Network Layer Lesson-1
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Network Layer (Class Full and Class Less IP Addressing)

Network Layer, Class Full and Class Less IP Addressing

Network Layer, Class Full and Class Less IP Addressing
Network Layer (CCNA) Lesson-1

CCNA

Class Full and Class Less IP Addressing

Network Layer :-

Controller communications between broadcast domains.

You can go from one broad cast domain to another broadcast domain throw layer 3 (router).

The function of layer 3 (Network layer) sends data between broadcast domain.

The protocol data unit at layer-3 is called a packet.

The addresses schema at layer-3 is IP addresses.

The IP address is 32bits in length written in 4 fields of 8 bits each separated by dot.

Ex: 10.202.10.202 each one of these values range between 0 – 255.

Class full IP addressing

1st octet: 12.12.12.12 number in red is the first octet.

Ip address was broken into classes called class full IP addressing :-

Class

Value of 1st octet

Subnet mask

Class less inter domain routeing notation (CIDR)

EX:

A

1-126

255.0.0.0

/8

10.202.10.202/8

B

128-191

255.255.0.0

/16

130.100.202.10/16

C

192-223

255.255.255.0

/24

200.202.10.10/24

D

224-239

Used in multi casting

E

Experimental and unused

Class less inter domain routeing notation (CIRD): instead of writing 255.0.0.0 -> /8

/8 is the number of bits are on in the subnet mask.

127.0.0.0 Is reserved for testing

127.0.0.1 Is called the local loop (TCP/IP protocol stack installed on your machine)

IP Address has two portions:-

  1. Network portion
  2. Host portion

Subnet mask: - separate the network addresses from the host addresses.

As long as corresponding bit in the subnet mask is off then that bit is belong to the host portion.

EX: 202.10.202.0/24

The first network address in this network is 202.10.202.1

The last network address in this network is 202.10.202.255

  • You can’t use 202.10.202.0 because this is network address itself
  • You can’t use 202.10.202.255 because this is broad cast

The valid range of address is from 1 till 254

Using this formula 2^n -2 , where n is the number of host bit.

Like 255.255.255.0 8-bit

2^8 -2 = 254

Class less IP Address:-

Now IP address is not class full.

Moving from class full to class less because less amount of addresses in class full is 254 class C and maybe you want to buy less than that number of addresses, so class full want work (no need to get 254).

  • Unicast :- is one to one transmission
  • Broadcast :- is one to everybody transmission, like-junk mail
  • Multicast: - is one to many transmission but the host have to be subscribe to the feed.

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TOPICS:  CCNA