Why Do We Need IP Addresses? - Computerphile

TL;DR

MAC addresses and IP addresses serve different purposes in networking, with MAC addresses identifying network interfaces and IP addresses enabling interconnection between networks.

Transcript

we had this idea of a machine having or a network card or a wifi card having a "mac" address which I understand to be a unique address to that dev... not necessarily that device but certainly to that network interface (that's probably the best word for it is it?) So, the question is why do we need IP addresses if we've got mac addresses? It's an in... Read More

Key Insights

• ❓ MAC addresses are used to identify devices on a local network, while IP addresses enable communication between networks.
• 💄 MAC addresses can be changed, making them less reliable for identification purposes.
• 💄 IP addresses have more structure and scalability compared to MAC addresses, making them more suitable for routing data across the internet.
• 🔥 MAC addresses are burnt into hardware in physical devices, while IP addresses can be assigned dynamically through software.
• 🚫 IP addresses allow for prefix matching, enabling more efficient routing by representing blocks of addresses with a single entry.
• 💁 The structure of IP addresses makes it possible to compress the entries in routing tables, reducing the amount of information that needs to be stored and processed.
• 🥺 Mistakes in routing configurations can lead to unnecessary traffic routing and bottlenecks.

Questions & Answers

Q: Why do we need IP addresses if we already have MAC addresses?

MAC addresses and IP addresses serve different purposes. MAC addresses are used to identify devices on a local network, while IP addresses enable communication between networks. MAC addresses have limited scalability and lack structure, making them impractical for routing data across the internet.

Q: Can MAC addresses be changed?

Yes, MAC addresses can be changed, especially on network cards, particularly in WiFi networks. This ability to change MAC addresses has made spoofing on WiFi networks relatively easy.

Q: How are MAC addresses and IP addresses structured differently?

MAC addresses consist of six bytes and have a specific structure indicating the manufacturer and the station on the network. In contrast, IP addresses consist of four bytes in hexadecimal format and can be represented as a dotted quad notation, allowing for more efficient routing.

Q: Why do IP addresses allow for more efficient routing compared to MAC addresses?

IP addresses have more structure embedded in them, allowing for prefix matching. This means that blocks of IP addresses can be represented by a single entry in a routing table, reducing the number of entries needed for efficient routing.

Summary & Key Takeaways

• MAC addresses are unique addresses assigned to network interfaces and are primarily used to identify devices on a local network.

• IP addresses, on the other hand, enable communication between networks and are used to route data packets across the internet.

• MAC addresses are limited in their scalability and lack structure, while IP addresses provide more structure and scalability through prefix matching.