Ccna report

PROJECT REPORT

ON

COMPUTER NETWORKING

AT

Guida IIHT Chandigarh

Under Guidance ofMr. Sanjay SIngh

Prepared BySurender SinghB. Tech. ECE5th SemRoll No 2511078

Summer Training Report On Computer Networking

TABLE OF CONTENT

1. Introduction to NetworkingDefinitionRequirement of Networking

2. Types of NetworkLAN (Local Area Network)WAN (Wide Area Network)

3. Network ModelsOSI Model

4. CablesTwisted CableCoaxial CableFibre Optic

5. Networking DevicesNetwork Interface CardHubSwitchRouter

6. IP AddressingIntroductionPrivate IPMaskingSubnettingExample

7. LAN SolutionRequirementSolutionSpecification Sheet


8. RouterInternal ComponentsNetwork InterfacesConfiguringConfiguring using ConsoleRouting Protocols

RIPIGRPAccess List

9. FirewallIntroductionTechnologiesConfiguring

10. WLANStandardsTopologiesInfrastructure NetworkAdhoc Network

11. Intrusion Detection System (IDS)HIDSNIDSTechniques

12. Integrated Services Digital Network (ISDN)ChannelsInterfacesFunctional GroupReference Points


INTRODUCTION TO NETWORKING

Definition :-

A network is a system that transmits any combination of voice, video and/or databetween users. A network can be defined by its geographical dimensions and bywhich the user’s PC access it.

A network consists of a: The network operating system (Windows NT/2000TM/Xp) on the user’s

PC (client) and server. The cables connecting all network devices (user’s PC, server,

peripherals, etc.). All supporting network components (hubs, routers and switches, etc.).

Computer Network means an interconnected collection ofautonomous computers.

Requirement of NetworkingResource sharing- To make all programs, equipment, and especially dataavailable to anyone on the network without regard to the physical location of theresource and the user.

High reliability- As all files could be replicated on two or three machines, so ifone of them is unavailable (due to hardware failure), the other copies could beused.

Scalability- It is the ability to increase system performance gradually as theworkload grows just by adding more processors.A computer network can provide a powerful communication medium alongwidely separated employees.

The use of networks to enhance human-to-human communication will probablyprove more important than technical goals such as improved reliability.

These are the requirement with respect to companies but computer networking isrequired even in the normal day to day life as we have to access the internet toget information about what all new happening in the world, to havecommunication with people staying far away using the e mail service.

These are the reasons that forced the inventerors to invent the networkingdevices, models and protocols etc.

And the birth of Networking took place in 1844 when for the firsttime Samuel Morse send the first telegraph message.


TYPES OF NETWORKS

LAN (LOCAL AREA NETWORK)

These are privately owned networks within a single building or campus of up to afew a kilometers in size.LAN’s are distinguished from other networks by three characteristics:1) Their size.2) Their transmission technology.3) Their topology.

LAN’s are restricted in size, which means that the worst-case transmission timeis bounded and known in advance.LAN’s often use a transmission technology consisting of a single cable to whichall the machines are attached.LANs run at speeds of 10 to 100 Mbps, have low delays, and make very fewerrors.

LAN SETUP

IEEE has produced several standards for LANs. These standards collectivelyknown as IEEE 802 .IEEE802.3 (Ethernet), IEEE802.4 (Token Bus), IEEE802.5 (Token Ring)


WAN (WIDE AREA NETWORK)

It is a Computer network that spans a relatively large geographical area, often acountry or continent. Typically a WAN consists of two or more Local AreaNetwork.Computers connected to WAN are often connected through public networks suchas telephone systems. They can also be connected through leased lines orsatellites. The largest WAN in existence is Internet.WANs run at speed of maximum 2 to 10 Mbps.

WAN SETUP

For most WANs, the long distance bandwidth is relatively slow: on the order ofkilobits per second (kbps) as opposed to megabits per second (Mbps) forlocal-area networks (LANs). For example, an Ethernet LAN has a 10 Mbpsbandwidth; a WAN using part or all of a T1 carrier has a bandwidth of 1.544Mbps .

