THEORY EXAMINATION (SEM–VIII) 2016-17 ELECTRONIC SWITCHING

SECTION – A

Attempt all parts (Short Answer Type)

Automatic exchange is a telephone switching system where calls are connected automatically without human operators, while manual exchange requires operators to connect calls manually.

Voice traffic refers to continuous communication signals such as phone calls, while data traffic consists of digital information transmitted in packets.

In-band signalling uses the same channel for both voice and control signals, while out-band signalling uses a separate channel for control information.

HDLC frame structure includes flag fields, address field, control field, information field, and frame check sequence.

A two-motion selector is a switching device used in telephone exchanges that can move in both horizontal and vertical directions to connect calls.

Grade of Service (GOS) is a measure of the probability that a call will be blocked or delayed due to network congestion.

Average occupancy refers to the proportion of time a switching system is busy handling traffic.

Segregation in switching refers to separating different types of traffic or services within a network.

Blocking probability is the likelihood that a call cannot be connected due to insufficient resources.

Cross points are switching elements in a network that connect input lines to output lines in non-blocking switching structures.

Questions (Section A)

What is automatic exchange?

Define in-band signalling.

What is GOS?

Define blocking probability.

What is a two-motion selector?

SECTION – B

Attempt any five (Long Answer Type)

Blocking probability in switching networks can be calculated using Lee graph, which represents connections between inputs and outputs.

Birth-death process describes traffic flow in telecommunication systems where calls arrive and depart over time. It helps analyze congestion and network performance.

Common channel signalling uses a separate channel for control signals. SS7 architecture supports high-speed and reliable signalling in telecommunication networks.

Erlang B formula calculates the probability of call blocking in systems without waiting queues, while Erlang C considers waiting time for calls.

ATM switches transfer data using fixed-size cells. VPI and VCI are identifiers used to route these cells through networks.

Stored Program Control (SPC) can be centralized or distributed, depending on how control functions are managed in switching systems.

Software in SPC systems includes operating software, application software, and maintenance software.

Memory-space switches use memory to temporarily store and route data, while banyan networks provide efficient switching paths.

Questions (Section B)

What is blocking probability?

Explain birth-death process.

What is SS7 architecture?

Compare Erlang B and Erlang C formulas.

Explain ATM switch operation.

SECTION – C

Attempt any two (Detailed Explanation)

Reed-relay switches use magnetic relays for switching operations in telecommunication systems. General trunking diagrams show how communication lines connect between exchanges.

Markov process describes systems where future states depend only on current states. It is used in traffic analysis of telephone networks.

X.25 is a packet-switching protocol, while frame relay provides faster data transmission with less error checking. SS6 is a signalling system used for communication control.

Questions (Section C)

What is reed-relay switch?

Explain Markov process.

What is frame relay?