[Become superuser on any node.]
[Enter the scsetup utility:]
# scsetup
[Enter option 8:]
*** Cluster Interconnect Menu ***
    Please select from one of the following options:
    ...
      8) Disable a transport cable
    ...
    Option: 8
[Enter the requested information:]
>>> Disable a Cluster Transport Cable <<<
    ...
    Is it okay to continue (yes/no) [yes]? <Return>
    ...
    To which node is the cable attached? phys-schhost-2
    Name of the adapter on "phys-schost-2"? qfe-1
    Is it okay to proceed with the update (yes/no) [yes]? <Return>

scconf -c -m endpoint=phys-schost-2:qfe1,state=disabled

    Command completed successfully.
    Hit ENTER to continue: <Return>
[Verify that the cable is disabled:]
# scconf -p | grep cable
  Transport cable:   phys-schost-2:qfe1@0 ethernet-1@2    Disabled
  Transport cable:   phys-schost-3:qfe0@1 ethernet-1@3    Enabled
  Transport cable:   phys-schost-1:qfe0@0 ethernet-1@1    Enabled