Calculations 381Procedure 53 "Calculating Branch Office traffic, and LAN/WAN bandwidthwithout local messaging (CallPilot) capabil" (page 381) covers only simpleCallPilot voice messaging traffic for a LAN/WAN bandwidth calculation.The engineering requirement for Multimedia Processing Units (MPU),such as CallPilot, depends on traffic type (for example, voice, fax, andspeech-recognition) and service type (for example, enterprise networking,network message service). The MPU requirement calculations, whichrequire several traffic tables to cover various Grade of Service practices,do not impact LAN/WAN calculation directly and are not presented here.Refer to the CallPilot Planning and Engineering Guide (555-7101-101)formore information.To leave a voice message for a user in a Branch Office, route the incomingcall to the main office. Similarly, when a user retrieves the voicemailmessage, the connection takes place over the LAN/WAN to the mainoffice. To leave or retrieve a message, the connection requires LAN/WANbandwidth.Procedure 53Calculating Branch Office traffic, and LAN/WANbandwidth without local messaging(CallPilot) capabilityStep ActionThe following are default values of parameters to estimate CallPilot traffic.Specific traffic information about a site should be used if known.1 Calculate Messaging traffic:Average holding time of a voice message: 40 seconds (defaultrecommended by the CallPilot NTP)Voice Messaging Traffic (VMT) = Voice Messaging Calls x 40/100CCS = Voice Messaging Calls x 40/3600 erlangsIf you have no information about messaging calls (leaving orretrieving a message), use the following approximation:VMT = 10% x Total MG 1000B traffic in CCS = 10% xTotal MG 1000B CCS traffic/36 (Erlangs)2 Calculate LAN/WAN bandwidth:For a G.729A/30 ms codec:LAN/WAN kbps = VMT (erlangs) x 9 kbpsFor a G.711/30 ms codec:Nortel Communication Server 1000Branch Office Installation and CommissioningNN43001-314 01.02 StandardRelease 5.0 20 June 2007Copyright © 2007, Nortel Networks.
