Telephony Servers MULTI-SERVICE NETWORK TRAFFIC ENGINEERING A main difference between multi-service network (MSN) traffic engineering and engi- neering a traditional telephony network is that the MSN has to be dimensioned for a mixture of different types of traffic while the telephony network is dimensioned mainly for voice traffic. The fact that different types of traffic, e.g. voice and data, have totally different requirements on the network will of course have an impact on the dimensioning. OBJECTIVES The objectives of this chapter are to explain some general principles of dimensioning an MSN, and to give an example of a simplified dimensioning of an MSN, and in particular: To dimension: Interfaces: TDM circuit mode for voice and ATM for data and voice Real-time processing capacity (CP): Telephony server and MSG Telephony server ML/MGW ML/MGW Input: Traffic volume (voice and data) subscribers, traffic/subs, mht = mean holding time Traffic distribution Traffic mix Voice Figure A4.1 The studied area Understanding Changing Telecommunications - Building a Successful Telecom Business, by A. Olsson © 2003 Ericsson och Student litteratur. ISBN: 0-470-86851-1 Understanding Changing Telecommunications - Building a Successful Telecom Business Calculate how many interface boards are needed in each multi-service gateway (MSG), based on the interface traffic from connected subscribers and data sources (Task 1). Calculate the MSG processor load (Task 2). Calculate the required processor capacity in the telephony servers (TeSs) (Task 3). Figure A4.1 shows the studied area, which is served by a simplified ATM based MSN, with the subscriber network connections below the 'cloud'. Only ATM and TDM inter- faces are indicated for simplicity, but a typical MSG has a number of other interface possibilities like frame relay, Ethernet and IP/MPLS (multi-protocol label switching). The main components shown are MSGs and telephony servers with mediation logic (ML) and a MGW for switching signaling traffic, transit traffic (break in/brea