Duplicate nicknames between adjacent IS-IS areas are not supported.
If a duplicate nickname exists between adjacent areas, the boundary node logs an event like the following:
GlobalRouter ISIS WARNING Duplicate Nickname f.f0.3c detected on Boundary Node between SysId 4088.2fe9.8884 (REMOTE area) and SysId f4ce.48a1.f084 (HOME area)
To recover from this event and ensure the information on the boundary node is correctly updated, you must perform the following tasks:
Change the nickname on both of the conflicting nodes.
Disable and re-enable IS-IS on both of the conflicting nodes.
Delete errors can display on the boundary node but they have no functional impact.