This key facts covers How Packet Switching Works within Packet Switching for GCSE Computer Science. Revise Packet Switching in 3.5 Fundamentals of Computer Networks for GCSE Computer Science with 15 exam-style questions and 18 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 5 of 12 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
How Packet Switching Works
Step-by-Step Process:
1. Data Division:
- Large message/file broken into small packets (e.g., 1MB file → 700 packets of 1500 bytes)
- Each packet numbered for reassembly
2. Adding Headers:
- Each packet gets header with source/destination IP, packet number
- Trailer added with error-checking information
3. Transmission:
- Packets sent across network independently
- Each packet can take different route through routers
- Routers forward packets based on current network conditions
4. Routing:
- Routers read destination IP in header
- Choose best available route (fastest, least congested)
- Different packets may take different paths
5. Arrival:
- Packets arrive at destination (possibly out of order)
- Error checking performed using trailer
- Damaged packets reported, retransmission requested
6. Reassembly:
- Packets sorted using sequence numbers
- Reassembled into original message/file
- Complete data delivered to application
Practice questions for Packet Switching
Which of the following best describes packet switching?
Explain why packets from the same file can travel by different routes through a network. [2 marks]