Different Modes Of Router

Modes Of Router:-

Setup Mode:- (Create the initial configuration.)
Basic Mode:- It gives Enough Configuration.
Extended Mode:- It give the configuration of some global parameters as well as interface.

To Enter Setup Mode just type Yes or y in configuration dialog.

User EXEC Mode:-
In this mode you only get some basic monitoring command of router.
Change terminal setting, limited show command, ping, trace, telnet etc.
you can get a list of available commands by just entering a question mark (?) in any command mode.
 Type "?"

Privileged EXEC Mode:-
In this mode you Monitoring as well as some troubleshooting command of router.
All Show commands, copy, delete, debug etc.

Global Configuration Mode:-
In this mode You Configure router according to requirement like host name, routing configuration etc.
You can modify as well as delete the configuration which affect the router globally.

Line Configuration:-

In this mode you set password to console, auxiliary ports and virtual terminal (VTY) for securing your router from other person (hacker).

 

Interface Configuration:-

In this mode you Configure router interface means you set IP address to ports either it is fastethernet, serial etc. 

Sub-interface Configuration:-

In this mode you create a virtual interface by dividing one physical interface into multiple logical interfaces.

Rommon Mode:-

When you did not remember your router password or any Boot failure with router at that time you use this mode.

Router Modes

Command Mode	Access Method	Prompt	Exit Mode
User EXEC Mode	Start session (By Default)	Router>	Type logout or exit command
Privilege EXEC Mode	Use enable command	Router#	Type disable command
Global Configuration Mode	Use configure or configure terminal	Router(config)#	Type exit command or press "ctrl+z"
Interface Configuration	Interface command	Router(config-if)#	Type exit, end command or press "ctrl+z"
Sub-interface Configuration	Sub-interface with interface command	Router(config-subif)#	Type exit command
Rommon Mode	Use reload command (press ctrl+pause break or ctrl+c at the time of booting process)	rommon 1>	Some router support reset, reboot and reload command for exit from rommon mode.
Line Configuration	Use line command	Router(config-line)#	Type exit command

Cisco Router

Router

⦁ A router is a networking device which makes communication possible between two or more different network present in same or different geographical locations.

⦁ It works on layer 3 of the OSI model so it is known as L3 device.
⦁ It also selects the best path at minimum cost from the routing table and    forward the packet which is the best one for communication.

Vendors of Router:-

⦁ Cisco
⦁ Juniper
⦁ Nortel
⦁ Multicom
⦁ D-Link
⦁ Linksys
⦁ 3com

Cisco Three-Layered Hierarchical Model:-

A. Access Layer :- Router which is used by the small organization and are also known as the Desktop or Company layer routers. Router series: 800,1000,1600,1700,2500 etc.

B. Distribution Layer:- Router which is used by the ISPs and are also known as an ISP layer Router. Router series: 2600,3200,3600 etc.

C. Core layer:- Router which is used by the Global ISPs and are also known as Backbone Router. Router Series: 6400,7200,7400,10000 etc.

Classification of Router:-

Fixed Router:-
It’s also known as Non-Upgradeable Router Because in this router we can’t add or remove the Ethernet or serial interface according to own requirement.
It does not have any slot for adding or removing the interface.

Modular Router:-
It’s also known as Upgradeable Router Because in this router we can add or remove the Ethernet or serial interface according as per the requirement.
It has number of slot for adding or removing the interface.

Bringing up a Router:-

⦁ First switch-on and it goes for Power-on self Test (POST).
⦁ It load Cisco IOS from flash memory if it present on it.
⦁ The IOS then proceeds to load and looks for a valid configuration which is stored by default in non-volatile RAM, or NVRAM.
⦁ IOS is decompressed into RAM
⦁ After IOS is decompressed into RAM, the IOS then loaded and start running the router.

Fig: Bringing Up a Router

Following Message Appear when we first boot or reload a router:

Fig: Cisco Router IOS

Subnetting

Note:

Step 1: 1st we represent the / value in binary notation. calculate the CIDR value for New Subnet Mask (N.S.M).

Step 2: 1st we check how many on-bit in your IP-Address for example 195.168.10.1 this IP belongs to Class C and there is total 3-network and one host (N=24 bits, H=8 bits). 1st we check how many on-bit in your Host part not in network part. if there is any on-bits in your Host part then you put in formula
i.e. (2^on-bits)

Step 3: In this step we check how many off-bits in your IP address. for example: Total 8 off-bits & put these number of bits in formula
i.e. (2^off-bits-2)

Step 4: In Block Size we directly subtract your N.S.M with 256.
i.e. (256 - N.S.M)

Step 5: Range always start from 0. i.e. (0-255)

How to calculate Subnetting?

Q.1 Subnet the IP Address 195.168.10.0/24?a) How many subnet?b) How many host per subnet?c) What is block size?d) What is the range?e) What is the broadcast address?

