CERTIFICATION

This is to certify that the project report entitled “computer networking” written and submitted to the School of Engineering and

Technology, Department of Computer Science and Engineering is my

original work and interpretation drawn therein are based on material

collected by ORDU HARMONY NDUDI with registration number

10setcse380 and roll number 100101152.

Project Supervisor

Place:

Date:

ACKNOWLEDGEMENT

I feel deeply indedted to Mr. Elems Ojadi, the trainer who delivered valuable lesson on

PC Maintenance, his indepth knowledge about the subject helped me understand the

subject in better way. His method of teaching the minute details helped me a lot to

acquire the insight into the subject.

I am also grateful to Mr. Eze Odike, also my trainer for giving best knowledge about

computer networks. The way he instilled knowledge of the subject was worthy and

valuable.

I am also thankful to JEFF Communication as a whole for their effort towards instilling

networking and hardware knowledge, that is the need of the day.

TABLE OF CONTENT1. Introduction…………………………………….

2. Abstract…………………………………………

3. Introduction to networking………………………

4. Categories of network…………………………..

5. IP address and MAC address……………………

6. Network Medias………………………………….

7. DNS Servers………………………………………

8. DHCP servers……………………………………..

9. Virtual private networks…………………………..

10. Routing……………………………………………..

11. Exchanger servers…………………………………..

12. OSI Model…………………………………………..

13. Routers………………………………………………

14. Conclusion……………………………………………

References…………………

INTRODUCTION

This project report pertains to 8weeks industrial training that I had underwent at

JEFF communication as part of curriculum of degree in Bachelor of technology in

computer science engineering as required by School of Engineering and technology,

Sharda University .

I learnt a lot from professional managers and skilled engineers. I had a great

learning experience as trainee in this firm. I learnt a lot about system maintenance,

Assembly and troubleshooting, how different networks are controlled in the industry or

any department with the help of networking processes, under MCSE and CCNA.

I have learnt about different type of servers like DHCP Server, DNS Server, NAT

Server. Also I have learnt how to control the LAN and MAN networks under MCSE

(Microsoft Certified System Engineers) and how to control MAN and WAN networks

under CCNA (CISCO Certified System Engineers).

ABSTRACT

Computer Networking is a very vast project in the present developing era of computer

science. Now a days, computers are used in a wider range. All the organizations are using

multiple computers within their departments to perform their day to day work. Computer

network allows the user to share data, share folders and files with other users connected

in a network. Computer Networking has bound the world in a very small area with it

wide networking processes like LAN, MAN, WAN.

NETWORKINGIntroduction to networking

Networking is a practice of linking of two or more computing devices

such as PCs, printers, faxes etc., with each other Connection between two devices is

through physical media or logical media to share information, data and resources.

Networks are made with the hardware and software.

Models of Networking

Model means the connectivity of two computers. We have many types of

networking models.

(i) Client – Server Model

(ii) Peer to Peer Model (Workgroup Model)

(iii) Domain Model

(i) Client –Server Model

In a Client server model we have one server and many clients. A Client can share

the resources of server, but a server cannot share the resources on clients.

On the point of view of administrator it’s very easy to control the network

because we combine with the server also at security point of view. It is very useful

because it uses user level security in which users have to remember only one password to

share the resources.

(ii) Peer to Peer Model (Workgroup Model)

In Peer to Peer networking model all computers are in equal status, that is we

cannot manage centralization, administration security. In Peer to Peer networking client

use operating system like Window 98, Window XP, Window 2000, Window Vista.

(iii) Domain Model

It is a mixture of client server and peer-to-peer model. In this clients can share

their resources as peer-to-peer but with the permission of the server as in client server

model therefore it is commonly used model because in this security is more as we can put

restriction on both server and clients.

Categories of networkNetworks can be categorized as per geographical area to be covered by the

network. Computer network are divided into four categories includes: Local Area

Network (LAN), Campus Area Network (CAN), Metropolitan Area Network (MAN) and

Wide Area Network (WAN).

Local Area Network (LAN)

LAN is a computer network that is used to connect computers and work station to

share data and resources such as printers or faxes. LAN is restricted to a small

area such as home, office or college. Devices used in LAN are : HUB and switch.

Media for LAN is UTP cables. Figure 1.2 shows how all work stations, server and

printer are interconnected with the help of the network device.

Campus Area Network (CAN)Campus Area Network is a computer network made up of two or more LANs

within a limited area. It can cover many buildings in an area. The main feature of

CAN is that all of the computers which are connected together have some

relationship to each other e.g. different buildings in a campus can be connected

using different CAN. It will help to interconnect academic departments, library

and computer laboratories. CAN is larger than LAN but smaller than WAN.

Metropolitan Area Network (MAN)MAN is the interconnection of networks in a city. MAN is not owned by a single

organization. It act as a high speed network to allow sharing resources with in a

city. MAN can also be formed by connecting remote LANs through telephone

lines or radio links. MAN supports data and voice transmission. The best example

of MAN is cable T.V network in a city.

