IP Addressing (A2.3 Data transmission)

I. Types of IP

Not necessarily mutually exclusive

Public (Types of IP)

Accessible over the Internet

Private (Types of IP)

For devices within private networks

Static (Types of IP)

Manually and permanently assigned to device (same every time device connects to network) 

• Essential for servers (so clients know where to locate on network)

Dynamic (Types of IP)

Automatically and temporarily leased/assigned

• Process overseen by DHCP server

• Efficiently uses number of limited available IP addresses (IPv4) where devices frequently dis/connect = v overhead

• Used for clients (come and go)

II. IP versions

Most commonly used IP versions

IPv4 (IP versions)

4-byte or 32-bit address space

• Most common way of assigning IP

• Dotted-decimal notation (usually displayed as four numbers, each within range of byte or 0-255, separated by dots)

• Limited to 2³² possible addresses (~4.3B nodes on network)

• Complex header format (14 fields)

• Optional IPsec support (protocol facilitating encryption)

IPv6 (IP versions)

128-bit address space

• Hexadecimal notation with colons

• Designed to deal with rising issue of IPv4 addresses running out

• 2^128 or ~340 undecillion unique addresses

• Simplified header format (8 fixed fields)

• Mandatory IPsec support

III. Network Address Translation (NAT)

Process that translates private IP to public IP and vice versa

• = multiple devices share single public IP address

• Crucial for internet (dependent on IPv4 address)

• Hiding internal IP addresses from external network = ^ security for home and small office networks