Answer to Question #320246 in Computer Networks for Bismark Akyen

Question

1.      Suppose end system A wants to send a large file to end system B. At a very high level, describe how end system A creates packets from the file. When one of these packets arrives to a router, what information in the packet does the router use to determine the link onto which the packet is forwarded? Why is packet switching in the Internet analogous to driving from one city to another and asking directions along the way?

Answer 1

When an end system A wants to send a large file to end system B, it first divides the file into chunks. It then assigns a header to each chunk creating a packet. Each packet contains the address of the destination in its header. Thus, multiple packets are generated from the file.

When a packet reaches the packet switch, the switch uses the destination address that is in the header to know on to which link the packet has to be forwarded.

Each packet contains the address of the destination in its header. On reaching packet, the address of the destination on the header of the packet specifies which outgoing link it should be forwarded. This is analogous to asking which road to take.

Suppose system A want to sent packet to system B steps involved

in this process are given below

1. System A first breaks large file into small pieces generally known as chunks.

2. It adds separate headers for each chunks so that each chunk appears like separate packet.

3. Header file in chunks contain IP address of receiver here system B.

4. Switch system uses IP present in header to determine link to destination.

When we travel from one city to another and we don’t know

the path then we ask for path and go on that which is same like

packet switching process.