ready in place, we can measure the components of the MSC processor load. We know how many calls per hour these base stations are generating, so we know the call- processing activity. We know how many short messages are being sent from each base station, so we can add them up for a total SMS load. We know how many handoffs these base stations are doing, and we can use that handoff activity. Thus we have a good han- dle on the amount of MSC processing power we will need. Backhaul is also easy. We can look at the current backhaul requirements of the base stations in the new MSC region. The backhaul requirement of the base stations does not change with a change in MSC, SO we can add up the total backhaul for the new MSC region. Transport to public and private networks requires more than just a total of existing resources. We have to estimate the amount of PSTN, PPDN, and private network traf- fic for the base stations being served by the MSC. If the service mix across the wireless telephone system is fairly uniform, then we can use the number of base stations to es- timate the voice traffic for the PSTN and the data traffic for the PPDN. We should be able to calculate the private network traffic based on contracts. We can do traffic engi- neering exercises for voice and packet data to figure out how much transport we need. We need to estimate the number of loopback trunks for mobile-to-mobile calls within the new MSC region. Since these calls can overflow to the PSTN, admittedly at higher Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Mobile Switching Center (MSC) Growth Mobile Switching Center (MSC) Growth cost, we can start the new MSC out with a good estimate and see if we have enough loopback trunks. We recommend taking the amount of loopback traffic on the old MSCs, figuring out the proportional share for the new MSC region, which may be s