NEC 2000 IPS manual System Traffic, Traffic Load, Bhca Busy Hour Call Attempts

Chapter 3 System Highlights

System Traffic

In regards to the traffic capacity of electronic PABX, two kinds of descriptions are usually employed. One is Busy Hour Call Attempts (BHCA), which relates to the ability of the Central Processor Unit (CPU). Another is the traffic handling capacity per line that relates to the handling capacity of each station. This technical information herein offers the traffic data for both cases.

Traffic Load

Traffic load is expressed as the quantity of traffic during the busy hour, the busiest one-hour period of the day for traffic. Traffic can be measured in minutes, hours, hundreds of call seconds (CCS), or Erlangs.

CCS– one CCS is equal to 100 seconds of telephone time, or 1/36 Erlang.

Erlang– one Erlang is equal to one hour of telephone time or 36 CCS.

CCS units are convenient when traffic is measured in small increments. For telephone traffic, a typical business generates about 6 CCS per telephone during the busy hour (1/6 Erlang).

Busy Hour

The hour during the day when traffic is highest is called the busy hour. Since this is the period when users are most likely to encounter blockage, the traffic load during the busy hour is the load you need to plan for. Traffic tables show the amount of traffic that can be handled during the busy hour. Within the busy hour, peaks will occur when blockage will be higher than the design objectives. It's not economical, however, to design a network to handle absolute peaks. Most networks are designed to cause some traffic to be blocked or overflow to other services.

One way to establish the load during the busy hour is to schedule traffic studies for a week when you know the load is high. Or, you can use tables developed by traffic engineers to estimate the busy hour load.

BHCA (Busy Hour Call Attempts)

BHCA of the UNIVERGE NEAX 2000 IPS is shown below.

Number of PIM’s	1PIM	2PIM	3PIM	4PIM	5PIM	6PIM	7PIM	8PIM
Business or
Hotel/Motel	Max. 2500 BHCA		Max. 5000 BHCA		Max. 7500 BHCA		Max. 8000 BHCA
without ACD/OAI
	(No FP)		(One FP)		(Two FPs)		(Three FPs)
Business or
Hotel/Motel with	Max. 2000 BHCA		Max. 4000 BHCA		Max. 5000 BHCA		Max. 5500 BHCA
ACD/OAI
	(No FP)		(One FP)		(Two FPs)		(Three FPs)

Page 3- 8	UNIVERGE NEAX 2000 IPS Request For Proposal (RFP) Reference Guide
	Issue 6