Three types of approaches are used to connect WANs:

1) Circuit switching, which provides a fixed connection (at least for the duration ofa call or session), so that each packet takes the same path. Examples of thisapproach include ISDN, Switched 56, and Switched T1.

2) Packet switching, which establishes connections during the transmissionprocess so that different packets from the same transmission may take differentroutes and may arrive out of sequence at the destination. Examplesof this approach are X.25, frame relay, and ATM.

3) Leased lines, which can provide a dedicated connection for private use


NETWORK MODELS

Layering Concepts and Benefits

Many benefits can be gained from the process of breaking up the functions ortasks of networking into smaller chunks, called layers, and defining standardinterfaces between these layers. The layers break a large, complex set ofconcepts and protocols into smaller pieces, making it easier to talk about, toimplement with hardware and software, and to troubleshoot.The following list summarizes the benefits of layered protocol Specifications:

Humans can more easily discuss and learn about the many details of a protocolspecification.

Standardized interfaces among layers facilitate modular engineering.

A better environment for interoperability is created. One vendor can writesoftware that implements higher layers—for example, a Web browser—andanother can write software that implements the lower layers—for example,Microsoft’s built-in TCP/IP software in its operating systems.

Reduced complexity allows easier program changes and faster productevolution.

One layer uses the services of the layer immediately below it. Therefore,remembering what each layer does is easier. (For example, the network layerneeds to deliver data from end to end. To do this, it uses data links to forwarddata to the next successive device along that end-to-end path.)


OSI NETWORK MODEL

The OSI model describes how information makes its way from applicationprograms through a network medium to another application program in othercomputer. It divides one big problem in to seven smaller problems . Eachproblem is addressed by one of the seven layers of the OSI model.

Functions of Network Layers in Brief:

APPLICATION LAYER

Used for applications specifically written to run over the networkAllows access to network services that support applications;Directly represents the services that directly support user applicationsHandles network access, flow control and error recoveryExample apps are file transfer, e-mail, Net BIOS-based applications

PRESENTATION LAYER


Translates from application to network format and vice-versaAll different formats from all sources are made into a common uniformformat that the rest of the OSI model can understandResponsible for protocol conversion, character conversion, dataencryption / decryption, expanding graphics commands, data compressionSets standards for different systems to provide seamless communicationfrom multiple protocol stacksNot always implemented in a network protocol

SESSION LAYER

Establishes, maintains and ends sessions across the networkResponsible for name recognition (identification) so only the designatedparties can participate in the sessionProvides synchronization services by planning check points in the datastream => if session fails, only data after the most recent checkpoint needbe transmittedManages who can transmit data at a certain time and for how longExamples are interactive login and file transfer connections, the sessionwould connect and re-connect if there was an interruption; recognizenames in sessions and register names in history

TRANSPORT LAYER

Additional connection below the session layerManages the flow control of data between parties across the networkDivides streams of data into chunks or packets; the transport layer of thereceiving computer reassembles the message from packets"Train" is a good analogy => the data is divided into identical unitsProvides error-checking to guarantee error-free data delivery, with onlosses or duplicationsProvides acknowledgment of successful transmissions; requestsretransmission if some packets don’t arrive error-freeProvides flow control and error-handlingTCP, ARP, RARP;

NETWORK LAYER

Translates logical network address and names to their physical address(e.g. computer name ==> MAC address)

Responsible for addressing and determining routes for sending Managing network problems such as packet switching, data congestion

and routing


If router can’t send data frame as large as the source computer sends, thenetwork layer compensates by breaking the data into smaller units. At thereceiving end, the network layer reassembles the dataThink of this layer stamping the addresses on each train carIP; ARP; RARP, ICMP; RIP; OSFP;

DATA LINK LAYER

Turns packets into raw bits 100101 and at the receiving end turns bits intopackets.Handles data frames between the Network and Physical layersThe receiving end packages raw data from the Physical layer into dataframes for delivery to the Network layerResponsible for error-free transfer of frames to other computer via thePhysical LayerThis layer defines the methods used to transmit and receive data on thenetwork. It consists of the wiring, the devices use to connect the NIC tothe wiring, the signaling involved to transmit / receive data and the abilityto detect signaling errors on the network media

