Author: Neftaly Malatjie

Question 3 (SO 2, AC 4)

Describe the network configurations process and identify potential installation issues.                        (10 marks)

Question 2 (SO 3, AC 3)

You are required to interview any computer technician who specializes in computer networking. The purpose of the interview is to identify WAN management issues. Present your answers in a report format.

Question 1 (SO 2, AC 4)

Research and present in a report format, the standards for industry network architectures in South Africa.           

Circuit switching is a switching method in which a dedicated communication path in physical form between two stations within a network is established, maintained and terminated for each communication session. It has basically three phases as circuit establishment, data transfer and circuit disconnect.

Once the connection is established, the data transfer is transparent. The main feature of such a connection is that it provides a fixed data rate channel and both subscribers must operate at this rate, It is considered inefficient compared to packet switching because channel capacity is completely dedicated for duration of connection. If there is no data at any moment of time, channel capacity goes wasted. Moreover, setting up of connection takes time.

Circuit switching has two types of transmissions.

• Datagram transmissions –Datagram transmissions have individually addressed frames.
• Data-stream transmissions– Data-stream transmissions have a stream of data for which address checking occurs only once. The routing in circuit switching may have either static routing or dynamic routing. In case of static routing, this methodology uses the same approach all the time while dynamic routing allows alternate routing depending on traffic.

 The Key Point of Circuit Switching are.

1. It is the simplest method of data communication in which a dedicated physical connection or path is established between the sending and receiving device.
2. In circuit switched networks, a set of switches are connected by physical links. A connection between two stations is a dedicated path made of one or more links.
3. Figure shows a circuit switched network in whichcomputer A, B and C are connected to computer D, E, F and G via four switches. If these computers are to be connected with a point-to-point connections, 12 dedicated lines are required which will incur high line cost.
4. The four switches connecting these computers thus provide dedicated links by reducing the line cost. Here I, II, III and IV are the circuit switches or nodes. Nodes I, III, IV are connected to computers while II is only routing node.

1. In circuit switching the routing decision is made when path is set up across the network. After the link has been set between the sender and receiver, theinformation is forwarded continuously over the link.
2. The dedicated path established between the sender and the receiver is maintained for entire duration of conversation.
3. This link or path is released only when data transmission between sender and receiver is over.
4. Circuit switching takes place at the physical layer.
5. Before starting communication, the stations must make a reservation of resources to be used during the communication. These resources can be switch buffers, switch processing time, switch input/output ports. These resources remain dedicated during the entire duration of data transfer.

1. 10 Data transferredbetween the two stations are not packetized (i.e. in form of packets). The data are a continuous flow· sent by the source station and received by the destination station and there may be periods of silence.
   6. There isno addressing involved in data transfer. The switches route the data based on their occupied band (FDM) or time slot (TDM). However, there is end-to-end addressing used during set up phase.
   7. In telephone systems circuit switching is used.
   8. The communication in a circuit switched network takes place in three phases:

• Circuit establishment or setup phase.
• Data transfer phase.
• Circuit disconnects or tears down phase.

Addressing modes are an aspect of the instruction set architecture in most central processing unit (CPU) designs. The various addressing modes that are defined in a given instruction set architecture define how machine language instructions in that architecture identify the operand(s) of each instruction. An addressing mode specifies how to calculate the effective memory address of an operand by using information held in registers and/or constants contained within a machine instruction or elsewhere.

The following are features of node addressing methods;