Understanding IP Address Classes

• Simple network configuration is crucial for effective communication between devices.

IP Address Classes

• Class A IP addresses range from 1-126 in the first octet.
• Class A uses a network ID & Host ID format of N.H.H.H
• Class A has a default subnet mask of 255.0.0.0.
• Class A offers 126 networks (2^7 -2) and 16,777,214 usable host addresses per network (2^24 - 2).
• Class B IP addresses range from 128-191 in the first octet.
• Class B uses a network ID & Host ID format of N.N.H.H
• Class B has a default subnet mask of 255.255.0.0.
• Class B offers 16,382 networks (2^14 - 2) and 65,534 usable host addresses per network (2^16 - 2).
• Class C IP addresses range from 192-223 in the first octet.
• Class C uses a network ID & Host ID format of N.N.N.H.
• Class C has a default subnet mask of 255.255.255.0.
• Class C offers 2,097,150 networks (2^21 - 2) and 254 usable host addresses per network (2^8 - 2).
• Class D IP addresses range from 224-239 and are reserved for multicasting.
• Class E IP addresses range from 240-254 and are experimental, used for research.
• Class A addresses from 127.0.0.0 to 127.255.255.255 are reserved for loopback and diagnostic functions.

Private IP Addresses

• Class A private networks use the IP range 10.0.0.0 with a subnet mask of 255.0.0.0, and address range of 10.0.0.0 - 10.255.255.255.
• Class B private networks utilize the IP range 172.16.0.0 – 172.31.0.0 with a subnet mask of 255.240.0.0, and address range of 172.16.0.0 - 172.31.255.255.
• Class C private networks use the IP range 192.168.0.0 with a subnet mask of 255.255.0.0, and address range of 192.168.0.0 – 192.168.255.255.

IPv4 Address Structure

• IPv4 addresses are 32 bits long.
• In binary form, an IPv4 address is a 32-bit string of 1's and 0's, divided into four octets (8 bits each) separated by dots.
• Each octet ranges from 00000000 to 11111111 in binary.
• In decimal form, an IPv4 address consists of four numbers separated by dots, like 192.168.1.1.
• Each decimal number in an IPv4 address ranges from 0 to 255.

IPv4 Addressing Types

Class Full (FLSM)

• FLSM (Fixed Length Subnet Mask) subnetting involves subsets of equal size and an equal number of host IDs.
• Classful routing protocols do not send the subnet mask with their updates.
• An IPv4 address in classful addressing consists of three parts: network, subnet, and host, defined by the mask and Class A, B, and C rules.

Class Less (VLSM)

• VLSM (Variable Length Subnet Mask) subnetting allows for subnets of different sizes.
• VLSM is a type of subnetting method that is considered a subset.
• VLSM subnetting makes more efficient use of a given ID range.
• Classless routing protocols send the subnet mask with their updates.
• An IPv4 address in classless addressing consists of a prefix part and a host part.
• Classless addressing disregards Class A, B, or C designations.

Bits, Values, and Exponents

• 1 bit = 1 = 2^0
• 2 bits = 2 = 2^1
• 3 bits = 4 = 2^2
• 4 bits = 8 = 2^3
• 5 bits = 16 = 2^4
• 6 bits = 32 = 2^5
• 7 bits = 64 = 2^6
• 8 bits = 128 = 2^7
• 9 bits = 256 = 2^8
• 10 bits = 512 = 2^9
• 11 bits = 1024 = 2^10
• 12 bits = 2048 = 2^11
• 13 bits = 4096 = 2^12
• 14 bits = 8192 = 2^13

VLSM Example

• Network address: 172.168.0.0/16
• Router 0 requires addresses for 400 hosts on one side and 300 hosts on the other.
• Router 1 needs addresses for 600 hosts on one side and 500 hosts on the other.
• Router 2 needs addresses for 200 hosts on one side and 100 hosts on the other.
• Router 3 requires addresses for 50 hosts on one side and 25 hosts on the other.
• R0, R1, R2, R3 each use 8 IP addresses.