Wide Area Network (WAN) WAN covers a wide geographical area which include multiple computers or

LANs. It connects computer networks through public networks like, telephone system,

microwave, satellite link or leased line.

Most of the WANs use leased lines for internet access as they provide faster data transfer.

WAN helps an organization to establish network between all its departments and offices

located in the same or different cities. It also enables communication between the

organization and rest world.

Devices used in WAN is only Router

IP ADDRESSES and MAC Addresses It is also called as logical addresses. IP is a 32 bit long and it is divided into 4

octets and dot (.) is used to separate one octet from another. It is represented in the

form of decimals. There are two versions of IP addresses:

- IPv4

IP Address ClassesIP address is a 32 bit address. It is divided into various classes namely Class A, Class

B, Class C, Class D and Class E. TCP/IP defines Class D for experimental purpose.

TCP /IP address contains two addresses embedded within one IP address; Network

address and host address as shown in figure 3.1

NETWORK

ADDRESS

HOST ADDRESS

0 bits 31 bits

Class A consists of 8-bit network ID and 24-bit host ID. Class B consists of 16-

bit network ID and 16-bit of host ID. And Class C consists of 24-bit of network

ID and 8-bit of host ID.

How to Assign IP Address to ComputerAn IP address assigned to a computer may either be permanent address or address

that is assigned to a computer on a time lease or for temporary basis. Hence, the address

granted to computers is divided into two categories Dynamic IP addresses and Static

addresses.

Dynamic IP AddressesDynamic IP addresses are assigned to the devices that require temporary

connectivity to the network or non-permanent devices such as portable computer. The

most common protocol used for assigning Dynamic IP address is DHCP also called

Dynamic Host Configuration Protocol. The DHCP grants IP address to the computer on

lease basis.

Static IP AddressesStatic IP addresses are assigned to the device on the network whose existence in

the network remains for a longer duration. These static IP addresses are semi-permanent

IP addresses which remain allocated to a specific device for longer time e.g. Server.

MAC Addressing

MAC address is a hardware address that is embedded in the NIC card. It is also known

as hardware address or physical address. Every NIC card has a unique MAC address

assigned by IEEE. MAC address is used to identify the nodes at lower levels of OSI

model. The MAC address operates at the data link layer of the OSI model.

MAC address is a 12 digit hexadecimal number (48 bit address). It is made up of

numbers from 0-9 or a letter from A-F. MAC address can be written in any one of the

formats:

MM:MM:MM:SS:SS:SS

MM:MM:MM:SS:SS:SS

NETWORKING MEDIATo do networking we need to use some type of media. There are many types of media.

(i) Coaxial Cable

(ii) Fiber optic cable

(iii) Twisted Pair of Cables

(iv) Micro- wave

(iv) Satellite

Coaxial Cable

Coaxial cable consists of an insulated copper conductor surrounded by a tube

shaped copper braid outer copper tune and the inner conductor have the same axis of

curvature hence it called coaxial cable. It is basically of two types:

(i) Base Band Cable (RG – 59)

(ii) Broad Band Cable (RG – 58)

We used Base Band signal cable in Networking of Computers, It is so called because

it carries single frequency. Its speed is 10 Mbps and impedance is 50 Ω. Where as Broad

Band Cables carries multiple frequencies. Connector used for Coaxial cable is

BNC(British Novel Connector) connector. ARCnet uses RG-62 coaxial cable. It has an

impedance of 93 Ω and has a comparatively lesser attenuation, hence yield greater

distances. These cables are expensive and provide high propagation factor.

Fiber Optical Cable

Fiber optic cable consists of a very fine fiber made from two types of glass, one for the

inner core and the other for the outer layer. Here signal is transmitted in the form of light.

Different varieties of fiber optics is used depending on the size of the network. Single

mode fiber optics is used for networks spanning longer distance. Fiber Optics has lower

propagation factor than coaxial cable. It is a costly but more secure transmission media.

Twisted Pair Cable

There are two wires, which are twisted with each other to avoid EMI (Electro

Magnetic Induction).these cables are easy to terminate. However they have a slightly

higher value of attenuation value and hence have limited distance covering capacity.

Connector used for Twisted Pair of Cable is (Registered Jack) RJ-45 and RJ-11. There

are two types of twisted pair of cables:

STP (Shielded Twisted Pair):

In this an extra wire which is called shielded wire is wrapped over the inner

cover which holds copper in pairs. This protection is used to protect signal from

external noise.

UTP (Unshielded Twisted Pair)

In this type of wire no shielded cover is there for extra protection from noise.

There are different categories of UTP cables:

Ethernet Cabling There are three types of Ethernet cables:

Straight cable

Crossover cable

Rolled cable

Straight cable It is used when we have to connect

PC TO Switch

PC to Hub

Hub to Router

Switch to Router

Crossover CableIt is used when we have to connect:

PC to PC

Hub to Hub

Switch to switch

Router to Router

PC to Router

Hub to Switch

Rollover CableRollover cable isn’t used to connect any Ethernet connections together, but

Rollover cable can be used to connect a host to a router console serial communication

(com) port.

