e running networks. Some dimensioning parameters are as listed below: Percentage of simultaneous attached subscribers Percentage of simultaneous active data subscribers Core Network Planning and Optimisation Average number of PDP context activations per subscriber during the BH (busy hour) Average number of PDP context deactivations per subscriber during the BH Average traffic demand (at the IP layer) per active data subscriber at the BH and downlink + uplink Ratio of downlink/(downlink + uplink) Number of intra-SGSN routing area updates Number of inter-SGSN routing area updates Mode of connection to the Internet/Intranet/ISP Ratio of transparent/(transparent + nontransparent) Percentage of class A, B and C mobile stations Number of DNS requests per subscriber during the BH Number of DHCP requests per subscriber during the BH Number of CDRs per subscriber per day Inter-PLMN roaming traffic: percentage of total Gn traffic Average packet size (bytes) Gn interface overhead Gb interface overhead GPRS data traffic per subscriber during the BH in bps EDGE data traffic per subscriber during the BH in bps SGSN Dimensioning The process will start again from the BSS/RAN side, the ultimate location of both sources of input, traffic and amount of subscribers. It is important to be familiar beforehand with the main characteristics and features of the type of SGSN to be deployed. The main process can be defined as finding out how many SGSNs are needed in a given core network site at a given point of the roll-out timeline to serve the previously calculated traffic from both sides, BSS/RAN and backbone, and, of course, for the expected amount of subscribers at that point of time. The most obvious limiting factors affecting the capacity of a generic SGSN node are the number of GPRS attached subscribers to the served, simultaneous active PDP contexts and the data throughput. Data throughput is obtained as a result of the interface dimensioning exercise, whereas the amount of subscribers to be served is an input from the roll-out p