It is not a protocol. It is a table containing the b numbers & the route where they should be routed to. When a call is made, the exchange would like into the B table. If the number is available, it would take the route & connect your call.
The B-Table include all the numbering plane that the subscriber will call as example if the subscriber call 00201112853 an Egypt number (international) so first its will inserted in the b-number to analyze this number to route it to the correct route( the route include traffic time slots).
The relation between the b-table and the EOS is that an example if the b number was no in the b-table the EOS code will be generated and will be analyzed also in EOS table to generate the correct announcement
B number table for Ericsson like MOTOROLA Trnaslation.However,B number table have RC to HLR for Own PLMN and than Selection for MSC(If More MSC in that PLMN).Otherwise call will go to POI defined with taht MSC or another MSC.
Before B-Number table,MSC analyzing the Pre analysis,number taken from A number.by PNBSP you can see the pre analysis table.