NOTE: Straight cable and Cross cables are used for data transfer but Rollover

cables are not used for data transfer.

There are two methods for manufacturing Rollover cables:

DNS SERVER DNS stands for domain name system. DNS system is a standard technology

for managing the names of websites and other internet domains. DNS techniques allows

you to type names into your web browser like computer networking, about computer and

allow your computer to automatically find that address on internet. DNS is the resolution

mechanism used by Window Server 2003 clients to find other computers and services

running on those computers for computers in a window 2003 network infrastructure to

talk to one another, one of the key ingredients is the DNS server .Host name alone do not

communicate globally but communicate locally, but if domain name is added along with

it then the host name can communicate globally. DNS is use for name reservation i.e. to

convert IP address to host name and host name to IP address or the function of DNS is to

resolve host name such as www.yahoo.com to an IP address. User identify only user

friendly name and all computers and technologies identify IP address and MAC address

DNS is use to solve this problem because DNS is used to convert host name FQDN (fully

qualified domain name) to IP address and IP address to host name .

PARTS OF DNS SYSTEM (i) Host name

(ii) Domain name

(iii) FQDN

(iv) Namespace

(v) DNS server

HOST NAME Host name is a computer name and is also called is NetBIOS (network basic

Input/ output system) name. NetBIOS is actually an application layer protocol that can

use the transport services of TCP/ IP when used in routed network. A NetBIOS name is

16- byte addresses that identify a NetBIOS resource on the network.

DOMAIN NAME Domain name is used to identifies the internet site one can identifies the location

without having to remember the IP address of every location e.g. yahoo.com or

gmail.com

Domain NamespaceDNS operates in what is known as DNS namespace. The DNS namespace is an

organized, hierarchical division of DNS names. Domain namespace enable users to easily

locate the network services and resources. The domain namespace include the root

domain, the top level domain of the organization and organize these domain in a

hierarchical tree structure. Namespace works on the hierarchical tree structure of root

domain. There are total 13 root domain working in the internet, they are A, B, C, D, E, F,

G, H, I, J, K, L and M. There is one root domain, which acts as the starting point of the

fully qualified domain names. This root domain is designated with a dot (.). Fig 6.2

shows the tree structure or domain namespace.

Tree structure or Domain Namespace

DNS server

Any computer providing domain namespace is a DNS server. DNS server is used to

convert host name FQDN into IP address and IP address into host name FQDN. To store

the name-to-IP-addresses mappings so crucial to network communication, name server

uses zone files.

DNS Zone Zone is the part of DNS database that contain record of domain or multiple domain.

If the domains represents logical division of the DNS namespace, zones represents the

physical separation of the DNS namespace. In other words information about records of

the resources within DNS domain is stored in a zone files, and this zone files exist on

hard drive of server. Zone files are divided into one of two basic types:

Forward lookup zone: Provides host-name-to-IP-address resolution

Reverse lookup zone: Provides IP-address-to-host-name resolution

Resource record stored in a zone file Each record stored in a zone file has a specific purpose. Some of the records set the

behavior of the name server; others have the job of resolving a host name or service into

an IP table.

(i) NS (Name Server):

These specify the name servers that are authoritative for a given portion

of DNS namespace. These records are essential when DNS servers are performing

iterative queries to perform name resolution.

(ii) SOA (Start of Authority):

This resource record indicates the name of origin for the zone contains the name

of the server that is the primary source for information about the zone. The information in

an SOA record affect how often transfer of the zone are done between servers

authoritative for the zone. It is also used to store other properties such as version

information and timings that affect zone renewal or expiration.

(iii) CNAME (Canonical Name):

CNAME can be used to assign multiple names of a single IP address.

For example, the server hosting the site www.abc.com is probably not named www, but a

CNAME record exist resolution of www to an IP address all the same. The CNAME

record actually points not to an IP address, but to an existing A record in the zone.

DHCP SERVER

DHCP (Dynamic Host Configuration Protocol) is a protocol that allocates IP address to

computer on a network. DHCP centralized the management of IP address allocation and

reduces human error associated with manual IP configuration. DHCP server supplies all

the necessary networking parameters. Two things are always handed out as a part of

DHCP configuration: IP address and subnet mask. Further DHCP will frequently

configure clients with optional values, such as a default gateway, DNS server address,

and the address of a Window Internet Naming Server, if one is present. Scenario showing

DHCP server IP addresses allocation.

Working of DHCP Server(i) DHCP Scope

(ii) DHCP Super Scope

(iii) Exclusion IP Range

(iv) DHCP Lease Time

(v) IP Reservation

DHCP Scope

Scope having the range of IP address for providing dynamic IP address to other

computer. A group of IP address within a scope is called as DHCP scope.

DHCP Super Scope

A super scope is used to combine two or more scopes each serving different subnets, and

can make the administration of several scopes on window 2003 DHCP server more

manageable. Using super scope you can group multiple scopes as a single administrative

entity that allows the client to lease from either one. With this feature, a DHCP server

can:

Support DHCP clients on a single physical network segment where multiple

logical IP networks are used. When more than one logical IP network is used on

each physical subnet or network, such configuration is called multinets.