Logical Link Control

Error correction and flow controlManages link control and defines SAPs

PHYSICAL LAYER

Transmits raw bit stream over physical cableDefines cables, cards, and physical aspectsDefines NIC attachments to hardware, how cable is attached to NICDefines techniques to transfer bit stream to cable

IP ADDRESSING

Every machine on the internet has a unique identifying number, called an IPAddress. A typical; IP address looks like this:216.27.61.45

IP ADDRESS is a 32-bit number, usually written in dotted decimal form, thatuniquely identifies an interface of some computer. This 32-bit number is dividedinto 4 octets each separated by a decimal. Out so many values certain values


are restricted for use as typical IP address. For example, the IP address 0.0.0.0is reserved for the default network and the address 255.255.255.255is used forbroadcast.

Each IP address is split into 2 sections:

1) Network address

2) Host address

Individual IP address in same network all have a different value in the host part ofaddress, but they have identical value in network part, just as in town there aredifferent street address but same ZIP code.

There are five IP classes:

Class A – This class is for very large networks, such as a major internationalcompany. IP addresses with a first octet from 1 to 126 are part of this class. Theother three octets are each used to identify each host.

Net

54.

Host or Node

24.54.43

Loopback- The IP address 127.0.0.1 is used as the loopback address. Thismeans that it is used by the host computer to send a message back to itself. It iscommonly used for troubleshooting and network testing.

Class B- Class B is used for medium-sized networks. A good example is a largecollege campus. IP addresses with a first octet from 128 to191 are part of thisclass. Class B addresses also include the second octet as part of the Netidentifier. The other two octets are used to identify each host.

Net

145.24

Host or Node

53.198

Class C- Class C addresses are commonly used for small to mid-size business.IP addresses with a first octet from192 to 223 are part of this class. Class Caddresses also include the second and third octets as part of Net identifier. Thelast octet is used to identify each host.

Net

196.54.34

Host or Node

86

Class D- It is used for multicast. It has first bit value of 1, second bit value of 1,third bit value of 1 and fourth bit value of 0. The other 28 bits are used to identifythe group of computers the multicast messages is intended for.


Net

224

Class E- It is used for experimental purpose only.

Net

240.

Host or Node

24.54.145

Host or Node

23.45.105

Private IPIt is not necessary that every time we make a network we are connected to someISP (Internet Service Provider). So in that case we require some private IP alsowhich can be used in indigenous networks .In each class a range of IPaddresses have been defined for this purpose

CLASS A

CLASS B

CLASS C

10.0.0.1 to 10.255.255.244

172.16.0.1 to 172.34.255.254

192.168.0.0/16

MASKINGComputers use a mask to define size of network and host part of an address.Mask is a 32-bit number written in dotted decimal form. It provides us the networkaddress when we perform a Boolean AND of mask with the IP address. It alsodefine number of host bits in an address.

Class Size ofof networkaddress Part of

address,in bits

A 8B 16C 24

Size ofHostPart ofaddress,in bits24168

Default Maskfor EachClass ofNetwork

255.0.0.0255.255.0.0255.255.255.0

SUBNETTING

Basically it is a process of subdividing networks into smaller subnets.In case we have 2-3 small networks but we cant buy IP address for each andevery network. So here we use the basic concept of SUBNETTING i.e using onepublic IP address we will give them IP address and make them independentnetworks. For this we take some bits of host address and use them for networkaddress so we have different independent networks

Address Format when Subnetting Is Used (class A,B,C resp.):


8Network

24-xSubnet

xHost

16 16-x xNetwork Subnet Host

24 8-x xNetwork Subnet Host

And due to this mask changes to subnet mask and now the network address alsoincludes subnet address.

Example

If subnet mask is 255.255.240.0And an IP address for a computer is given as 142.16.52.4142.16.0.0 is network address0.0.48.0 is the subnet address0.0.4.4 is the host address of the computer

10001110.00010000.00110100.00000100 is ANDed with11111111.11111111.11110000.00000000and output is 10001110.00010000.00110000.00000000here first two octets represents Network address and third octet representssubnet address.It can be compared with a postal address as there is only one ZIP code (Networkaddress), different streets (Subnet address), and different house number (Hostaddress).

