IP addressing, media, packet switching and routing
Follow packets from source addressing through a transmission medium and routing decisions to the destination.
Address → medium → packet → route
- describe IPv4/IPv6, public/private and static/dynamic addressing plus NAT;
- compare fibre optic, twisted pair and wireless using all required factors;
- explain packet segmentation, headers, independent transmission and reassembly plus switch/router roles;
- explain static and dynamic routing using configuration, maintenance, complexity, resource usage, convergence, scalability and network size.
Rapid Recall Deck
Attempt each card first. If a term is new, flip and study it, then answer it again without looking. Mark only secure recall as “Know it”.
IP addressing choices solve different management problems
Classify the address
A school printer must always be found at the same internal address, while student laptops receive an address automatically when they join Wi-Fi. Describe the likely addressing choice for each.
The printer can use a private static internal address so clients/admin systems can find it consistently. Student laptops can use private dynamic addresses assigned by DHCP because devices join/leave and do not need one permanent address.
IPv4 vs IPv6
Describe the main addressing reason IPv6 was introduced and one visible difference in representation.
IPv6 provides a vastly larger address space than IPv4, reducing pressure caused by limited IPv4 addresses. IPv4 is commonly written as four decimal octets, while IPv6 uses a longer hexadecimal colon-separated representation.
Private addressing becomes externally usable through translation
NAT path
Laptop: private IP 192.168.x.x
↓
Router / NAT
↓
Public internet using public address information
↓
Remote server
Explain how NAT helps a private network communicate with the public internet and why it reduces public-address demand.
NAT translates internal private source/address information into public addressing used on the internet and tracks the translation so returning traffic can be delivered to the correct internal device. Multiple private devices can therefore share limited public IPv4 addressing rather than each requiring its own public address.
Use all eight required factors when the question is broad
Compare transmission media
A new campus backbone must carry high-volume traffic between buildings, while classroom devices need flexible local access.
Fibre optic: very high bandwidth/long range, low electromagnetic interference and good security against casual interception, but installation/equipment cost and complexity can be higher. Twisted pair: cheaper/easier to install for local wired links, reliable over normal LAN distances, but lower range/bandwidth and more interference/attenuation constraints than fibre. Wireless: flexible and avoids cabling to each client, but shared medium/interference, range, security and environmental reliability can reduce performance. Fibre is strong for the backbone; wireless can complement it for mobile/classroom access.
Packets can travel independently but the message must be reconstructed
Original data
↓ split
[P1 header|data] [P2 header|data] [P3 header|data]
↘ ↓ ↙
independent forwarding routes
↓
destination
↓
reassemblyExplain packet switching
Explain packet switching from sender to destination: how the original data is split, what routing/control information packets carry, how switches and routers forward them, and how the destination reconstructs the data.
The sender divides data into packets and attaches header/control information used for delivery/routing. Packets can be forwarded independently and may take different paths. Switches move traffic across local network segments while routers forward packets between networks using routing information. At the destination, control/sequence information allows packets to be checked and reassembled into the original data.
Routing strategy depends on change rate and network scale
Static vs dynamic routing
Compare routing for (A) a tiny stable network with three routers and rare changes and (B) a large network that changes frequently.
Static routing requires manual configuration/maintenance, uses little routing-protocol resource and is predictable, so it can suit a small stable network; however changes must be updated manually and scalability is poor. Dynamic routing uses resources/logic to exchange/update route information and must converge after changes, but it adapts more automatically and scales better to large/changing networks. No specific routing protocol is required for this explanation.
Local forwarding and route convergence are separate ideas
Switch decision
A packet/frame arrives at a switch on a LAN. Describe the switch's role without claiming that it performs the entire internet route.
The switch forwards local traffic toward the appropriate port/interface within the LAN. It helps the packet/frame reach the router or local destination, while inter-network path selection is the router's role.
Convergence
What does convergence mean in the context of dynamic routing after a network change?
Convergence is the process/time for routing information across participating routers to become updated and consistent enough that routes reflect the changed network topology.
The specimen tests function + mechanism + comparison
Specimen-calibrated mini-set
1. Compare fibre-optic cable and twisted-pair cable for a high-bandwidth long-distance link.
2. Explain how a switch contributes to packet transmission within a LAN.
3. Describe the role of NAT when private devices access the public internet.
- Fibre generally provides higher bandwidth/longer range, lower electromagnetic interference and lower attenuation, but tends to cost more and be harder to install; twisted pair is cheaper/easier for local links but has shorter range/lower bandwidth and greater interference/attenuation limitations.
- The switch examines local forwarding information and sends traffic toward the appropriate LAN port/interface, reducing unnecessary local transmission compared with sending it everywhere.
- NAT translates private internal addressing to public addressing for external communication and tracks translations for return traffic, allowing many private devices to share limited public address resources.
Finish the learning cycle
IA — main task
Continue IA Criterion E/final-submission work according to your schedule. Link evaluation statements directly to the agreed success criteria.
Paper 1 — short practice
Recreate the IP-addressing map, the eight-factor media comparison, the packet-switching sequence and the seven-factor static-vs-dynamic routing comparison.