This is a double socket. The identifiers are written together on a sticker on the socket. This is how to decipher them:
|Network socket identifier||Cross connect cabinet identifier|
These numbers mean that the socket is located at the B1:216 beam in the B1:2 corridor. The cross connect cabinet serving this network socket is located in C1:2 and in this case the rack called C1-D202 in the panel number 1 and socket number 3 and 4.
Some of the sockets have room numbers instead of beam numbers where the beam numbers are not applicable.