NEC UNIVERGE NEAX 2000 IPS - Manual (Page 56)

Chapter 3 System Highlights
Page 3- 8 UNIVERGE NEAX 2000 IPS Request For Proposal (RFP) Reference Guide
Issue 6
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 U NIVERGE NEAX 2000 IPS is shown below.
Number of PIM’s 1PIM 2PIM 3PIM 4PIM 5PIM 6PIM 7PIM 8PIM
Business or
Hotel/Motel
without ACD/OAI
Max. 2500 BHCA
(No FP)
Max. 5000 BHCA
(One FP)
Max. 7500 BHCA
(Two FPs)
Max. 8000 BHCA
(Three FPs)
Business or
Hotel/Motel with
ACD/OAI
Max. 2000 BHCA
(No FP)
Max. 4000 BHCA
(One FP)
Max. 5000 BHCA
(Two FPs)
Max. 5500 BHCA
(Three FPs)