CCNA learning: IP Address

IPv4 Address: 32 bits

IPv6 Address: 128 bits

Dotted demical: 192.168.0.1

1 octet = 1 byte = 8 bits

Catagory:

Class A: Network 8 bits(start with 0) Host 24 bits       --> 0 - 127.x.x.x 

Class B: Network 16 bits(start with 10) Host 16 bits    --> 128 - 191.x.x.x

Class C: Network 24 bits(start with 110) Host 8 bits    --> 192 - 223.x.x.x

Class D: start with 1110                                                 --> 224 - 239.x.x.x

Special IP address

127.0.0.1:             loopback address

255.255.255.255: broadcast address

0.0.0.0:                 any network

Host part is 1:     all host in this sub network, sub network broadcast

Such as 136.78.255.255 representate all the hosts in 136.78 sub network

Host part is 0:     sub network

Private IP Address( Intranet Use only)

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

Calculate Host Address

Class A: 24 host address --> 2^24 -2 = 16777214

              8 network address --> 2^8 -2 = 254

Class B: 16 host address --> 2^16 -2(x.x.0.0/x.x.255.255) = 65534

              16 network address --> 2^16 -2 = 65534

Class C: 8 host address --> 2^8 -2 = 254

              24 network address --> 2 ^24 -2 = 16777214

Subnet Mask

32 bits

Class A: 255.0.0.0         --> /8

Class B: 255.255.0.0     --> /16

Class C: 255.255.255.0 --> /24

1：网络位

0：主机位

Subneting

without subneting, the broadcast signal will reach every host.

with subnet, the broadcast signal will be blocked by router

Use host part to make sub network

Example:

Class C

IP ADDRESS: 192.168.10.0  Subnet Mask: 255.255.255.192(/26)

Subnet number: 2^2 -2 =2

Host number: 2^6 -2 = 62

Subnet: 192.168.10.64 / 192.168.10.128 (256 - 192 = 64)

Subnet broadcast: 192.168.10.127 / 192.168.10.191

Subnet IP:

192.168.10.65 - 192.168.10.126

192.168.10.129 - 192.168.10.190

Class B

IP Address: 172.16.0.0 Subnet Mask: 255.255.192.0(/18)

Subnet number: 2^2-2 = 2

Host number: 2^14 -2 = 16382

Subnet: (256 - 192=64) 172.16.64.0/172.16.128.0

Subnet broadcast: 172.16.127.255/172.16.191.255

Subnet IP:

172.16.64.1 - 172.16.127.254

172.16.128.1 - 172.16.191.254

Class B

IP Address: 172.16.0.0 Subnet Mask: 255.255.255.224(/27)

Subnet number: 2^11-2=2046

Host number: 2^5 -2 = 30

Subnet:(256-224=32) 172.16.0.32......172.16.255.192

Subnet broadcast: 172.16.0.63.......172.16.255.223

Subnet IP:

172.16.0.33 - 172.16.0.62

.....

172.16.255.193 - 172.16.255.222

VLSM: Variable-length subnet masks

According to the number of host, the subnet mask be provided

Save IP address. Need the router support (RIPv2, OSPF, EIGRP BGP)

Example:

192.168.1.64 - 192.168.1.79

Subnet Mask: /28

Example:

199.188.19.0/27

Host number: 2^5-2=30

Example:

Corporation: 172.16.0.0/16

Division A: 172.16.12.0/22

Division A has A B C D four parts

Range of address: 172.16.12.0 - 172.16.15.255

D parts: request 2 vlan, each vlan for 200 customers

A,B,C parts: connect to 3 ethernet, each need 24 port switcher

Part D:

200 --> 2^8 -2 = 254 --> Subnet Mask: /24

172.16.12.0/24

172.16.13.0/24

Left: 172.16.14.0/24 172.16.15.0/24

Part A, B, C

24 --> 2^5 -2 = 30 --> Subnet Mask: /27

Part A: 172.16.14.0/27

Part B: 172.16.14.32/27

Part C: 172.16.14.64/27

Left: 172.16.14.96/27 172.16.14.128/27 172.16.14.160/27 172.16.14.192/27 172.16.14.224/27 172.16.15.0/24

Router

2 --> 2^2 -2 =2 --> Subnet Mask: /30

Router A and Router D: 172.16.14.224 /30

Router B and Router D: 172.16.14.228 /30

Router C and Router D: 172.16.14.232 /30

CIDR(Classless Inter Domain Route)

Define Subnet Mask same network as a block

199.0.0.0/8 --> Superneting

save network items, decrease the router table

Example:

Route D connect four subnet:

1. 192.16.12.0/24

2. 192.16.13.0/24

3. 192.16.14.0/24

4. 192.16.15.0/24

Routing table for D:

192.16.12.0/24

192.16.13.0/24

192.16.14.0/24

192.16.15.0/24

Route E connect to Route D

Routing table for E:

192.16.12.0/22