PACKET SWITCHING AND CIRCUIT SWITCHING AS PART OF NETWORK AND HARDWARE

LESSON OBJECTIVES explain the difference between packet switching and circuit switching explain the format of an IP address and how an IP address is associated with a device on a network detect network faults with the help of different utilities

TASK. Create a presentation in pairs to explain one of the following: 1.The steps that take place in Packet Switching. 2.The difference between packet switching and circuit switching. The benefits and drawbacks of each system. 3.Subnet masks and IP Address Formats.

PACKET SWITCHING Packet switching is a digital networking communications method that groups all transmitted data into suitably sized blocks, called packets, which are transmitted via a medium that may be shared by multiple simultaneous communication sessions. Packet switching increases network efficiency, robustness and enables technological convergence of many applications operating on the same network.

PACKET SWITCHING STEPS Data split into chunks (packets) Each packet has a from address, to address and payload (data chunk) If data requires multiple chunks then the order of each packet is noted Packets sent onto the network, moving from router to router taking different paths (set by the router). Each packet's journey time can therefore differ. Once packets arrive they are re-ordered Message sent from recipient to sender indicating that the message has been received If no confirmation message, sender transmits data again

EXAMPLE: THE PING COMMAND To see the time it takes to send a message using packet switching you can use the ping command to time how long it takes to send data to another device

EXAMPLE: THE TRACE COMMAND The tracert command is used to map the route from one machine to another on the internet showing all the intermediate nodes, in this case, the message took ten step Different commands used on different operating systems: Windows - tracert Linux - tracepath or traceroute Mac - traceroute

CIRCUIT SWITCHING Circuit switching is a methodology of implementing a telecommunications network in which two network nodes establish a dedicated communications channel (circuit) through the network before the nodes may communicate. The circuit guarantees the full bandwidth of the channel and remains connected for the duration of the communication session. The circuit functions as if the nodes were physically connected as with an electrical circuit.

TASK In groups list the benefits and drawbacks of each. Discuss group findings to the whole class.

IP ADDRESS FORMATS Originally IP addresses were divided into five classes as shown below. Classes A, B and C are the most important: the initial bits determine which class an address belongs to, and the classes differ in how much of the address is taken up with the network address and how much with the host address.

NETWORK ADDRESS TRANSLATION Network Address Translation is a technique which allows for the composition of a network to be completely hidden from the outside world, with the entire network identified by a single IP address. Within the network, hosts and routers have addresses which are unique to that network, typically taked from the ranges designated as "private"

NETWORK FAULTS

TASK 2 Group is given a range of problems with a network; they can only see the symptoms. How can they work out what the problem is?