Some terminologiesNetworking models:

those are used with

Collision Domain- It is the group of PC’s in which collision will occurwhen two PC will transmit data simultaneously.

Broadcast Domain- It is the group of PC’s those will receive samebroadcast message.

CSMA/CD (Carrier Sense Multiple Access/ Collision Detection)- In thisprotocol when a PC wants to transmit any packet it sense the carrier i.e thepath ,if no other PC is using the carrier then only it sends. If two PCs startssending data simultaneously collision will occur. Both PCs will wait forsome random time and then initiate the same process.

MAC (Media Access Control) . The IEEE 802.3 (Ethernet) and 802.5(Token Ring) are the MAC sub layers of these two LAN data-link protocols.


Burned-in address: The 6-byte address assigned by the vendor makingthe card. It is usually burned in to a ROM or EEPROM on the LAN card andbegins with a 3-byte organizationally unique identifier (OUI) assigned bythe IEEE.

Locally administered address: Through configuration, an address that isused instead of the burned-in address.

Unicast address: Fancy term for a MAC that represents a single LANinterface.

PASSIVE COMPONENTS

Passive components are those devices which are used to provide connectivitybetween different networking devices.It includes

Cables Patch Panel Patch Cord I/O box Racks RJ-45 Connectors

CABLES

There are different Cabling options depending on the access method :

Twisted pairThe wires are twisted around each other to

minimize interference from other twisted pairs in the cable.

Twisted pair cables are available unshielded (UTP)

or shielded (STP). UTP is the most common type

and uses a RJ-45 Connector.

Typical lengths are up to 100m.

Twisted pair network uses a star topology.


CoaxialCoaxial cable uses BNC connectors.

The maximum cable lengths are around 500m.

Coaxial networks use a single bus topology

Fiber Optic

UTP and Co-axial cables are not capable for driving the data signals for longdistance i.e. UTP is capable of transmitting up to a distance 100 meters only Byusing the Fiber cables it is possible to send the data about 10 kilometers. Fiberoptic cable uses SC, ST, LC connectors (most common in use is SC connector)

In fiber cables the data is converted to light signals and the signal is made topropagate through the fiber cable. There are two types of Fibre optic cableavailable.

1. Single mode: In this mode typical length is up to 12km and data rate is1000Mbps. The core diameter is about 9.25 nm cable is known as 1000 base LXcable.

2. Multi mode: This mode is further categorised in two:

1) SX: Typical length is up to 500m and data rate is 1000Mbps.

2) FX: Typical length is up to 220m and data rate is 10000Mbps


PATCH CORD

RACKWe have to mount the patch panel somehow. The best way is to buy a rack.Basically, a rack is a pair of vertical rails with holes drilled in them so that we can

mount patch panels, hubs, and other network equipment. This made it easy toaccess the back of the patch panel and other networking components.

Cabling Guidelines

The RJ-45 ports on the switch support automatic MDI/MDI-X operation, so wecanuse standard straight-through twisted-pair cables to connect to any other networkdevice (PCs, servers, switches, routers, or hubs).We use only twisted-pair cables with RJ-45 connectors that conform to FCCstandards.

Connecting to PCs, Servers, Hubs and Switches

1. Attach one end of a twisted-pair cable segment to the device’s RJ-45connector.

Making Twisted-Pair Connections

2. The port where we are connecting the RJ-45 is a network card, attach theother end of the cable segment to a modular wall outlet that is connected


to the wiring closet . Otherwise, attach the other end to an available porton the switch.

Make sure each twisted pair cable does not exceed 100 meters (328 ft) in length.

Wiring Closet Connections

Today, the punch-down block is an integral part of many of the newer equipmentracks. It is actually part of the patch panel. Instructions for making connections inthe wiring closet with this type of equipment follow.

