3rd March 2006 at 09:15
#32369

Santy

Guest

Erlang B

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 immediately cleared.

Erlang B formula

:Eb(0, t) = 1 \\,

:Eb(r,t) = { {t Eb(r-1,t)} \\over {r+t Eb(r-1,t)} } \\,

where:

Eb is the probability of blocking

r is the number of resources.

t is the number of Erlang offered

Extended Erlang B

This formula is essentially Erlang B, but assumes that a certain percentage of the system, when blocked will immediately represent themselves to the system. This formula can account for this retry percentage.