The Computer Networks And Computer Communication

Published Date: 02 Nov 2017

Computer communication are nothing but a collection of computer and hardware devices connected through a communication channel or medium. The Computer Networks are helpful to transfer data from different Networks. This is one of the major technological developed which has helped in the growth of Internet.

There are three different types of Networks

LAN (Local area network): They are used to connected closely located area such as Universities, School, Within Building,etc

MAN (Metropolitan area network): They are used to connect different networks with a city, town or a collection of street.

WAN (Wide area network): They are used to connect a larger geographical area across different cities and countries.

The Computer Networks works based on a set of rules and topology,

TOPOLOGY:

They are nothing but a structure or skeleton of a nework. They works on this structure.

Types Of Topology:

Tree network

Bus network

Ring network

Star network

Mesh network

The most important aspect in Computer Networks is that cables which found at the Physical layer in OSI Model (Reference Model) as well as in TCP/IP Model (Working Model). The cables play a vital role in connecting different networks inorder to communicate with each other. There are many different kinds of cables used based on their need. The different types of cables are

Twisted Pair : They are a two pairs of wire twisted to each other. They are help to eliminate the external electromagnetic Interference. The twisted pair is classified into three different types (a) Shielded (b) unshielded (c)Foiled

Co-axial: These cables are made up of outer shield to protect the cable and central conductor to transfer the signals.

Ethernet: This kind of cable used is RJ-45 which is normally used to connect computer and router directly

Optical fibre: The optical fibre cables are made of central core made up of glass and cladding which is used a protective layer for the cable.

Depending on the distance of the communication various types of cables are used to used network devices or computers.

OBJECTIVE OF THE REPORT.

The main objective of this report is to introduce and analyze the Routing and Switching Network Protocol. The Routing and Switching Protocol is used to Configure for different kinds of router and switches.

OUTLINE

The report consists of 4 laboratory Session. They are as follows

Lab 2 : Serial Connections

Lab 3 : IPv4 Addressing

Lab 4 : VLANs/Ethernet Networks

Lab 5 : Routing Information Protocol

2. SERIAL CONNECTION

The serial connector is referred to as Serial Interface. The usual Serial Interface used is DB-60 and also DB-60 on one side and Winchester-type connector on the end. The serial communication is used to transfer data bit by bit in sequential manner. The DB-60 serial connector contains 60 pins.

Figure 2.1

TYPES SERIAL CONNECTIONS

The type of connector used in Serial connection is DB-60.There are two types of transmission mode.

Synchronous Mode: This is the kind of a transmission mode which is often used by serial connection. This mode helps us to transfer data with a flow and in a timely manner. It helps the receiver to receive data in a proper sequence without any delay in packets.

Asynchronous Mode: This is a kind of transmission mode which is the opposite of Synchronous transmission mode. It inserts a start bit to indicate the data flow and a stop bit to indicate the receiver about the end of data flow.

2.2 CONFIGURING THE SERIAL INTERFACE

To configure the Serial Interface first we should log into the Router where the Serial the Interface has to be configured.

Router>enable

Router# Show Interface Serial 0/1

This command helps us to see the serial interface connection the IP address, Encapsulation, encoding, etc which has been assigned and keep a note of the things to be modified. The serial 0/1 is the number of the serial port.

Router# configure terminal

Router(config-if)# ip address 192.168.1.1 255.255.255.0

This command is used to assign IP address to the serial interface to have an unique identification of that interface. 255.255.255.0 is a subnet mask used along with IP address.

Router(config-if)#no shutdown

This command is used to make the interface manually up.

Router(config-if)#Bandwidth

This command is used to fix the bandwidth or data rate for the interface.

Router(config-if)#clock rate 6400

This command is used to set the clock time of data rate. This can be configured only on the Data communicating equipment side because this side is configured by the ISP(Internet service provider).

Router(config-if)#nrzi-encoding

This command is used encode the data in nrzi form and transfer the data. The receiver should also follow the same encoding technique to recover the data.