1. Attach one end of a patch cable to an available port on the switch, and theother end to the patch panel.

2. If not already in place, attach one end of a cable segment to the back ofthe patch panel where the punch-down block is located, and the other endto a modular wall outlet.

3. Label the cables to simplify future troubleshooting.


NETWORKING DEVICES

Networking devices do various kind of jobs like transferring the data to signals,providing connectivity to different network devices, transferring the data in form ofpackets or frames form one device to other. These are the central connectionsfor all the network equipments and handles a data type known as frame orpacket. Actually frames/ packet contain data and the destination address ofwhere it is going. When a frame is received, it is amplified and then transmittedon to port of destination PC. But different networking components do this job in

diff form at diff layers.

NETWORK INTERFACE CARDA Network Interface Card (NIC) is a circuit board that plugs into both clients andservers and controls the exchange of data between them (A specific software―driver‖ must be installed depending on the make of the NIC. A physicaltransmission medium, such as twisted pair or coaxial cable interconnects allnetwork interface cards to network hubs or switches. Ethernet and Token Ringare common network interface cards. Today’s cards supports 10baseT and

100baseT with automatic recognition.

HUBWhen the need for interconnecting more then 2 devices together then a deviceknown as hub comes to picture. Basically hub is a layer one device. i.e. itoperates on the physical layer of the OSI model. It is designed to dobroadcasting i.e when it gets any frame it broadcasts it to every port irrespectivethat whether it is destined for that port or not. Hub has no way of distinguishingwhich port a frame should be sent. Broadcasting results in lot of traffic on thenetwork which lead to poor network response. If two PC simultaneously transmitthere data packets and both are connected to a HUB, then collision will occur, sowe can say, it creates a single collision domain. On the other hand all PCsconnected to a hub will get a same message so a single broadcast domain willbe created.

A 100/1000 Mbps hub must share its bandwidth with each and every one of itsports. So when only one PC is broadcasting, it will have access to the maxavailable bandwidth. If, however, multiple PC’s are broadcasting, then thatbandwidth will need to be divided between all of these systems, which willdegrade the performance. They are usually Half-Duplex in nature.


SWITCH

Hubs are capable of joining more than two PC but having some demerits like iftwo PC would want to communicate at a time then there would be a collision andthe both PC would have to send the data once again. This shortcoming of Hub isovercame by Switches. Switches are intelligent devices which work on theLayer2 of the OSI model. Basically a switch keeps a record of MAC addresses ofall the devices connected to it. Using this information, it builds a MAC addresstable. So when a frame is received, it knows exactly which port to send it to,which increases the network response time.

Basic Working Principle of Switch.

1. At the time of initializing the switch the MAC address table is yet to be builtup. When a frame is send by some of the PC, it recognises the sourceMAC address and update the MAC address table.

2. If the destination is available in the MAC table then forward to thecorresponding PC.

3. If the destination MAC address is not present in the table then forwards inall the port available expect the incoming one. The designated PC willrespond for the data and it will send the acknowledge for the datareceived. This acknowledged data will be examined by the switch and theMAC address table would be up dated accordingly.

If two PC simultaneously transmit there data packets and both are connected toa SWITCH, then collision will not occur, so we can say, it creates a multiplecollision domain.

The switch supports broadcast. Hence we can call switches create singlebroadcast domain and multiple collision domains.

A 100/1000Mbps switch will allocate a full 100/1000 Mbps to each of its ports. Soregardless of the no of PC’s transmitting user will always have access to maxamt of bandwidth. They are usually Full-Duplex in nature.

Switches are of two types

1) Managed

2) Unmanaged

Managed switch supports SNMP (Simple Network Management Protocol)


Different switching Principles:-

1. Store-and-forward:- The switch fully receives all bits in the frame (store)before forwarding the frame (forward). This allows the switch to check the FCSbefore forwarding the frame. (FCS is in the Ethernet trailer.)

2. Cut-through:- The switch performs the address table lookup as soon as thedestination address field in the header is received. The first bits in the frame canbe sent out the outbound port before the final bits in the incoming frame arereceived. This does not allow the switch to discard frames that fail the FCScheck. (FCS is in the Ethernet trailer.)

