22/06/2011:CIDR (CLASSLESS INTER DOMAIN ROUTING)

CIDR (CLASSLESS INTER DOMAIN ROUTING)

class	Default subnetmask	Net address	Host address	Cidr
	w.x.y.z
A	255.0.0.0	w	x.y.z	8
B	255.255.0.0	w.x	y.z	16
C	255.255.255.0	w.x.y	z	24

NETWORK ADDRESS DAN BROADCAST ADDRESS

Network addresss	Broadcast address
1st address	Last address
10.0.0.0	10.255.255.255
172.16.0.0	172.31.255.255
192.168.0.0	192.168.255.255

HOST

Class A:2ⁿ – 2 ; kenapa perlu tolak 2, sbb dlm host ada net address dan broadcast        

                           Address

Cara nak kira lebihan ID.

Contoh:

1.  192.168.100.10/25
2. 192.168.100.1/31
3. 172.16.100.1/18
4. 10.10.10.10/15
5. 172.30.30.30/23
6. 192.168.10.10/24

Mula2 mesti kena kenal ID dok lam clz mane

Lepas 2 tgk dia pnye CIDR.

EXAMPLE:

• 192.168.100.10/25 = class C

W	x	y	Z
1111111.	11111111.	11111111.	10000000

2ⁿ = 2¹ (lebihan bit network dalam host oktet)

    = 2, net address 

2ⁿ = 2⁷ (lebihan bit host dalam host oktet)

    = 128 -2 = 126 usable host (-2, include net & broadcast)

• 192.168.100.1/31 = class C

W	x	y	Z
1111111.	11111111.	11111111.	11111110

2ⁿ = 2⁷ (lebihan bit network dalam host oktet)

    = 128, net address 

2ⁿ = 2¹ (lebihan bit host dalam host oktet)

    = 2 -2 = 0 usable host (-2, include net & broadcast)

• 172.16.100.1/18 = class B

W	X	y	Z
1111111.	11111111.	11000000.	00000000

2ⁿ = 2² (lebihan bit network dalam host oktet)

    = 4, net address 

2ⁿ = 2¹⁴ (lebihan bit host dalam host oktet)

    = 16384 -2 = 16382 usable host (-2, include net & broadcast)

• 10.10.10.10/15 = class A

W	x	y	Z
1111111.	11111110.	00000000.	00000000

2ⁿ = 2⁷ (lebihan bit network dalam host oktet)

    = 128, net address 

2ⁿ = 2¹⁷ (lebihan bit host dalam host oktet)

    = 131072 -2 = 131070 usable host (-2, include net & broadcast)

•   172.30.30.30/23 = class B

W	x	y	Z
1111111.	11111111.	11111110.	00000000

2ⁿ = 2⁷ (lebihan bit network dalam host oktet)

    = 128, net address 

2ⁿ = 2⁹ (lebihan bit host dalam host oktet)

    = 512 -2 = 510 usable host (-2, include net & broadcast)

•   192.168.10.10/24 = class C

W	x	y	Z
1111111.	11111111.	11111111.	0000000

2ⁿ = 2⁰ (lebihan bit network dalam host oktet)

    = 1, net address 

2ⁿ = 2⁸ (lebihan bit host dalam host oktet)

    = 256 -2 = 254 usable host (-2, include net & broadcast)