 |
Business | Industries | Finance | Tax |
| Index: > A B C D E F G H I J K L M N O P Q R S T U V W X Y Z |
|
|||||
| First Prev [ 1 2 ] Next Last |
In the traffic calculation, one Erlang implies a single resource in continuous use (or two channels at fifty percent use, and so on, pro rata ). For example, if a bank has two tellers and during the busiest hour of the day they are both busy the whole time, that would represent two erlang of traffic.
Typically erlang might be used to determine if a system is over- or under- provisioned (has too many or too few allocated resources).
It might be used to measure traffic on a T-1 or E-1 line, to determine how many voice lines are in use at the busiest hour of the time period being examined; for 24 channels, if only 12 are ever in use, the other 12 might be made available as data channels.
Traffic calculations measured in erlang can also be used to calculate grade of serviceIn telecommunication, the term grade of service (GOS) has the following meanings: #The probability of a call being blocked or delayed for more than a specified interval, expressed as a decimal fraction. This may be applied to the busy hour or to some othe (GoS) or quality of serviceIn the fields of telecommunications and computer networking, the traffic engineering term Quality of Service QoS can mean two related but distinct things. In circuit-switched networks it refers to the probability of being able to initiate a call to anothe (QoS). The GoS or QoS of a particular resource is the probability of traffic being offered to a resource meeting a condition where it cannot be served now. GOS is calculated from the perspective of the resource and not the perspective of the request.
There are a range of different Erlang formulae, including Erlang B, Extended Erlang B, Erlang C and a related Engset formula.
Calculates traffic in loss systems. If a request is not served when it is offered to the resource then it is lost. These systems can be considered as non-queued. This model assumes the blocked traffic is immediatly cleared.
where:
This formula is essentially Erlang B, but assumes that a certain percentage of the system, when blocked will immediatly represent themselves to the system. This formula can account for this retry percentage.
This formula calculates the capacity necessary to queue traffic. This model assumes that all blocked calls stay in the system until they can be handled. This model can be applied to the design of call center staffing arrangements where, if calls cannot be immediately answered, they enter a queue. This is often used to calculate the number of agents or customer service representatives needed to staff a call center.
where:
The Engset formula (named after Tore Olaus Engset (1865-1943)) is also related but deals with a small population of finite sources rather than the large population of infinite sources that Erlang assumes.
| Politics | Business | Finance |
 |
 |
 |
|