3. Fragment Free:- This performs like cut-through switching, but the switch waitsfor 64 bytes to be received before forwarding the first bytes of the outgoingframe. According to Ethernet specifications, collisions should be detected duringthe first 64 bytes of the frame; frames in error because of a collision will not beforwarded. The FCS still cannot be checked.

Bridge is another device like switch which also operates basing on the MACaddress. But the Basic difference between the bridge and the switch is thatbridge works on software bases, but the switch works on hardware basic. TheSwitch works on ASICs ( Application Specific Integrated Circuits)

ROUTERSwitch and the Hub can only interconnect devices in a single LAN. Forinterconnecting two LAN or two or more different networks anther device knownas router is used. Its main job is to route ( sends ) packets to other networks andto do the routing ( establishing paths between networks ) it uses the IP address.A router is typically connected to at least two networks, commonly two LAN’s orWAN’s or a LAN and its ISP’s network. Routers are located at gateways, theplaces where two or more networks connect. Routers to determine the best pathfor forwarding the packet are using forwarding tables.

It is a layer 3 device i.e it operates at network layer of OSI model. The workingprinciple of the router is totally different from a switch. Router makes a tableknown as routing table, which contains all the IP address in the network, theinformation for IP address router obtains directly ( all configured IP address on it )or indirectly ( from neighbour routers ). When a packet is received it comparesthe destination IP address of the packet with the available IP addresses in itsRouting table. If the IP address is not available in the routing table then it simplydiscard the packet instead of flooding in all the ports like a switch.(DetailedInformation about router in chap )


Comparison between Hub, Bridge, Switch & Router

FeatureNumber ofbroadcastdomainsNumber ofcollisiondomainsForwards LANbroadcasts?

Hub Bridge Switch Router1 perrouterinterface1 perrouterinterface

No

Segment

1

1

11 perbridgeport

Yes

1

1 per switchport

YesYes; can beoptimized forlessforwarding

Forwards LANmulticastsOSI layer usedwhen makingforwardingdecision

InternalprocessingvariantsFrame/packetfragmentationallowed?Multipleconcurrentequal-cost pathsto samedestinationallowed?

N/A Yes No

N/A Layer 2

Store-and-forwardN/A

Layer 2Store-and-forward, cut-through,FragmentFree

Layer 3

Store-and-forward

N/A No No Yes

N/A No No Yes


LAN SOLUTION

CUSTOMER REQUIREMENT

There is a company, which has 2 offices. And the offices are 200 meters apart.The connectivity between these two offices is the main requirement to be fulfilled.In each office there are three different departments each department at differentfloor.

In building IstAt each floor there are 20 users and also at 3rd floor there are 2 Servers.

In building IIndAt floor 1st and 2nd there are 20 users each. And at 3rd floor there are 40 users.

The bandwidth requirement of each user is 100 Mbps while the bandwidthrequirement for the server is 1 Gbps.

All floors must be connected to a central switch to be placed at IInd floor in office2nd. And connectivity should be via optical fiber.

Everywhere there should be structured cabling.

Every switch should be provide with one GBIC slot for future connectivity ofserver.Every where smart and managed switch should be used.


SOLUTION

By looking at the requirement it is clear that we require a switch that has got 20ports and also 2 GBIC slots (one for optical fiber connectivity and one free slot isdemanded for future use).

Keeping this point into consideration we can use HCL 24 Port ManagedStackable Switch as this switch has got 24 ports and 2 GBIC slots and this switchis managed switch also.And with this 24 port switch we will use 24 port HCL made Patch PanelAnd for connectivity of patch panel with switch we require 3 ft Patch Cord. Asstructured cabling is must so we require UTP cable and I/O box and to connectPCs with I/O box we require 7ft Patch Cord.Here we will use Cat5e UTP cable because bandwidth requirement is 100 MbpsThis trend of connecting the users to the switch will be followed at each andevery floor but at floor 3rd of building IInd there are 40 user so here instead of 1switch we require 2 switches.

