Introduction to Networking: Module 05 - Network Implementation, Exercises of Operating Systems

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CTS

Introduction to Networking

Module 05 – Network

Implementation

Binary to Decimal Conversion

10000000 010000000 00100000 00010000 00001000 00000100 00000010 00000001

IP Addresses

• The IP address includes both the network and

the host address (network always on the left, host

always on the right).

• The subnet mask (32-bit number) is associated

with each IP address. The subnet mask identifies

the network portion of the address.

• In binary form, the subnet mask is always a series

of 1's followed by a series of 0‘s.

• A simple (decimal) mask might be 255.255.255.0.

IP Addresses

A computer only knows binary (0s and 1s)

An IP address in IP version 4 has

32 bits

(separated by periods into 4 octets)

IP Addresses

IP Addresses have 2 Parts:

Network Number and Host Number

In the IP Address 192.168.10.150,

the Network Number is 192.168.

and the Host Number is 150.

The Correct Notation is 192.168.10.

and 0.0.0.

IP Addresses Classes

Class Decimal in

first octet

Binary in

first octet

A 0-126 00000000 -

B 128-191 1000000 -

C 192-223 11000000 –

Default Subnet Mask

• In binary, the highest number 8 bits can

designate is 11111111 or 255 in decimal.

IP Class Subnet masks

Class Subnet mask - Decimal Subnet mask - Binary

A 255.0.0.0 11111111.00000000.00000000.

B 255.255.0.0 11111111.11111111.00000000.

C 255.255.255.0 11111111.11111111.11111111.

Network Numbers

• The network number is the first address in an

address range and is used to identify the

network itself.

• For the network address, the host portion of

the address contains all 0's.

– Class A network address: 115.0.0.

– Class B network address: 154.90.0.

– Class C network address: 221.65.244.

Host Addresses

Each host must have a unique IP address.

Each host on the same network must use the same subnet mask.

When assigning IP addresses to hosts, you cannot use the first or last address in the range (reserved for the network and broadcast addresses)

For example:

Class A: 115.0.0.0, the host range is 115.0.0.1 to 115.255.255.254.

Class B:154.90.0.0, the host range is 154.90.0.1 to 154.90.255.254.

Class C: 221.65.244.0, the host range is 221.65.244.1 to 221.65.244.254.

Subnetting Facts

Subnetting is the process of dividing a large network into smaller networks.

As your network grows, you will need to create subnets to:

• Increase the number of devices that can be added to the LAN
• Reduce the number of devices on a single subnet to reduce congestion and collisions
• Reduce the processing load placed on computers and routers
• Combine networks with different media types within the same internetwork (subnets can not be used to combine networks of different media type on to the same subnet)

Note: It is possible to use subnet masks that do not use an entire octet. For example, the mask 255.255.252.0 uses six extra binary bits in the third octet.

APIPA

Automatic Private IP Addressing is a feature that's

built into Windows Operating Systems that enable

the operating system to assign itself an IP address in

the event that a DHCP server is unreachable.

If a host can't reach the DHCP server, APIPA

automatically assigns the host an IP address in the

range of 169.254.0.0 to 169.254.255.254, so they can

communicate on the LAN.

Static (manual) assignment

Using static addressing, IP configuration information must be manually configured on each host.

Use static addressing:

• On networks with a very small number of hosts.
• On networks that do not change often or that will not grow.
• To permanently assign IP addresses to hosts that must have always have the same address (such as printers, servers, or routers).
• For hosts that cannot accept an IP address from DHCP.
• To reduce DHCP-related traffic.

Note: Static addressing is very susceptible to configuration errors and duplicate IP address configuration errors. Static addressing also disables both APIPA and DHCP capabilities on the host.

Routing Facts

A router is a device that routes packets from one network to another network. Routers receive packets, read their headers, find addressing information, and send them on to their correct destination. Routers can forward packets through an internetwork by maintaining routing information in a database called a routing table.

The routing table typically contains the following information:

• The address of a known network
• The interface or next hop router used to reach the destination network
• A cost value ( metric) that identifies the desirability of the route to the destination network (using distance, delay, or cost)
• A timeout value that identifies when the route expires

Routing Protocol

Characteristics Facts

Scope

• IGP or EGP

Metric

• hop count or link cost

Routing update method

• Distance vector or Link State

Classless Inter-Domain Routing (CIDR)

• Classful or classless