42 Chapter 2 System telephony networking overviewNN40020-603NN40020-603Figure 5 PRI networking using Call-by-Call ServicesTo reduce long distance costs, and to allow for a coordinated dialing plan between the offices,private lines are used to handle inter-office traffic.If call-by-call services were not used, each BCM system might have to be equipped with thefollowing trunks:• 12 T1 DID lines needed to handle peak incoming call traffic.• eight T1 E&M lines needed to handle inter-office calls.• eight lines needed to handle outgoing public callsPRI SL-1/Q.Sig/DPNSS and VoIP trunk networkingYou can use PRI SL-1 trunks and VoIP trunks to create private networks between BCM systems orbetween BCM systems and larger call servers such as Meridian 1, Succession 1000/M, DMS-100/250 and CSE.ETSI-QSIG and DPNSS private networking is configured very similarly, although networkfeatures may be supported slightly differently due to local line and network requirements.If the MCDN protocol is added to this type of private network, the network provides additionalnetwork management features, as well as allowing centralized voice mail features to be availableto all nodes on the network.The following topics describe the different aspects of SL-1 and MCDN private networking.• “System dialing plans” on page 43• “Creating tandem private networks” on page 43Network # 2221Received # 2221Internal # 2221DID # 763-2221Network # 6221Received # 6221Internal # 6221DID # 562-6221Toronto office New York officeTIE ConnectionPublic NetworkPRI PRIBCMCentralOfficeCentralOfficeBCM