At 3rd floor of building 1st 2 servers are also present whose bandwidthrequirement is 1Gbps. So now we have two options either to connect with UTPcable or Fiber optic cable. But here we will use fiber optic as we are alreadyusing it so thee is no need to waste money on UTP Cat 6 Cable. So here we willsimply use the fiber optic patch cord to connect the server to switch.

Now only one thing is left i.e. connection of switches to a central switch placed at2nd floor of IInd building.As the connection requirement is via optical fiber so we at central location werequire a switch having all its ports as GBIC slots and no of ports should not bemore than 8 as there are only 7 24 port switches in use (one optical cable linefrom each switch)

Now here as the distance between the two offices is only 200 meters so here wewill use multimode optical fiber and that too FX type and as the cable is to be laidin open so outdoor armored cable will be use.


ROUTER

ROUTER INTERNAL COMPONENTS

Like a computer, a router has a CPU that varies in performance and capabilitiesdepending upon router platform. It has typically 4 types of memory in it.:

ROM- It is used to store the router’s bootstrap startup program, operating systemsoftware, and power-on diagnostic tests programs. We can also upgrade ourROM

FLASH MEMORY- It holds operating systems image(s). Flash memory iserasable, reprogrammable ROM. Our IOS software is present in this memory andwe can upgrade it also. Flash content is retained even when we switch off orrestart the router.

RAM- It is used to store operational information such as routing tables, router’srunning configuration file. RAM also provides caching and packet bufferingcapabilities. Its content is lost when we switch off or restart the router. When weconfigure the router at that time actually we are writing in RAM.

NVRAM- It is used to store the router’s startup configuration file. It does not losedata when power is switched off. So the contents of startup configuration files aremaintained even when we switch off or restart the router.

ROUTER’S NETWORK INTERFACES

Ethernet or Token Ring interface are configured to allow connection to a LAN.

Synchronous serial interfaces are configured to allow connections to WANs.

ISDN BRI interfaces are configured to allow connection to an ISDN WAN.

All cisco routers have a console port that provides an EIA/TIA-232asynchronous serial connection. Console port can be connected to computersserial connection to gain terminal access to router.


Most routers also have an auxiliary port that is very similar to console port but,is typically used for modem connection for remote router management.

CONFIGURING THE ROUTER

There are three methods for configuring the router:

1) Through console port:- The console port is used for configuring a routerlocally with the help of a PC or a Laptop. The console port of the router isconnected to the serial i.e COM port of the router. The detailedconfiguration is given in the section.

2) Through the AUX port:- The aux ( auxiliary ) port is accessed from amodem located faraway from a router through the PSTN ( Public SwitchedTelephone Network ) and the configuration is done.

3) Through Telnet:- Line vty ( virtual terminal ) 0 to 4 are used for theconfiguring the router by telnet.

Configuring Router through Console port

We use HyperTerminal Program to open a console session and log into therouter locally. This console connection allows to connect to and to communicate


with router without having to connect to the network to which it belongs. Now, thePC becomes the console that allows to enter commands and communicatedirectly with the router. To set up a console session, we use the workstation’sWindows HyperTerminal (terminal emulation) program. Now first of all weconfigure the COM port settings, then log into the router to interact with the IOScommand line interface (CLI). These are the com port settings:

96008N1On/off

After pressing enter or OK to accept these settings, we came across a blankwindow. This is a session window.

The Following steps are adopted to access a router through the console port witha Windows based PC.

Access Hyper terminal:- Start Menu Programs Accessories Communication Hyperterminal

Connect to the device of the PC


COM 1 Setting

Hyper terminal Screen


After connecting the router that will boot and after booting the followingprocedures will be adopted.Router> enable

Now automatically prompt asking for password will appear on the screen like this:

Password:Now write password over here. This is done to secure access to router. After this

Router#will appear on the screen this shows that we are in privileged mode and now wetry to enter in configuration mode.

Router# configure terminalThis is done to enter configuration mode.Now starts the configuration of routerNow we will assign IP address to each and very interface connected to router.Subnet mask should be given with a proper care. Following steps are to befollowed:

For configuring ethernet interface:

Router# config terminalRouter (config)# interface ethernet 0


Engineering

Ccna report