IP addresses are 32 bits (4 bytes) split into 4 chunks. Obviously is an incredibly large address space so we compress the table using IP prefixes.

It is generally recognized that the current approach of using the IP address as a locator and as an identifier was a poor design choice. (Clark, 2018, “Designing an Internet”)


Special Addresses

  1. First address (generally all 0s): network itself, or not assigned
  2. Last address (generally all 1s): broadcast

CIDR Notation

IP/# where # is the number of bits in the network ID

e.g. means first 8 bits are network ID, and 18.x.x.x is the space of all possible addresses ()

By default, routers will take the most specific one (longest network ID).

To prevent loops, we set a TTL (time-to-live) for packets to expire after a certain time.