Support DHCP clients located on the far side of DHCP and BOOTP relay agent.

In multinet configuration, DHCP super scope can be used to group and activate

individual scope ranges of IP addresses used on your network. In this way , a

DHCP server computer can activate and provide leases from more than one scope

to clients on a single physical network.

Exclusion IP range

If you want to reserve some IP for any computer i.e. if we want that from the series of

192.168.0.2 to 192.168.0.100 if we want that a series of IP addresses must not be

assigned automatically then at can be done using exclusive IP range.

IP Reservation

There are some DHCP clients that you want to be the DHCP clients, but you will also

want to make sure that they get same IP address every time. This can be done by

statically filling the IP address. We can reserve IP address with the help of MAC address

for a particular computer.

VIRTUAL PRIVATE NETWORK (VPN) A virtual private network is used to convert public network address to private

network. All the clients of VPN dial to public IP address of VPN server and receive

private IP from virtual VPN dynamic host protocol (DHCP).in VPN one can have

multiple virtual connections to a single IP address. This way ,one network card can host

several inbound connections, rather than require a modem and telephone line for each

simultaneous remote user.

Using VPN server we can connect many private networks to internet services i.e the

remote connection. We can create a private network through public network, we can use

firewall for security and data encryption in VPN server.

VPN components(i) VPN server

(ii) VPN Clients

(iii) WAN Option

(iv) Security Options

VPN Server

VPN server, serve as the end points of a VPN connection. When configuring a

VPN server, you can allow access to just that server, or pass traffic through VPN server

so that the remote user gain access the resources of the entire network.

VPN Client

VPN clients establish connection to VPN server. They can also be routers that

obtain the router-to-router secure connection. VPN client software is included in all the

modern window operating systems, including Window 2003 server. Router-to router

VPN connection can be made from computers running server2003 and Windows 2000

running Routing and Remote Access. Additionally, any client that support PPTP or

L2TP connections can be VPN clients of a window server 2003 system.

WAN Options

These provide the physical mechanism for passing data back and forth. These

connections typically include such similar network technologies such as T1or frame

relay. In order for VPN connections to be successful, the VPN client and VPN server

must be connected to each other using either permanent WAN connection or by dialing

into an internet server provider (ISP).

Security Options

Since a VPN uses a network that is generally open to the public, it is important

that the data passed over the connection remain secure. To aid with secure

communication routing and remote access supports such security measure as logon and

domain security, data encryption, smart cards, IP packet filtering and caller ID.

Types of VPN(i) PPTP (Point to Point Tunneling Protocol )

(ii) L2TP (Layer 2 Tunneling Protocol) according to CCNA.

Point to Point Tunneling Protocol (PPTP)

PPTP is Microsoft’s legacy protocol for supporting VPN. It was developed in

conjunction with other communications companies such as Robotics as an extension to

the PPP protocol. PPTP encapsulates IP or IPX packets inside of PPP datagram’s. This

means that you can remotely run programs that are dependent upon particular network

protocols. One of the keys to remember about PPTP is that the protocol provides

encryption capabilities, making it much safer to send information over nonsecure

networks.

Layer Two Tunneling Protocol (L2TP)

L2TP is a standard based encapsulation protocol with roughly the same

functionality as a Point-to-Point Tunneling Protocol (PPTP). One of the key differences

between Window’s server 2003 implementation of L2TPand it cousin PPTP is that

L2TPis designed to run natively over IP networks only. This implementation of L2TP

does not support native tunneling over X.25, frame relay, or ATM networks. Like PPTP,

L2TPencapsulates Point-to-Point Protocol (PPP) frames, which then encapsulate IP or

IPX protocols, allowing users to remotely run programs that are dependent on specific

network protocols . But unlike the PPTP protocol, L2TP does not provide encryption of

the data. For data security L2TPrelies on the services of another standards- based

protocol, IPSec.

ROUTINGIt is a process of transferring information through an inter network i.e from one

network to another. Routing connect different networks having ID help in process of

routing. The dial-in properties also allow for specific IP address to be assigned to a user.

This is the only way in Window Server 2003 that you can assign a specific IP to a user.

To assign a specific IP to a user, check the box next to assign A Static IP Address and

enter a valid IP in the space provided. Static routing can also be specified as per user. By

defining static routes, users can be limited to only specific parts of networks.

In an internetwork a router must then about all the networks present in the for

effort websites, there are hardware routers like CISCO. Even win 2003 server computer

configured as router. In simple words Router is a computer with two network cards.

These two network cards, then, are attached to two different logical IP networks. The

routing table helps direct traffic that is passed through the router.

Now when there is a router, also there is a routing table, there is a need to

configure the router in order for that router to pass along traffic to the proper network.

There are two ways the routing table can be built and modified: either manually or

automatically.

3.9.1 Types of Routing(i) Static Routing

(ii) Dynamic Routing

Static Routing In this routing information required for routing is manually entered into the router

by administrator.

