Packets and Reassembly

Part of: Computer Systems & Networks

Breaking Data into Packets. When you send a file over the internet, it is not sent as one big chunk. It is split into small pieces called packets . Each packet carries: - A piece of the data (the payload) - The destination address - A sequence number so the pieces can be reassembled in order This is called packet switching . Packets from the same message can take different paths across the network and still arrive correctly. Why Packets Can Arrive Out of Order. Because packets travel independently, packet 5 might arrive before packet 3. The receiving computer uses the sequence numbers to reassemble them correctly. If a packet is lost, the protocol can request that it be resent. Reassembling a Message. The receiver collects all packets, sorts them by sequence number, then joins their payloads back into the original message: Why Packet Switching Is Efficient. - Sharing : many messages share the same links instead of reserving a private circuit. - Resilience : if one path is congested, individual packets can take another route. - Granularity : only the lost packets must be resent, not the whole file. What usually goes wrong. What you see What caused it How to fix it --- --- --- The wo

Challenge: Reassemble a Packetized Message