Network Computation Example

• Given host requirements: 600, 500, 400, 300, 200, 100, 50, 25, 2, 2, 2, 2 @600
• 10 bits are needed to accommodate 512 hosts (10 bits).
• Subnet Mask calculation: 32 - 10 = 22.
• NSM (Number of Subnet Mask) is /22.
• Subnet mask in binary: 11111111.11111111.11111100.00000000 or 255.255.252.0.
• Range calculation: 255-252 = 3 + 1 = 4.
• IP address range: 172.168.0.0 – 172.168.3.255 /22.
• The network address is 172.168.0.0 with a /22 subnet mask.
• The next network address in sequence is 172.168.4.0.
• For 500 hosts: NSM 32-9 = 23
• NSM = /23 = 11111111.11111111.11111110.00000000
• 255-254 = 1+1=++2
• 255.255.254.0
• R 172.168.4.0 -172.168.5.255/23
• 172.168.6.0
• For 400 hosts: R 172.168.6.0

Computer to Computer Connection

• In a simple computer-to-computer network:

• PC0: IP Address is 192.168.1.1 with Subnet Mask 255.255.255.0 and configured via NIC

• PC1: IP Address is 192.168.1.2 with Subnet Mask 255.255.255.0 and configured via NIC

• To establish a direct computer to computer connection:

• Assign the IP address and subnet mask for each device.

• Use the ipconfig command for PC0 and ping command for PC1 for verification.

Router Configuration Mode

• User EXEC Mode (Router>): Commands include ping, show (limited), enable.
• Privileged EXEC Mode (Router#): Includes all user EXEC commands, debug commands, reload, configure.
• Global Configuration Mode (Router(config)#): Commands include hostname, enable secret, ip route.
• Interface Commands (Router(config-if)#): Commands include ip address, ipx address, encapsulation, shutdown/no shutdown.
• Routing Engine Commands (Router(config-router)#): Commands include network, version, auto-summary.
• Line Commands (Router(config-line)#): Commands include password, login, modem commands.

Computer - Router - Computer Network

• PC0: NIC, IP 192.168.1.2, Subnet 255.255.255.0, Gateway 192.168.1.1
• PC1: NIC, IP 192.168.2.2, Subnet 255.255.255.0, Gateway 192.168.2.1
• ROUTER0: F 0/0, IP 192.168.1.1, Subnet 255.255.255.0, No Gateway, F 1/0, IP 192.168.2.1, Subnet 255.255.255.0, No Gateway
• Configure PC0 and PC1 parameters as well as the Router (Router0) to complete the setup.
• Press enter in the Router0 configuration console to view more details about the configuration.

Computer - Switch - Computer Network

• PC0: NIC, IP 192.168.1.1, Subnet Mask 255.255.255.0
• PC1: NIC, IP 192.168.1.2, Subnet Mask 255.255.255.0
• Switch: Configured with Fa 0/1 and Fa 1/1 ports for connectivity.
• Assign IP addresses and subnet masks and then use ipconfig and ping command to verify.

RJ45 Wiring Standards: T568A and T568B

• RJ45 connector: A modular 8-position, 8-pin connector.
• Used for terminating Cat5e or Cat6 cables.
• Pinout: A specific arrangement of wires dictating termination.
• Standards: ANSI, TIA, and EIA recognize two standards for Ethernet cables.
• T568A: One wiring standard.
• T568B: The other wiring standard, surpasses T568A.
• T568B is the default wiring scheme for twisted pair structured cabling.
• If unsure, choose T568B.

Ethernet Cable Types and Usage

Straight-Through Cable

• Use for connecting:
• Switch to router.
• Switch to PC or server.
• Hub to PC or server.

Crossover Cable

• Use for connecting:
• Switch to switch.
• Switch to hub.
• Hub to hub.
• Router to router.
• Router Ethernet port to PC NIC.
• PC to PC.

RJ45 Termination Standards

• Straight cable termination: Use either 568A or 568B.
• Crossover cable termination: Use 568A at one end and 568B at the other end.