Router(config-if)#no nrzi-encoding

This command is used to return to default encoding form

Router(Config-if)#encapsulation PPP

This command is used to encapsulated the data in different protocol. Some of the encapsulation protocols are HDLC (High Level data link control), PPP (Point to Point Protocol), SDLC (Synchronous data link control), etc

2.3 CONFIGURING ASYNCHRONOUS LINES

This type is less often used. They are mostly used to connect PC to Modem, printers and routers using console port.

Router>en

This command helps us to navigate to privilege mode.

Router# show line

This command help us to display the different line in asynchronous lines like auxiliary port, virtual terminal port,etc

Router# configure terminal

This command helps us to navigate to global configuration mode.

Router(config-line)#line aux 0

This command helps us to configure auxiliary port 0

Router(config)#interface async 65

This command is used to select the asynchronous interface.

2.4 SUMMARY

The Serial connection is used to interconnect the hardware devices using DB-60 connectot. The serial interface is configures into two different types a)synchronous lines and b)asynchronous lines according to the need.

3. IPv4 ADDRESSING

IP Address is referred to as the Internet protocol. It is nothing but a 32 bit address which is assigned to the devices. Every device has an unique address so that they can identified easily. The IP address consist of a host id and network id. There are two types IP Addressing they are IPv4 and IPv6

3.1 NETWORK CLASSES

There are 5 classes of network addressing they are

CLASS A- 1 to 126

CLASS B- 128 to 191

CLASS C- 192 to 22223

CLASS D- 224 to 239

CLASS E- 240 to 254

FIGURE 3.1

3.2 IP ADRESSING

IP addressing is one the most important aspect in designing a network. IP address are assigned to the devices inorder to identify them in a network. IP address is a 32 bit address and are represented by dotted decimal form. Here is an example of the IP address.

DOTTED DECIMAL

189.9.1.49

BINARY

10111101000010010000000100110001

In the above given example the address,

189.9.1.0- it is the Network address

.49- is the Host addresss

They are two of IP addressing

STATIC

DYNAMIC

In Static IP addressing the IP address are manually entered are given by the Administrator. This process is done in Intranet Environment like Companies and LAN setup.

Dynamic IP addressing is normally automatically assigned by every device using DHCP (Dynamic Host Configuration Protocol). In DHCP the devices are assigned a IP address for a given period of time, when this time expires the device is assigned with a another IP.

3.3 SUBNETTING

Like in IP address, the subnetting also plays a major role in addressing of a network. Subnetting is nothing but a logical division of network. Using this a number of networks can be found which can work independently. Without the help of Subnetting it is impossible to connect the devices and make them communicate with each other. IP address alone can not make the devices to communicate with each other. IP address and subnet together helps us to create a network and make the devices to communicate with each other. There is a default subnet mask assigned to each class of IP address. They are

Class A- 255.0.0.0

Class B- 255.255.0.0

Class C- 255.255.255.0

The subnet address is also a 32 bit address. They are also just represented as IP address with dotted decimals.

BINARY

11111111111111111111111100000000

Dotted Decimal

255.255.255.0

FIGURE 3.2

The above Given table gives us a clear and quick picture of how the IP and subnet address are used.

3.4 CONFIGURING IP ADDRESS TO ROUTER

Router>en

This command helps us to navigate to privilege mode

Router# configure terminal

This command helps us to navigate to global configuration mode.

Router(config)#

This command helps us to make changes in the configurations of the router.

Router(config)# Interface serial 1/0

This command will help us to configure the setting in serial interface 0/1

Router(config-if)ip address 192.168.1.1 255.255.255.0

This command assigns the IP and subnet address to serial interface 0/1

Router(config-if)#no shutdown

This command helps us to make the interface administratively up.

3.4 SUMMARY

The IP addressing is used to uniquely identify the device in the network and subnetting help us to sub-divide into various networks. It is manadatory thing that every device must have an IP inorder to communicate with other devices.

4 ETHERNET NETWORK

Ethernet is referred to as physical link layer technology used in Local Area Network(LAN). Ethernet are communication medium in Internet Protocol. It sends data in the form of packets or frames. Ethernet is standardized by IEEE 802.3. Ethernet can support a data rate of 10Mbps to 1000Mbps.

