Assignment 4

Assignment 4

Name: Kshitij Chandrakar
Batch: 5
SAP: 500124827

Theory

1. IP Addressing Basics #

IPv4 and IPv6 Addressing #

  • IPv4 (Internet Protocol Version 4): #
    • Uses a 32-bit addressing scheme
    • allows around 4.3 billion unique addresses
    • written in decimal format, separated by dots (For Ex: 192.168.1.1)
  • IPv6 (Internet Protocol Version 6): #
    • Uses a 128-bit addressing scheme
    • written in hexadecimal format, separated by colons (For Ex: 1011:09pa:00a2:0000:0000:9fe3:9102:4332).

Public vs. Private IP Addresses #

  • Public IP Addresses: #
    • Routable on the internet and assigned by ISPs (For Ex 8.8.8.8).
  • Private IP Addresses: #
    • Used within local networks and not routable on the internet.
      Their Address Ranges are:
      • Class A: 10.0.0.0 – 10.255.255.255
      • Class B: 172.16.0.0 – 172.31.255.255
      • Class C: 192.168.0.0 – 192.168.255.255

Subnet Masks #

  • A subnet mask defines the network and host portions of an IP address.
  • For Ex: 255.255.0.0 indicates that the first two octets represent the network portion, and the last two octet represents hosts.

2. Subnetting #

CIDR Notation and Its Role in Subnetting: #

  • CIDR: Classless Inter-Domain Routing
  • A method to allocate IP addresses efficiently by eliminating the rigid class-based addressing system.
  • Expressed using a suffix (For Ex: 192.168.1.0/24 means 24 bits for the network, 8 bits for hosts).
  • Subnetting allows networks to be divided into smaller subnetworks, improving security and reducing IP wastage.
  • Example: Splitting 192.168.1.0/24 into four subnets:
    • 192.168.1.0/26
    • 192.168.1.64/26
    • 192.168.1.128/26
    • 192.168.1.192/26

3. Supernetting #

Definition and Advantages: #

  • Supernetting: The process of combining multiple smaller networks into a larger one by modifying the subnet mask.
  • Reduces the number of routing table entries, improving efficiency.
  • Helps ISPs aggregate multiple customer networks.

Real-World Applications: #

  • Used in ISP route aggregation to reduce the number of advertised routes.
  • Helps in enterprise network management by consolidating multiple subnets.
  • Example: Combining four /26 networks (192.168.1.0/26, 192.168.1.64/26, 192.168.1.128/26, 192.168.1.192/26) into a single /24 network (192.168.1.0/24).

Practical

1. Subnetting a Corporate Network #

Departments: #

  1. HR: 50 Hosts
  2. IT: 100 Hosts
  3. Finance: 30 Hosts

Subnets Sizes #

Subnets Are Sized by Powers of 2. Therefore nearest power of 2 for each department. Subnets are determined by the formula:

Subnet = 32 - Number of Bits

  1. HR: 64 [ 6 Bits, /26 Subnet ]
  2. IT: 128 [ 7 Bits, /25 Subnet ]
  3. Finance: 32 [ 5 Bits, /27 Subnet ]

Subnet Assignment: #

(Allocating Sequentially We Have)

  1. IT (/25)
  • Network Address: 192.168.1.0/25
  • Broadcast Address: 192.168.1.127
  • Subnet Mask: 255.255.255.128
  • Usable IPs: 192.168.1.1 – 192.168.1.126
  1. HR (/26)
  • Network Address: 192.168.1.128/26
  • Broadcast Address: 192.168.1.191
  • Subnet Mask: 255.255.255.192
  • Usable IPs: 192.168.1.129 – 192.168.1.190
  1. Finance (/27)
  • Network Address: 192.168.1.192/27
  • Broadcast Address: 192.168.1.223
  • Subnet Mask: 255.255.255.224
  • Usable IPs: 192.168.1.193 – 192.168.1.222

2. Subnetting an ISP Network #

Supernetting combines multiple contiguous networks into a single network. This reduces the number of routing table entries, Thus improving efficiency.

Given Networks: #

  • 192.168.10.0/24
  • 192.168.11.0/24
  • 192.168.12.0/24
  • 192.168.13.0/24

Finding Common Bits in the Network Address #

Since the subnet is /24, the third octet changes and is relevant. Thus, we find common bits in the third octet.

Given Values in 8 Bits: #
  • 10 : 00001010
  • 11 : 00001011
  • 12 : 00001100
  • 13 : 00001101

We can See here, that only the last 6 bits remain constant. thus, to include all 4 networks we need a /22 Mask. (16 + 6 = 22) 16 for the first 2 octets, 6 for the 3rd one

New Network addresses #

Since the new Subnet mask is /22, The Network Address 192.168.10.0/22 would cover all the four networks.

Advantages #

  • For the router, it reduces the number of entries in the routing table. (from 4 /24 Entries to 1 /22)
  • The lower entry count improves efficiency and simplifies the network Management for Larger Networks.

3. Subnetting a University Network #

Departments: #

  1. Engineering: 2,000 hosts
  2. Medical: 1,500 hosts
  3. Management: 1,000 hosts
  4. Library: 500 hosts
  5. Admin: 300 hosts

Subnets Sizes #

Subnets Are Sized by Powers of 2. Therefore nearest power of 2 for each department. Subnets are determined by the formula:

Number of Bits are the nearest larger power of 2.

Subnet = 32 - Number of Bits

  1. Engineering: 2048 [11 Bits, /21 Subnet]
  2. Medical: 2048 [11 Bits, /21 Subnet]
  3. Management: 1024 [10 Bits, /22 Subnet]
  4. Library: 512 [9 Bits, /23 Subnet]
  5. Admin: 512 [9 Bits, /23 Subnet]

Subnet Assignment: #

(Allocating Sequentially We Have)

  1. Engineering (/21)
  • Network Address: 172.16.0.0/21
  • Broadcast Address: 172.16.7.255
  • Usable IPs: 172.16.0.1 – 172.16.7.254
  • Subnet Mask: 255.255.248.0
  1. Medical (/21)
  • Network Address: 172.16.8.0/21
  • Broadcast Address: 172.16.15.255
  • Usable IPs: 172.16.8.1 – 172.16.15.254
  • Subnet Mask: 255.255.248.0
  1. Management (/22)
  • Network Address: 172.16.16.0/22
  • Broadcast Address: 172.16.19.255
  • Usable IPs: 172.16.16.1 – 172.16.19.254
  • Subnet Mask: 255.255.252.0
  1. Library (/23)
  • Network Address: 172.16.20.0/23
  • Broadcast Address: 172.16.21.255
  • Usable IPs: 172.16.20.1 – 172.16.21.254
  • Subnet Mask: 255.255.254.0
  1. Admin (/23)
  • Network Address: 172.16.22.0/23
  • Broadcast Address: 172.16.23.255
  • Usable IPs: 172.16.22.1 – 172.16.23.254
  • Subnet Mask: 255.255.254.0