How to configure LAN routing Enter the static IP in the router

Administrator tools

Routing and Remote access

Right click on computer name (pcc1)

Configure and enable routing and remote access

next→ custom configuration

select LAN routing→next→ finish

yes and logon to see IP table route

Enable LAN routing enable LAN routingInterface WAN Interface WAN 10.0.0.0IP 172.15.0.0 IP 10.0.0.0SNM 255.255.0.0 SNM 255.0.0.0GW 20.0.0.2 GW 20.0.0.1

Fig 16 : scenario for LAN routing

How to configure static routing

At Router R1:

enable LAN routing

right click on static route

interface WAN

destination 172.15.0.0

mask 255.255.0.0

GW 20.0.0.2

At Router R2:

Enable LAN routing

Right click on static route

Interface WAN

Destination 10.0.0.0

Mask 255.0.0.0

GW 20.0.0.1

Fig 17 : static routing

3.10.1.2 Dynamic Routing

The other way to manage a router routing tables is to let the computer do it

for you. Just like DHCP allocate IP addresses, configuring the dynamic routing

protocol usually means less errors due to human error, and less administrative

overhead.

In dynamic routing, routing information is automatically entered in the

router using protocols like RIP AND OSPF. These routing protocols used by

Window Server 2003 use one of two kinds of algorithms to determine the best

possible path for a packet to get to its destination, either distance vector or link

state. RIP is used for small networks where as OSPF is used for large networks.

Routing Information Protocol (RIP)The distance vector protocol in use on Window 2003 is called Routing

Information Protocol (RIP) for IP. This protocol was designed for the exchange of

the routing information within a small to medium size IP network.

When Router is enabled on Window 2003 machine, the routing table includes

entries only for the networks that are physically connected. When RIP is enabled

for an interface, the router will periodically send an announcement of its routing

table to inform other RIP routers of the networks it can reach. RIP version1 uses

broadcast packets for its announcement. RIP version2 offers an improvement and

can be configured to use either multicast or broadcast packets when

communicating with other routers. Also, RIP version2 offers more flexibility in

subnetted and classless inter domain routing (CIDR) environments.

Open Shortest Path First (OSPF)

Where RIP is built to work to work in smaller networks, the Open Shortest Path

First (OSPF) routing protocol is designed for large or very large networks. The goal is the

same: information about connection to other networks is shared from one router to

another. It offers several advantages over RIP, especially significant in large networks:

EXCHANGE SERVERExchange server is a mail server, we can send and receive mail from one user to another

user. Exchange server is the mail server of Microsoft.

Elements of Exchange Server Mail Server

A server which helps to the users to send and receive mail is called mail server.

Mail Box

A storage place where senders and receivers mails are stored.

Exchange Version Table 10: Exchange Server with different operating systems

Where SP stands for Service Pack. Service Pack are the services which are loaded

externally to remove some bugs that come during installation of server CD.

Requirements for Exchange Server

Protocols Required POP3 (Post Office Protocol)

This protocol is used for receiving e- mails.

IMAE4 (Internet Messaging Access Protocol)

This protocol is advance version of POP, this is also used to receive mail.

LMTP (Local Mail Transfer Protocol)/SMTP (Simple Mail Transfer Protocol)

This protocol is used to send mails.

NNTP (Network News Transfer protocol)

This protocol is used for transferring messages on internet.

Hardware Requirements Processor: min. 133MHz Rec. 733MHz

RAM: min. 256MB Rec. 512MB

Other Requirements OS: 2k or 2k3 Server

NTFS partition

Static IP address

Active Directory

DNS installation with AD zone

IIS installed with ASP.net, SMTP, NNTP and www service

Open System Interconnection (OSI) ModelOSI model is the layer approach to design, develop and implement network. OSI

provides following advantages: -

(i) Development of new technology will be faster.

(ii) Devices from multiple vendors can communicate with each other.

(iii) Implementation and troubleshooting of network will be easy.

Description of Different LayersApplication Layer

Application layer accepts data and forward into the protocol stack. It creates user

interface between application software and protocol stack.

Presentation Layer

This layer decides presentation format of the data. It also able to performs other

function like compression/decompression and encryption/decryption.

Session Layer

This layer initiate, maintain and terminate sessions between different applications.

Due to this layer multiple application software can be executed at the same time.

Transport Layer

Transport layer is responsible for connection oriented and connection less

communication. Transport layer also performs other functions like

(i) Error checking

(ii) Flow Control

Buffering

Windowing

Multiplexing

(iii) Sequencing

(iv) Positive Acknowledgement

(v) Response

(vi)

Network Layer

This layer performs function like logical addressing and path

determination. Each networking device has a physical address that is MAC

address. But logical addressing is easier to communicate on large size network.

Logical addressing defines network address and host address. This type of

addressing is used to simplify implementation of large network. Some

examples of logical addressing are: - IP addresses, IPX addresses etc.

Network layer has different routing protocols like RIP, EIGRP, BGP, and

ARP etc. to perform the path determination for different routing protocol.

