mes grow, there is a choice to be made: Continue integrating network nodes in the same site, maintaining the ease of implementation and operations, at the expense of having a crowded site, not SO easy to work on, besides an increasing exposure to any kind of service outage risk. Deploy the new network elements in a newly created site, lowering the exposure to total network service outage risks, enabling a more comfortable deployment and operation, at the expense of the increased costs and time constraints of having another operational site for core network operations. Ultimately, the final decision will also be an optimisation outcome, in this case not SO much related to technical-only aspects but rather to technical-operational-economic aspects. In any case, it is sensible to have the optimisation team participating in this type of exercise. Packet Core Network Optimisation In the case of networks covering large geographical areas, in extensive countries, no matter what the coverage density is, the problematic is different, although the topological optimisation opportunities are actually more evident. Topology aspects to be considered for an optimised configuration include proper connectivity design from the serving network nodes to the main data centres. Also, the access to delay sensitive types of services has to be taken into account, particularly if the latency of the backbone network starts to become an obstacle to delivery of certain data services. A careful analysis of centralised and distributed types of architecture, including also the nontechnical factor, and proving the technical feasibility of both options will be the main tool for design optimisation. In this case, physical topology has been considered. However, there are also some optimisation op- portunities arising from logical topology, specifically referring to connectivity optimisation, that might well follow into the category of backbone optimisation, closer to the IT world as such. Additional as- pects subject to this type of optimisation al