 for deployment, the traffic volume of the urban areas and the routing areas definition on the GPRS network should also be understood correctly. Once more, previous experience of SMS traffic and its geographical distribution may be a help. An increase in the number of MMS coming from and going to a different PLMN can be expected, particularly with operators from different countries. The MMS will play a role similar to that of traditional postcards for tourists on holiday. This can be taken into account when studying the roaming strategy. Subscriber Growth Estimates This is the key input in terms of definition of a rollout plan for the MMSC, and its impact in the expansion of the existing GPRS. It can be expected to be provided from customer data, usually in the format of a table as shown in Figure B.4. MMS Configuration Issues The MMSC solution and servers can be defined in various formats. Therefore, MMS config- uration plays a major role in the overall planning process. Site connectivity is also heavily affected by the integration of MMS. Site Definition The MMS solution is to be integrated within the core site, and connectivity has to be defined both at both physical and logical levels. A cluster configuration involves additional complexity for connectivity. The server or cluster has to be integrated into the Gi VLAN. The connectivity to the Gi is created through the associated WAP gateway. Since the MMS system connectivity is to be established at the internal Gi interface, we can assume that there could be a requirement for physical connectivity to the local site switches. If the system presents a cluster solution, the corresponding load balancing switch can be placed before connecting the switch. Redundancy and Load Balancing The redundancy of the solution depends heavily on the redundancy of the servers. A cluster architecture for larger systems enables more options for physical connectivity redundancy. The use of load balancing switches is another of the key issues to be considered. From a planning point o