Network layer also perform other responsibilities like defining quality of service,

fragmentation and protocol identification.

Data Link Layer

The functions of Data Link layer are divided into two sub layers

Logical Link Control

Media Access Control

(i) Logical Link Control defines the encapsulation that will be used by the

NIC to delivered data to destination. Some examples of Logical Link

Control are ARPA (Ethernet), 802.11 wi-fi.

(ii) Media Access Control defines methods to access the shared media and

establish the identity with the help of MAC address. Some examples of

Media Access Control are CSMA/CD, Token Passing.

Physical Layer

Physical Layer is responsible to communicate bits over the media this

layer deals with the standard defined for media and signals. This layer may also perform

modulation and demodulation as required.

ROUTERS

Router Architecture and its Key Component

Incomplete IOS

IOS

Startup Configuration

Processor

Memory Controller

BIOS ROM

NVRAM

RAM

Flash RAM O/S

I/O Controller

LAN

WAN

Ports

Router Interfaces & Ports Interface is used to connect LAN networks or wan networks to the router.

Interface will use protocol stacks to send/receive data. Ports are used for the

configuration of routers. Ports are not used to connect different networks. The primary

purpose of port is the management of router.

Router interfaces and connectors

AUI – Attachment Unit Interface

EPABX – Electronic Private Automatic Branch

PSTN – Public Services Telephone Network

3.13.2.2 Router Ports

Table 12: Router Ports

Modes of RouterWhen we access router command prompt the router will display different modes.

According to the modes, privileges and rights are assigned to the user.

User mode Router>

In this mode, we can display basic parameter and status of the router we can test

connectivity and perform telnet to other devices. In this mode we are not able to change

and save router configuration.

Privileged mode Router#

In this mode, we can display all information, configuration, perform administration task,

debugging, testing and connectivity with other devices. We are not able to perform here

configuration editing of the router.

The command to enter in this mode is ‘enable’. We have to enter enable

password or enable secret password to enter in this mode. Enable secret has more priority

than enable password. If both passwords are configured then only enable secret will

work.

Global configuration Route(config)#

This mode is used for the configuration of global parameters in the router. Global

parameters applied to the entire router. All the changes are performed in this mode. But

here we cannot see and save the changes.

For e.g: - router hostname or access list of router, password, Banner, Routing, Security.

The command to enter in this mode is ‘configure terminal’

Line configuration modeIn this mode we can set the password of the user mode, i.e to set user mode

password .This mode is used to configure lines like console, vty and auxiliary. There are

main types of line that are configured.

(i) Console

Router(config)#line console 0

(ii) Auxiliary

Router(config)#line aux 0

(iii) Telnet or vty

Router(config)#line vty 0 4

Interface configuration modeIn this mode we can set ip addresses of the interfaces. This mode is used to

configure router interfaces. For e.g:- Ethernet, Serial, BRI etc.

Router(config)#interface <type> <number>

Router(config)#interface serial 1

Routing configuration mode

This mode is used to configure routing protocol like RIP, EIGRP, OSPF etc.

Router(config)#router <protocol> [<option>]

Router(config)#router rip

Router(config)#router eigrp 10

Configuring Password There are five types of password available in a router

Console Password router#configure terminal

router(config)#line console 0

router(config-line)#password <word>

router(config-line)#login

router(config-line)#exit

To erase password do all steps with no command.

Vty Passwordrouter>enable

router#configure terminal

router(config)#line vty 0 4

router(config-line)#password <word>

router(config-line)#login

router(config-line)#exit

Auxiliary Passwordrouter#configure terminal

router(config)#line Aux 0

router(config-line)#password <word>

router(config-line)#login

router(config-line)#exit

Enable Passwordrouter>enable

router#configure terminal

router(config)#enable password <word>

router(config)#exit

Enable Secret PasswordEnable Password is the clear text password. It is stored as clear text in

configuration where as enable secret password is the encrypted password.

Router>enable

Router#configure terminal

Router(config)#enable secret <word>

Router(config)#exit

Encryption all passwordsAll passwords other than enable secret password are clear text password. The

command to encrypt all password are

Router#configure terminal

Router(config)#service password-encryption

Managing ConfigurationThere are two types of configuration present in a router

(i) Startup Configuration

(ii) Running Configuration

Startup configuration is stored in the NVRAM. Startup configuration is used to

save settings in a router. Startup configuration is loaded at the time of booting in to the

Primary RAM.

Running Configuration is present in the Primary RAM wherever we run a

command for configuration, this command is written in the running configuration.

To save configurationRouter#copy running-configuration startup-configuration

Or

Router#write

To abort configurationRouter#copy startup-configuration running-configuration

To display running-configurationRouter#show running-configuration

To display startup configurationRouter#show startup-configuration

Configuring Host NameRouter#configure terminal

Router(config)#hostname <name>

<name>#exit or end or /\z

Router#config terminal

Router(config)#hostname r1

R1(config)#

Configuration InterfacesInterfaces configuration is one of the most important part of the router

configuration. By default, all interfaces of Cisco router are in disabled mode. We have to

use different commands as our requirement to enable and configure the interface.

