description

The port has layer 2 reachability to its assigned broadcast domain.
If the reachability-status is "ok", but there are "unexpected ports", consider merging one or more broadcast domains. For more information, see the following Unexpected ports row.

If the reachability-status is "ok", but there are "unreachable ports", consider splitting one or more broadcast domains. For more information, see the following Unreachable ports row.

If the reachability-status is "ok", and there are no unexpected or unreachable ports, your configuration is correct.

Unexpected ports

The port has layer 2 reachability to its assigned broadcast domain; however, it also has layer 2 reachability to at least one other broadcast domain.

Examine the physical connectivity and switch configuration to determine if it is incorrect or if the port’s assigned broadcast domain needs to be merged with one or more broadcast domains.

For more information, see Merge broadcast domains.

Unreachable ports

If a single broadcast domain has become partitioned into two different reachability sets, you can split a broadcast domain to synchronize the ONTAP configuration with the physical network topology.

Typically, the list of unreachable ports defines the set of ports that should be split into another broadcast domain after you have verified that the physical and switch configuration is accurate.

For more information, see Split broadcast domains.

misconfigured-reachability

The port does not have layer 2 reachability to its assigned broadcast domain; however, the port does have layer 2 reachability to a different broadcast domain.

You can repair the port reachability. When you run the following command, the system will assign the port to the broadcast domain to which it has reachability:

network port reachability repair -node -port

no-reachability

The port does not have layer 2 reachability to any existing broadcast domain.

You can repair the port reachability. When you run the following command, the system will assign the port to a new automatically created broadcast domain in the Default IPspace:

network port reachability repair -node -port

Note: If all interface group (ifgrp) member ports report no-reachability, running the network port reachability repair command on each member port would cause each one to be removed from the ifgrp and placed into a new broadcast domain, eventually causing the ifgrp itself to be removed. Prior to running the network port reachability repair command, verify that the port’s reachable broadcast domain is what you expect based on your physical network topology.

multi-domain-reachability

The port has layer 2 reachability to its assigned broadcast domain; however, it also has layer 2 reachability to at least one other broadcast domain.

Examine the physical connectivity and switch configuration to determine if it is incorrect or if the port’s assigned broadcast domain needs to be merged with one or more broadcast domains.

For more information, see Merge broadcast domains.

unknown

If the reachability-status is "unknown", then wait a few minutes and try the command again.

After you repair a port, check for displaced LIFs and VLANs. If the port was part of an interface group, you also need to understand what happened to that interface group.

LIFs

When a port is repaired and moved into a different broadcast domain, any LIFs that were configured on the repaired port will be automatically assigned a new home port. That home port is selected from the same broadcast domain on the same node, if possible. Alternatively, a home port from another node is selected, or, if no suitable home ports exist, the home port will be cleared.

If a LIF’s home port is moved to another node, or is cleared, then the LIF is considered to have been "displaced". You can view these displaced LIFs with the following command:

displaced-interface show

If there are any displaced LIFs, you must either:

Restore the home of the displaced LIF:

displaced-interface restore
Set the home of the LIF manually:

network interface modify -home-port -home-node
Remove the entry from the "displaced-interface" table if you are satisfied with the LIF’s currently configured home:

displaced-interface delete

VLANs

If the repaired port had VLANs, those VLANs are automatically deleted but are also recorded as having been "displaced". You can view these displaced VLANs:

displaced-vlans show

If there are any displaced VLANs, you must either:

Restore the VLANs to another port:

displaced-vlans restore
Remove the entry from the "displaced-vlans" table:

displaced-vlans delete

Interface groups

If the repaired port was part of an interface group, it is removed from that interface group. If it was the only member port assigned to the interface group, the interface group itself is removed.