Overview
This lecture introduces the structure, assignment, and management of IP addresses, highlighting their notation, distribution, and dynamic versus static allocation.
Structure of IP Addresses
- IP addresses are 32 bits long and split into four octets.
- Each octet is 8 bits, representing numbers from 0 to 255.
- IP addresses are usually written in dotted decimal notation, e.g., 12.34.56.78.
- IP addresses with octets above 255 (e.g., 123.456.789.100) are invalid.
Distribution and Hierarchy of IP Addresses
- IP addresses are allocated in large blocks to organizations, not to hardware vendors.
- The assignment system is hierarchical and simplifies data management compared to physical addresses.
- Example: IBM owns all IPs with 9 as the first octet and routes packets addressed to those IPs internally.
IP Addresses vs. Device Addresses
- IP addresses are assigned to networks, not directly to devices.
- Devices retain their MAC address, but their IP address changes depending on the network they join.
- Each local network (LAN) assigns IP addresses to connecting devices.
Dynamic and Static IP Addresses
- Most devices receive IP addresses automatically via Dynamic Host Configuration Protocol (DHCP), resulting in dynamic IP addresses.
- Static IP addresses are manually configured and typically used for servers and network devices.
- Exceptions to these typical assignments can occur.
Key Terms & Definitions
- IP Address — a unique 32-bit address identifying a device on a network, written in dotted decimal notation.
- Octet — a group of 8 bits within an IP address, representing values from 0 to 255.
- Dotted Decimal Notation — the standard format for writing IP addresses, using dots to separate four octets.
- Dynamic IP Address — an IP address assigned automatically by a network using DHCP.
- Static IP Address — an IP address manually configured on a device, usually reserved for specific roles.
- MAC Address — a hardware address unique to a device's network interface card.
Action Items / Next Steps
- Review the basics of IP addressing; prepare for an upcoming lesson on subnetting.