Router#configure terminal

Router(config)#interface <type> <no>

Router(config-if)#ip address <ip> <mask>

Router(config-if)#no shutdown

Router(config-if)#exit

To display interface status

Router#show interfaces (to show all interfaces)

Router#show interface <type> <no>

This command will display following parameters about an interface

(1) Status

(2) Mac address

(3) IP address

(4) Subnet mask

(5) Hardware type / manufacturer

(6) Bandwidth

(7) Reliability

(8) Delay

(9) Load ( Tx load Rx load)

(10) Encapsulation

(11) ARP type (if applicable)

(12) Keep alive

Configuring optional parameter on WAN interface Router#configure terminal

Router(config)#interfac <type> <no>

Router(config-if)#encapsulation <protocol>

Router(config-if)#clock rate <value>

Router(config-if)#end

Command displaying history of Router

To display commands present in historyRouter#show history

To display history sizeRouter#show terminal

To change history sizeRouter#config terminal

Router(config)#line console 0

Router(config-if)#history size <value(0-256)>

Router(config-if)#exit

To set time in routerWe can configure router clock with the help of two methods:

(i) Configure clock locally

(ii) Configure clock on NTP server (Network Time Protocol)

Router does not have battery to save the clock setting. So that clock will reset to the

default on reboot.

To display clockRouter#show clock

To configure clockRouter#clock set hh:mm:ss day month year

Router#clock set 7:15:10 9 June 2009

To configure clock from NTP serverRouter#config terminal

Router(config)#ntp server <IP address>

Router(config)#exit

C:\>ping pool.ntp.org

To get ntp server ip from internet

C:\>route print

ROUTING

Routing is a process or technique to identify the path from one network to

another. Routers don’t really care about hosts—they only care about networks and the

best path to each network.

To route the packet the router must know the following things:

Destination network

Neighbour device from witch it can learn about remote Networking.

Possible number of routers to reach the destination.

Best route to reach the destination.

How to maintain & verify the routing information.

TYPES OF ROUTING Static routing.

Default routing.

Dynamic routing.

STATIC ROUTING In static routing an administrator specifies all the routes to reach the destination.

Static routing occurs when you manually add routes in each router’s routing table.By default,

Static routes have an Administrative Distance (AD) of 1

Features There is no overhead on the router CPU.

There is no bandwidth usage between routers.

It adds security, because the administrator can choose to allow routing access to certain

networks only.

Syntax for Static Routing

Router (config)# ip route <destination N/w> <Subnet mask> <Next

Hope- address or exit interface> [<administrative distance>Permanent].

Static routing of router (R1)Router(config)#ip route 20.0.0.0 255.0.0.0 40.0.0.2

Router(config)#ip route 30.0.0.0 255.0.0.0 40.0.0.2

Router(config)#ip route 50.0.0.0 255.0.0.0 40.0.0.2

Router(config)#interface so/1/0

Router(config)# clock rate 64000

Router # show ip route

Static routing of router (R2) Router(config)#ip route 10.0.0.0 255.0.0.0 40.0.0.1

Router(config)#ip route 30.0.0.0 255.0.0.0 50.0.0.2

Router#show ip route

Router(config)#interface s1/0

Router(config)# clock rate 64000

Router(config)#interface s1/1

Router(config)#clock rate 64000

Router#show ip route

Static routing of router (R3) Router(config)#ip route 10.0.0.0 255.0.0.0 50.0.0.1

Router(config)#ip route 20.0.0.0 255.0.0.0 50.0.0.1

Router(config)#ip route 40.0.0.0 255.0.0.0 50.0.0.1

Router(config)#interface s1/0

Router(config)# clock rate 64000

Router#show ip route

DYNAMIC ROUTING Dynamic routing is when protocols are used to find networks and update

routing table on routers.

A routing protocol defines the set of rules used by router when it communicates

routing information between neighbor routers. In dynamic routing, we will enable a

routing protocol on router. This protocol will send its routing information to the neighbor

router. The neighbors will analyze the information and write new routes to the routing

table.

The routers will pass routing information receive from one router to other

router also. If there is more than one path available then routes are compared and best

path is selected. Some examples of dynamic protocol are: -

RIP, IGRP, EIGRP, OSPF

There are two type of routing protocols used in internetworks:

Interior Gateway Protocols (IGPs)IGPs are used to exchange routing information with routers in the same

Autonomous System(AS) number. Routing which is performed within a single

autonomous system is known as interior routing. The protocol that are used to perform

this type of routing are known as IGP(Interior Gateway Protocol).

These protocols are:-

(i) RIPv1 (Routing Information Protocol Version 1)

(ii) RIPv2 (Routing Information Protocol Version 2)

(iii) EIGRP (Enhanced Interior Gateway Routing Protocol)

(iv) OSPF (Open Shortest Path First)

(v) IS-IS (Intermediate System to Intermediate System)

Exterior Gateway Protocols (EGPs)EGPs are used to communicate between different Autonomous System.

