Module Review

In this module, we explored the “Post Office” of the Internet:

  1. IP Addressing: The logical targeting system using 32-bit values (IPv4) represented in dotted decimal notation.
  2. Subnetting & CIDR: Efficiently dividing networks using masks and slash notation to reduce congestion and improve security.
  3. Routing Protocols: How routers learn the best path using OSPF (Inside an AS) and BGP (Between ASs).
  4. NAT & ICMP: Sharing one public IP via Network Address Translation and troubleshooting using Ping and Traceroute.
  5. IPv6: The 128-bit future of networking that eliminates NAT, simplifies headers, and provides billions of unique addresses.

1. Flash Quiz

1. What is the CIDR notation for the subnet mask 255.255.255.0?

  • /24.

2. Which routing protocol is used to exchange routing information between different Autonomous Systems (AS) on the Internet?

  • BGP (Border Gateway Protocol).

3. What is the primary purpose of NAT (Network Address Translation)?

  • To allow multiple devices on a private network to share a single public IP address.

4. How many bits are in an IPv6 address?

  • 128 bits.

5. What ICMP message is sent back to the sender if a packet’s TTL reaches 0?

  • Time Exceeded.

2. What’s Next?

In the next module, we move to the Transport Layer, where we’ll look at how data is reliably delivered from process to process using TCP and UDP.