CCNA Course Five

VLSM (variable eldest son netmask) is the process of dividing the subnet

The subnet mask and IP address are the IP address of the network address (0&1 = = 0; 1&1 = = 1)

In a nutshell, the IP address and subnet mask are written in binary, and the subnet mask of 1 corresponds to the portion of the IP address that is part of the network

The portion of the subnet mask to 0 corresponds to the portion of the IP address that is the host portion.

Live: The host part is all 0, is the network address of the subnet, can not assign to the PC;

The host part is all 1, is the broadcast address of the subnet, can not assign to the PC

CIDR non-class inter-domain routing, which can be understood as a summary of routes

To divide the subnet step:

A. Number of subnets known to be separated:

1. Figure out the need to borrow the host part of a few bits into the network portion (2 of the n is slightly larger than the number of subnets, N is the number of host bits to borrow)

2. Calculate subnet mask for subnets

3. Reach the subnet segment (network address)

4. The first IP address that can be assigned to a PC under each subnet; the last IP address that can be assigned to the PC; The subnet's broadcast address.

Two. The number of IP addresses required for each subnet is known

1. Calculate the number of bits required for the host part (2 of the n is slightly larger than the number of IP, n is the host bit)

2.32-host bits = = number of network bits

3. Calculate subnet mask for subnets

4. Reach the subnet segment (network address)

5. The first IP address that can be assigned to a PC under each subnet; the last IP address that can be assigned to the PC; The subnet's broadcast address.

The broadcast address of a subnet is the network address of the next subnet-1

The first IP address that can be assigned to a PC, which is the network address of the subnet + 1

Configuration of static routes:

Router (config) #ip Route 10.1.1.0 255.255.255.0 fastethernet 0/0

Or:

Router (config) #ip Route 10.1.1.0 255.255.255.0 1.1.1.1

Comments:

10.1.1.0 255.255.255.0 indicates the target network

FastEthernet 0/0 means to go to the target network from the local interface to send out

1.1.1.1//To the destination network to which IP address (this address must first be reached)

CCNA Course Five