SDP is service data point and is a database system in telecom network. This node or database is used to contain the database with subscriber and account information. This is used in telecom prepaid charging and comes under intelligent network.
SDP contains data related to charging of voice and data calls of subscriber. Every time, a prepaid number make voice or data call, SDP comes in picture. SDP check subscriber current balance and give instruction to MSC.
SDP holds and keep check of the data like subscriber life cycle, dedicated account data, promotion plan data, tariff and charging analysis data, announcement class data, and community data.
SDP is connected to some other nodes like AIR (Account refill system), Voucher Server, charging control node, Admin, SGSN, GGSN, SCP, MSC and SMSC using different protocols like SMPP, RPC, CAP and SCAP.