Networking Foundation Classroom Series – 29/Sep/2019

Usecases

• Cloud
• Errors:
  • SSH timed out
  • jdbc connection timed out
• Security:
  • How to read the Network Logs

Topics

• Binary arthmetic
• IPAddressing
• Subnetting

Principle

• A sytem can connect to only other system in same network.

What is IP Address ?

• Unique address to identify a system with in a network.

• Network

• What does IP Address Reprsent?

  • Network Id
  • Host Id

• How do i identify What is Network Id & Host Id? Eg: 192.168.0.10, 192.168.0.100

  • Subnet Mask is required to identify Network ID & Host Id
  • Subnet Mask has two representations
    • Decimal Repesentation
    • Binary Repesentation

• Ip Address is 4 bytes in size. Represented as X.X.X.X => X => byte => (2)^8-1 => 0 – 255

• Subnet mask

  ipconfig
  

  255.255.255.0 255.255.0.0 255.0.0.0

• Find the size of the devices that can be connected to the network

A 10.10.100.98 255.0.0.0

Network Id => 10 Host id => 10.100.98 => size => 3*8 => 24

size of this network is => (2^24)-2

• Identify the Wrong One in the below image

Problems with Decimal Approach

• 255.255.255.0 ~> 250
• 255.255.0.0 ~> 65000
• 255.0.0.0 ~> 167 lakhs

Lets move to Binary Approach

• Start looking at subnet mask as binary
• sequence of 1 => Network Id
• sequence of 0 => Host Id Examples Ip: 192.168.0.3 sm: 255.255.255.248 smbinary: 11111111.11111111.11111111.11111000 size of Network => Number of Zeros =>3 => 2^3-2 => 6 CIDR Notation => NetworkID/count of number of 1

192.168.0.0/29

Ip: 192.168.0.3 sm: 255.255.255.128 smbinary: 11111111.11111111.11111111.10000000 size of Network => Number of Zeros =>7 => 2^7-2 => 126 192.168.0.0/25

Ip: 192.168.0.3 sm: 255.255.254.0 smbinary: 11111111.11111111.11111110.00000000 size of Network => Number of Zeros =>9 => 2^9-2 => 510

CIDR Notation => 10.10.0.0/17 subnet mask => 11111111.11111111.10000000.00000000 Size => 32-17 = 15 bits => 2^15-2

CIDR Notation => 171.12.0.0/12

CIDR Notation => 192.168.0.0/23

Excercise:

1. Create a network which can connect to 1000 systems A. 10 bits are required for host size. CIDR Notation => 192.168.0.0/22

2. Create a network which can connect to 5000 systems A. 13 bits are required for host size CIDR Notation => 10.10.0.0/19

Private CIDR Ranges

• Some Reservations for Usage:
  • 10.0.0.0/8
  • 172.16.0.0/12
  • 192.168.0.0/16