Analyzing Packet Switching
Packet Switching
Packet switching is a message switching technique in which the data is divided into packets. These packets contain a header that contains the information of the destination. The packets find the route with the help of this information.
The biggest packet-switched network is the internet.
A packet contains header and payload. The header contains the routing information and the payload contains the data to be transferred. The packet switching is also based on the Store and Forward method. Each packet contains the source and destination information so, they can independently travel in the network. The packet belonging to the same file may take different paths depending upon the availability of the path. At the destination, these packets are re-assembled. It the responsibility of the receiver to re-arrange the received packet to the original data.
Example: Suppose the data to be sent is divided into three packets i.e. 1, 2, 3. Now, these packets travel independently in the network. The intermediate nodes forward the nodes according to the availability of the channel. At the receiver side, the order of packets can be different. It is the duty of the receiver to re-arrange the received packets.
The path taken by the packet 1 is S → F → A → D → E →R. Similarly, the path taken by the packet 2 is S → F → A → B → E → R. Similarly, the path taken by the packet 3 is S → F → C → D → E → R.
Advantages of Packet Switching
Packets have fixed sizes, so the switching devices do not require large secondary storage devices. The storage was a problem in message switching which is removed here.
It is more efficient for data transmission as it doesn’t require any dedicated paths.
If the link is busy or not available, the packets can be re-routed. This ensures a reliable connection.
The same channel can be used by many users simultaneously.
With improved protocols, packet switching is used for applications like Skype, WhatsApp, etc.
Analyzing packet switching technique with respect to :
A].Delay:-
Transmission Delay :
Time taken to put a packet onto link. In other words, it is simply time required to put data bits on the wire/communication medium. It depends on length of packet and bandwidth of network.
Propagation delay :
Time taken by the first bit to travel from sender to receiver end of the link. In other words, it is simply the time required for bits to reach the destination from the start point. Factors on which Propagation delay depends are Distance and propagation speed.
Queuing Delay :
Queuing delay is the time a job waits in a queue until it can be executed. It depends on congestion. It is the time difference between when the packet arrived Destination and when the packet data was processed or executed. It may be caused by mainly three reasons i.e. originating switches, intermediate switches or call receiver servicing switches.
Processing Delay :
Processing delay is the time it takes routers to process the packet header. Processing of packets helps in detecting bit-level errors that occur during transmission of a packet to the destination. Processing delays in high-speed routers are typically on the order of microseconds or less.
In simple words, it is just the time taken to process packets.
B].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.
C].Network performance: Packet Switching transmits data across digital networks by breaking it down into blocks or packets for more efficient transfer using various network devices. … The network devices can then route the packets to the destination where the receiving device reassembles them for use.
Packet switching was originally designed to overcome the weakness of circuit switching. The circuit switching is inefficient for sending small messages. Also, the analogous(continuous) circuit makes it prone to noise and errors.
