B Link
Bridge link
Bridge link is a SL (Signalling Link) that connects an STP (Signalling Transfer Point) to another STP. Typically a quad of B links interconnect peer (or primary) STPs (e.g. the STPs from one network to the STPs of another network). The distinction between a B link and a D link is rather arbitrary. For this reason such links may be referred to as B/D links.