Packet Switching Technique

What is Packet Switching Technique?

Packet switching is the transfer of small pieces of data across various networks. These data chunks or “packets” allow for faster, more efficient data transfer.

Often, when a user sends a file across a network, it gets transferred in smaller data packets, not in one piece. For example, a 3MB file will be divided into packets, each with a packet header that includes the origin IP address, the destination IP address, the number of packets in the entire data file, and the sequence number.

Types of Packet Switching

There are two major types of packet switching:

1.Connectionless Packet Switching. This classic type of packet switching includes multiple packets, each individually routed. This means each packet contains complete routing information — but it also means different paths of transmission and out-of-order delivery are possible, depending on the fluctuating loads on the network’s nodes (adapters, switches and routers) at the moment. This kind of packet switching is sometimes called datagram switching.

2.Connection-Oriented Packet Switching. In connection-oriented packet switching, also called virtual circuit switching or circuit switching, data packets are first assembled and then numbered. They then travel across a predefined route, sequentially. Address information is not needed in circuit switching, because all packets are sent in sequence.

Now lets Analyze packet switching technique with respect to :

Delay :

As there is no dedicated path and there is presence of multiple nodes on the path ,some amount of time is required to process the datagram at each node .If the traffic is more the the time required is more and till then the datagram is in the queue. Packet can travel along different paths so time required to reach the destination for each packet is different .If the distance between source and destination to large and also the propagation delay is to large then there is some delay in the network called propagation delay.If the transforming rate of the router present in the rout is greater than the receiving rate of the next router then that router have the make the packet to wait until the current packet is processed and transferred. This type of delay is called queuing delay. Sometimes the router takes time to process the data over network and this type of delay is called processing delay. In simple words, it is just the time taken to process packets. As the movement of packets is not synchronous in this switching, it may not be suitable in communication applications like voice calls; while circuit switching is highly suitable for voice calls

Reliability :

The packet switching process is reliable in that the destination can identify any missing packets. However, circuit switched networks deliver packets in order along the same route and are therefore less likely to experience missing packets in the first place.

Data transmission :

In this switching technique, the data transmission begins as soon as the data is transmitted from the sender and placed over the network. Here no particular path is assigned for the packets to follow. They can go through any path that is available between to reach to the destination. Now to assemble all the packets in a sequence at receiving end the sender’s OS give the sequence number to each packet in order and at receiver end all these packets are arranged in the same sequence.

Network Performance :

Packet Switching uses lesser bandwidth as packets are quickly routed towards the destination; circuit switching should have dedicated bandwidth. The channel in this switching is available for other transmissions as soon as packets are routed; circuit switching occupies the channel till the voice communication is completed.In packet switching, network performance totally depends on the transmitting and receiving speed of the router present between the source and destination. If the bandwidth of network is sufficient then the whole process works smoothly

Error Handling :

Packets contain checksum, parity bits or cyclic redundancy checks. These each detect errors that may occur during transmission.A preliminary calculation is performed before the packet is sent, at the transmitter. Once the packet is received, the checksum is recalculated and compared with the first calculation that is contained in the packet. If any discrepancies are noticed the packet can be corrected or discarded. Any discarded information is known as packet loss and will be dealt with by the network protocol.

Implementation :

Packet switching is one such technology used nowadays on data networks like the Internet LAN, WAN. The development of Voice over Internet Protocol (VoIP), enabled packet switching to easily transmit data and voice traffic. This allowed businesses to experience huge benefits in terms of cost, efficiency, and scalability .It is well suited to data transmission, as it allows networks to adapt to changing conditions quickly. For example, if one of the network’s router fails, packet can be automatically re-routed to avoid that device.