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- What is an Erlang?
- How is Erlang B useful for trunk
dimensioning?
- How can I work out how many lines I
need?
- Should I include wrap up time when
using Erlang C?
- How do I work out the Busy Hour
Traffic?
- Is the Call Minutes Calculator
included with Westbay Traffic Calculators?
- Does Westbay Traffic Calculators
have reporting capabilities?
- Do you sell the source code, or a
DLL to which my own programme can connect?
- How accurate are the Erlang
traffic models?
- Why don't you include the Poisson
traffic model?
- Is the product Y2K compliant?
- What traffic levels can the
calculators work up to?
- Which NT Service Packs does the
software work under?
- If I download the software on to my
desktop, will I be able to subsequently transfer the software to my laptop?
Ask us a new question
Purchasing Westbay Traffic
Calculators
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| An Erlang is a unit of traffic measurement. In practice,
it is used to represent one hour of traffic, although strictly speaking, Erlangs are
dimensionless. |
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How is
Erlang B useful for trunk dimensioning?
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| Erlang B is a traffic model which can be used to explore
the relationship between the busy hour traffic offered to a trunk group, the required
grade of service and the number of lines required. As such, it is used for route
dimensioning (determining how many lines are required on a trunk group. |
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How can
I work out how many lines I need?
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| This is a complex issue, and is the subject of a white
paper called Dimensioning
Trunk Groups which is on this Web site. |
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Should I
include wrap-up time with Erlang C?
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| Yes. Wrap up time (or wrap time) is the time an agent remains
unavailable after completing a call. It is usually the time which a call centre agent uses
to complete any administrative tasks relating the the call such as entering an order. As
wrap up time uses an agents time in the same way as actually handling a call, wrap up time
should be included in the average call duration figure. However,
when using Erlang B to estimate the number of lines required into a call centre to deliver
inbound calls, wrap up time should not be included, but the average delay to all calls
should be included as it queuing time occupies a trunk in the same way as
conversation time. |
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How do I
work out the Busy Hour Traffic?
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You need to work out the number of hours traffic offered
to a trunk group during the busiest hour. You could use the following formula:
Busy Hour Traffic = Number of calls * Average call duration (s)
/ 3600
If possible, you should extract these figures from a call logger.
Otherwise, you will need to make reasonable estimates based on your understanding of your
business.
Remember that the busy hour figure should represent the busiest hour you
are ever likely to encounter, so use a month or two's data to work it out. |
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Is the
Call Minutes Calculator included?
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| Yes. It was included from version 2.2 which was
released on 8th. November 1998. |
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Are
there reporting capabilities?
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| Yes. By pressing the Results button, you can see
a list of any calculations you have made during the previous week. You can filter this
list so that the results on view are only for the current session, or any day during the
past week. This calculation history can also be printed. |
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Do you
sell source code or DLLs?
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| No. |
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How
accurate are the Erlang models?
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| They are usually quite accurate and have been used
throughout the industry for decades. But they do make certain assumptions about the nature
of offered traffic which may not necessarily apply in your case. For example, they assume
random (Poisson) arrivals. This is usually reasonable, but sudden peaks of calls resulting
from a radio or television advertisement are not accurately modelled. In these
circumstances, you should use the calculators with caution and common sense. |
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Why
don't you include Poisson?
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| Because we don't think it is very accurate. Poisson (or
Molina) can be used to model situations where there are a high number of retries, that is,
callers who immediately redial because they have encountered blocking. We prefer to use the Extended Erlang B traffic model for this purpose because it
allows you to specify the ratio of blocked calls which will immediately retry. |
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Is
Westbay Traffic Calculators Y2K compliant?
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| Westbay Traffic Calculators does not make any use of absolute dates,
and therefore cannot be effected by the change to a new Millennium. Furthermore, we have
successfully tested the software for the New Year and Leap Day transitions and are
confident that no problems will be experienced if our software is run on Millennium
compliant operating system, firmware and hardware platforms. |
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What
traffic level can the calculator work to?
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| The Erlang B Calculator can work to 25000 Erlangs and
25000 lines. The following table shows the operational limits of
all the calculators:
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Erlang B / Ext. Erlang B |
Erlang C |
Call Minutes |
| Operating system |
Windows 95, 98, ME, NT4, 2000 or Windows XP |
| Traffic model used |
Erlang B / Ext. Erlang B |
Erlang C |
Erlang B |
| Operational limits |
BHT 25000 (max) Erlangs
Blocking 0.001 - 0.500
Lines 25000 (max)
Retries 95% (max) |
ACD Agents 1 - 10000
Calls per hour 1000000 (max)
Duration 10000 (max) seconds |
1 - 30000000 mins. per day
Blocking 0.001 - 0.500
Lines 25000 (max) |
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Which
NT Service packs are supported?
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| Westbay Traffic Calculators has been tested under Windows NT Workstation
4 Service Packs 3 and above and works performs correctly with each of these service packs. |
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Will I be
able to install on my laptop?
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| If you purchase the software when you are using your
desktop computer, then you may transfer the installation file to your laptop computer and
install it there. However, you may not install on both computers if you are only
covered by one single user licence; you will need to buy two licences. |
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Has
this answered your question?
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| If not, then please send us an email. |
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Purchasing
Westbay Traffic Calculators
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| The full working version of the Westbay Traffic Calculators is available
for 139 US Dollars. Usually, the software can be working on
your PC in under 10 minutes!
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