This Recommendation specifies the physical, procedural and protocol requirements for interfaces at the VB5.2 reference point between an Access Network (AN) and a Service Node (SN). The VB5.2 reference point provides flexible (provisioned) Virtual Path (VP) link allocation and flexible (provisioned) Virtual Channel (VC) link allocation (controlled by the 43 interfaces) as well as on-demand VC link allocation controlled by the SN via the Broadband Bearer Connection Control(B-BCC) protocol. That is the VB5.2 reference point is a superset of the VB5.1 reference point, enabling on-demand VC link allocation in the AN and across the VB5 reference point via the additional B-BCC function.
ITU-T G.967.2 SPANISH-1999 history
1999ITU-T G.967.2 SPANISH-1999 V-interfaces at the service node (SN): VB5.2 reference point specification