4.1 TYPES OF ETHERNET

10BASE-T

This kind of cable can support upto 10Mbps of data rate. Usually unshielded twisted pair is used for communication

100BASE-T

This kind of cable can support upto 100Mbps of data rate. They can support both half and full duplex communication.

100BASE-T4

This is kind of cable which has a four pair of twisted cable. Normally this kind of cable is classified as CAT3.

Figure 4.1

4.2 PHYSICAL LAYER

The Physical layer is the first layer found in the OSI Model. This is the layer where the cables are connected. MAC(Media access control) is used in the physical layer to be connected. This layer helps us to communicate in the network. Usually twisted pair or co-axial kind of cables are used to the devices.

Figure 4.2

4.3 MEDIA ACCESS CONTROL (MAC)

The Media access control is unique address in the devices. It is also called as physical address in the system. There are used to identify the device in the network. This plays a vital role for communication. Only with the help of MAC address we can communicate with other devices in a network without it is not possible to communicate. Usually the MAC address is a 48 bit address, the first 6 hexadecimal digits is a manufacture address and the last 6 hexadecimal digits for the device number. The MAC address is mapped to Address resolution protocol(ARP). The example of a MAC address found in the system is

PHYSICAL ADDRESS – 00-0A-9C-12-4B-9F

4.4 SUMMARY

Ethernet plays a vital role in communication between devices. Different types of Ethernet used for communication. Its illustration on the working of Ethernet in the physical layer is explained. The Media access control is used to connected the Ethernet to the devices.

ROUTING INFORMATION PROTOCOL

Routing is the process of selecting the path for the packets or frames to be forwarded. In simple terms routing means selection of route for the purpose communication. Routing Information protocol is one kind of rule used in routing. RIP is a distance vector protocol.

TYPES OF ROUTING

There are two types of routing used. They are

Static Routing

This is a kind of routing concept used to set a fixed route for the devices to communicate. This concept is used in a small setup of network like Intranet, Universities, etc. This kind of routing is defined by the administrator and cannot be changed often.

Dynamic Routing

This is a kind of routing which assigns its path automatically without anyone’s decision. This is done with the help of Protocols like RIP, RIP version2, OSPF, etc.

ROUTING INFORMATION PROTOCOL

Routing Information Protocol is a distance vector algorithm used to find the better path for the packets to be delivered. The maximum number of hop RIP works is 15 hop counts.

There are different types of RIP

RIP VERSION 1

This is one of the routing protocol used. The maximum number of hop is 16 and beyond that it is considered as unreachable or inoperable. Data is encapsulated as UDP segments. It keeps on updated for every 30 seconds. The disadvantage of RIP version 1 is that it does support discontiguous network.

Figure 5.1

RIP VERSION 2

This version of RIP also uses distance vector algorithm. They can support Classless inter domain routing (CIDR). Their hop is also limited to 15 counts. RIP has three header fields

Common field

Version field

Must be zero

They are also three route entry field

Address family Identifier

IP address

Metric

Figure 5.2

CONFIGURING RIP

Router>en

This command helps us to navigate to privilege mode.

Router# Configure terminal

This command helps us to navigate to global configuration mode.

Router (config)#interface serial 0/1

This command helps us to make changes in serial interface

Router (config-if)#ip address 192.168.10.10 255.255.255.0

This command is used assign IP address to the serial interface along with subnet.

Router (config-if)#no shutdown

This command helps to make the interface up

Router (config-if)# router rip

This command helps us to assign rip protocol to the router

Router (config-router)#version 2

This command helps us to assign RIP version 2

Router (config-router)#192.168.10.0

This command is given to assign the network

Router (config-router)#exit

Router (config)#exit

Router# undebug ip RIP

Figure 5.3

SUMMARY

The Routing Information Protocol helps us to find the better path for the packets to reach the destination. The advantages and disadvantages of different types of Static as well as Dynamic routing are explained.