Teletraffic theory Examination test.

Determine the required number of lines in a fully accessible single-link operation, provided that the flow parameter is λ = 180 calls / h and the average service time per call is h = 60 s. The losses should not exceed 2.0%.

2.0% = 0.02

180 * 60/3600 = 3

0,0081

Answers 8

The PD bundle of 12 lines receives the simplest call flow with the parameter

λ = 320 call / hour. The service time is distributed according to the exponential law with an average value of h = 90s. Determine the proportion of calls delayed beyond the allowable time P (γ> t), td = 0.5 cu.

320 * 90/3600 = 8

Answers 0,15

What is the formula used for?

Answers

1. to determine the average waiting time for all calls

2. to determine the average queue length

3. to determine the share of call waiting

What call flow is called primitive

Answers

1. non-stationary ordinary stream with aftereffect

2. stationary ordinary stream without aftereffect

3. stationary ordinary stream with aftereffect

4. random ordinary call flow parameter, which directly proportional to the number of free sources of load at a given time

What does the concept of "stream with aftereffect"

Answers

1. unchanged probability characteristics of the flow in time

2. dependence of probabilistic characteristics of the call flow from previous events

3. independence of probabilistic characteristics of the call flow from previous events

What indicators are used to quantify the quality of service systems with waiting?

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1. probability of losing a call P = Ev (y)

2. probability Pt (t)

3. probability of call delay P (γ> 0)

Choose a mathematical model of the system with the expectation that serves the simplest call flow

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one.

2

What the formula shows

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1. probability of call delay in the system with repeated calls

2. the probability of losing a call to the system with obvious losses

3. probability of call delay in the system with waiting

What is called a wait system?

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1. a system in which part of the incoming calls in the absence of free exits is queued for waiting

2. a system in which incoming calls in the absence of free exits are queued for waiting

3. the system in which incoming calls are queued for waiting

Occupation is

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1. source request to establish connection

2. any use of the instrument or line to establish a connection

3. form of information representation, having signs of beginning and end

What does record mean?

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1. scheme that receives a call flow with an arbitrary function of the distribution of the intervals between calls and the exponential distribution function of the service

2. a circuit having V outlets, to which a call flow arrives with an exponential function of the distribution of gaps between calls and an exponential function of the distribution of service duration

3. a circuit with V waiting places, to which a call flow arrives with an exponential function of the distribution of gaps between calls and an exponential function of the distribution of service duration

In which units the intensity of the telephone load is measured

Answers

1. hour-lesson

2. 1 Earl

3. hour-lesson per minute

4. 1 ppm

The requirement of a source to establish a connection that has arrived in a communication network, a switching system, to the input of a search stage, to a control device for the purpose of transmitting or servicing a message is

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1. challenge

2. message

3. occupation

What is CHNN

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1. busy hour

2. the number showing the lowest load

3. number showing the greatest load

What is the formula below -

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1. to describe call service processes

2. to describe the scheme of the information distribution system

3. for compact recording of mathematical models

Who is the founder of Teletraffic Theory

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1. G. O, Dell

2. T. Engset

3. A.Erlang

What allows to determine the formula of the first Erlang distribution

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1. i –th state of the switching system, which receives the simplest call flow

2. probability of i-calls arriving at the switching system

3. the probability of loss of calls when the switching system is serviced by a simple call flow

Determine at which value of k the highest probability value takes place. if λt = 9

Answers

1. k = 7

2. k = 8 and k = 9

3. k = 9