IT2050 Computer Networks - Lecture 2 IP Addressing

TCP/IP Addressing

• Addressing in TCP/IP involves three types: Physical, Logical, and Port addresses.
• MAC Address is the physical address, set by the manufacturer, 48 bits in length, typically written in hexadecimal format.
• IP Address serves as the logical address, necessary for identifying devices on a network.

Physical Addresses

• Stored in Network Interface Cards (NIC), fixed and unchangeable.
• MAC addresses follow the Data Link Layer standard and are essential for Ethernet networking.

Logical Addresses

• IP Addresses exemplify logical addressing, extensively used with the TCP/IP protocol.
• Two IP versions exist:
  • IPv4 uses a 32-bit addressing scheme (e.g., 192.168.16.53).
  • IPv6 employs a 128-bit addressing scheme.

IP Version 4 (IPv4)

• Composed of four octets (bytes), each byte ranging from 0 to 255.
• The minimum IPv4 address is 0.0.0.0, and the maximum is 255.255.255.255.

Network ID and Host ID

• An IP address comprises Network ID plus Host ID.
• Class A (1 byte Net ID, 3 bytes Host ID), Class B (2 bytes Net ID, 2 bytes Host ID), Class C (3 bytes Net ID, 1 byte Host ID).

IPv4 Address Classes

• Class D is designated for multicasting, while Class E is reserved for experimental purposes.
• Private IP address ranges include:
  • Class A: 10.0.0.0
  • Class B: 172.16.0.0 to 172.31.0.0
  • Class C: 192.168.0.0 to 192.168.255.0

Special IP Addresses

• Network Address: Designates the entire network, all host bits are 0.
• Direct Broadcast Address: Targets all hosts within a specific network, all host bits are 1.
• Loopback Address: Standard loopback address is 127.0.0.1 for testing.

Classful Addressing

• Traditional addressing method where each class has a fixed size subnet mask.

Subnetting and Classless Addressing

• Subnetting divides a single network into multiple subnets, enhancing efficiency.
• Classless Addressing uses CIDR (Classless Inter-Domain Routing) and specifies variable-length subnet masking.
• Example: For network 150.100.0.0/16, subnetting can create multiple subnets using bits from the host portion for subnetting.

Variable Length Subnet Masking (VLSM)

• Allows different subnets within the same network to have varying subnet masks.
• More efficient for organizations with unequal device counts in different subnets.

Example of Subnetting

• Block 130.34.12.64/26 can be subdivided into multiple smaller subnets using VLSM.

The Need for Multiple Subnets

• An organization can require different subnet sizes for specific needs. For instance:
  • 2 subnets with 64 addresses
  • 3 subnets with 16 addresses
  • Total subnets can exceed original class capacity through effective subnetting strategy.

Summary

• Understanding TCP/IP addressing is crucial for network configuration and management.
• Differentiation between MAC (physical) and IP (logical) addresses is essential.
• IPv4 remains a widely utilized version while transitioning to IPv6 is underway.
• Subnetting techniques like VLSM improve address efficiency and network flexibility.

This quiz covers Lecture 2 of IT2050 on Computer Networks, focusing on IP Addressing. It delves into different types of addresses including physical, logical, and port addressing, essential for understanding TCP/IP protocols.