This read-only value reports whether this Gigabit Ethernet port is assigned to an inter-node (multishelf) link connecting this shelf to another shelf over external fiber. Admins check it to identify which physical ports on the shelf are dedicated to shelf-to-shelf interconnection rather than regular client or line traffic. For example, seeing this enabled on a given port confirms that port is carrying inter-shelf link traffic rather than being available for a standard service connection.