Protocol that used to do this type of routing are called exterior gateway protocols.

Autonomous System:- An autonomous system is a collection of networks under a

common administrative domain, which basically means that all routers sharing the same

routing table information are in the same AS.

Routing Protocol Basics(i) Administrative Distances

(ii) Routing protocol

(iii) Routing Loops

Administrative Distances

The Administrative Distance (AD) is used to rate the trustworthiness of routing

information received on a router from a neighbor router. An Administrative Distance is

an integer from 0 to 255, where 0 is the most trusted and 255 means no traffic will be

passed via this route.

If a router receives two updates listing he sane remote network, the first thing the router

checks is the AD. If one of the advertised routes has lower AD than the other, then the

route with the lowest AD will be placed in the routing table. If both advertised routes to

the same network have the same AD, then routing protocol metrics (such as hop count or

bandwidth of the lines) will be used to find the best path to the remote network. The

Advertised route with the lowest metric will be placed in the routing table.

But if both advertised routes have the same AD as well as the same metrics, then the

routing protocol will load-balance in the remote network.

Route Source Default AD

Connected interface 0

Static Route 1

EIGRP 90

IGRP 100

OSPF 110

RIP 120

External EIGRP 170

Unknown 255 This route will never be used

IGRP (Interior Gateway Protocol)Interior Gateway Routing Protocol (IGRP) is a Cisco-proprietary distance-vector

routing protocol. To use IGRP, all your routers must be Cisco routers. IGRP has a

maximum hop count of 255 with a default of 100. IGRP uses bandwidth and delay of the

line by default as a metric for determining the best route to an internetwork. Reliability,

load, and maximum transmission unit (MTU) can also be used, although they are not

used by default.

EIGRP (Enhanced Interior Routing Protocol)Enhanced IGRP (EIGRP) is a classless, enhanced distance-vector protocol

that gives us a real edge over IGRP. Like IGRP, EIGRP uses the concept of an

autonomous system to describe the set of contiguous routers that run the same routing

protocol and share routing information. But unlike IGRP, EIGRP includes the subnet

mask in its route updates. The advertisement of subnet information allows us to use

VLSM and summarization when designing our networks.

EIGRP is sometimes referred to as a hybrid routing protocol because it has

characteristics of both distance-vector and link-state protocols. It sends traditional

distance-vector updates containing information about networks plus the cost of

reaching them from the perspective of the adverting router. EIGRP has a maximum

hop count of 255.

OSPF (Open Shortest Path First)Open Shortest Path First (OSPF) is an open standards routing protocol that’s been

implemented by a wide variety of network vendors, including Cisco. This works by using

the Dijkstra algorithm. First, a shortest path tree is constructed, and then the routing table

is populated with the resulting best paths. OSPF converges quickly, although perhaps not

as quickly as EIGRP, and it supports multiple, equal-cost routes to the same destination.

But unlike EIGRP, it only supports IP routing.

OSPF is an IGP protocol. It is a link state routing protocol. It is supported by

many operating systems. Its default AD is 110, hop count limit is unlimited.

It is classless routing protocol, supports VLSM/CIDR. By default the highest IP address

of interface will be elected as Router id.

Broadcast (multi-access)

Broadcast (multi-access) networks such as Ethernet allow multiple devices to

connect to (or access) the same network, as well as provide a broadcast ability in which a

single packet is delivered to all nodes on the network. In OSPF, a DR and a BDR must be

elected for each broadcast multi-access network.

Non-broadcast multi-access

Non-Broadcast Multi-Access (NBMA) networks are types such as Frame Relay,

X.25, and Asynchronous Transfer Mode (ATM). These networks allow for multi-access,

but have no broadcast ability like Ethernet. So, NBMA networks require special OSPF

configuration to function properly and neighbor relationships must be defined.

Point-to-point

Point-to-point refers to a type of network topology consisting of a direct

connection between two routers that provides a single communication path. The point-to-

point connection can be physical, as in a serial cable directly connecting two routers, or it

can be logical.

Point-to-multipoint

Point-to-multipoint refers to a type of network topology consisting of a series of

connections between a single interface on one router and multiple destination routers. All

of the interfaces on all of the routers sharing the point-to-multipoint connection belong to

the same network. As with point-to-point, no DRs or BDRs are needed.

CONCLUSIONComputer Networking is a very vast project in the present developing era of

electronics and communication. Now a days, computers are used in a wider range. All the

organizations are using multiple computers within their departments to perform their day

to day work. Computer network allows the user to share data, share folders and files with

other users connected in a network. Computer Networking has bound the world in a very

small area with it wide networking processes like LAN, MAN, WAN.

Applications Communication Field

Industries

Medical Field

Research Field

Organizations

School

Colleges

REFRENCES www.goole.com

www.microsoft.com

www.nythimes.com

www.digitech-engineers.com

Network Essentials module

4-in-1 MCSE study material

Introduction to Window Server2003

CISCO Cretified Network Associate

Faruk Husain