Solution:

IP Address     =    195.168.10.0/24
Subnet mask  =    255.255.255.0 (class c)

In binary notation
11111111.11111111.11111111.00000000
New Subnet Mask  = 255.255.255.0

Number of Subnet = (2^on-bits)
                               = 20
                               = 1

Number of host/subnet = (2^off-bits-2)
                       = 28
                       = 256

Block Size = (256 – New Subnet Mask)
          = 256 – 0
          = 256

Range        = (0-255)

1st Subnet:
IP Address          = 195.168.10.0
1st Valid Host     = 195.168.10.1
2nd Valid Host    = 195.168.10.2
                                                   -
                                                   -
                                                   -
Last Valid Host   = 195.168.10.254
Broadcast      = 195.168.10.255


a) Number of Subnet = 1
b) Host/subnet           = 256
c) Block Size             = 256
d) Range                    = (0-255)
e) Broadcast address = 195.168.10.255

Default Routing

Default Route is also known as gateway of last resort which is a special type of static route. Static route allows traffic to be forwarded even without a specific route to a particular network.In default route all network and subnet mask is identified by all zeros (0.0.0.0 0.0.0.0).

• It is used when the destination is unknown, for example internet.
• It can also be used at the end location where there is only one exit path for any destination.
• Default routes help in reducing the size of your routing table.
• If the routers do not find an entry for the destination network in a routing table the router will forward the packet to its default route.
• It’s also known as default gateway.

Router 0:
Router>enable
Router#configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)#interface FastEthernet0/1
Router(config-if)#ip address 192.168.10.1 255.255.255.0
Router(config-if)#no shutdown
%LINK-5-CHANGED: Interface FastEthernet0/1, changed state to up
%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to up
Router(config-if)#exit
Router(config)#interface Serial 0/1/0
Router(config-if)#ip address 192.168.30.1 255.255.255.0
Router(config-if)#clock rate 64000
Router(config-if)#no shutdown
%LINK-5-CHANGED: Interface Serial0/1/0, changed state to up
%LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/1/0, changed state to up
Router(config-if)#exit
Router(config)#do write
Building configuration...
[OK]

• Configure a Default Routing Protocol:
Router(config)#ip route [destination network] [subnet mask] [next hop/exit interface]
Router(config)#ip route 0.0.0.00.0.0.0 192.168.30.2

Router 1:
Router>enable
Router#configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)#interface FastEthernet0/0
Router(config-if)#ip address 192.168.20.1 255.255.255.0
Router(config-if)#no shutdown
%LINK-5-CHANGED: Interface FastEthernet0/0, changed state to up
%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to up
Router(config-if)#exit
Router(config)#interface Serial 0/1/0
Router(config-if)#ip address 192.168.30.2 255.255.255.0
Router(config-if)#no clock rate
This command applies only to DCE interfaces
Router(config-if)#no shutdown
%LINK-5-CHANGED: Interface Serial0/1/0, changed state to up
%LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/1/0, changed state to up
Router(config-if)#exit
Router(config)#do write
Building configuration...
[OK]

• Configure a Default Routing Protocol:
Router(config)#ip route [destination network] [subnet mask] [next hop/exit interface]
Router(config)#ip route 0.0.0.0 0.0.0.0 192.168.30.1

Static Routing Protocol

• Static routing is not really a type of routing protocol, but it is a network routing technique because it usually managed by the network administrator for configuration as well as a selection of a network route. 
• Static routing can be used if there is the smallest network for route configuration and there is no need to exchange any change in route in the future.
• It is easy to configure, but it is done manually.
• It used for small organizations because the administrator needs to learn all the routes.
• It doesn’t handle failures outside the networks well because it reconfigured or any update done manually to fix the network problem.
• In static routing administrator constructs the routing table for every router by inserting all the entries of network (destination).
• Static routes have an Administrative Distance (AD) of 1.
• It is very secure because it can’t send any advertisement, like other routing protocols.
• In static routing protocol there is no routing algorithm or update mechanism are required (no need extra CPU and memory).
• If there is any link fails, then static route can’t reroute traffic automatically. It needs to reroute traffic manually.

Static Routing

 Configuration  a static routing:

Router 1:
Router>enable
Router#configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)#interface FastEthernet0/0
Router(config-if)#ip address 192.165.10.1 255.255.255.0
Router(config-if)#no shutdown
Router(config-if)#exit
Router(config)#interface Serial0/1/0
Router(config-if)#ip address 20.1.1.1 255.0.0.0
Router(config-if)#clock rate 64000
Router(config-if)#no shutdown
Router(config-if)#exit

 Configure a static route:
Router(config)# ip route [destination network] [subnet mask] [next hope IP]
Router(config)#ip route 172.16.0.0 255.255.0.0 20.1.1.2

Router 2:
Router>enable
Router#configure terminal
Router(config)#interface FastEthernet0/0
Router(config-if)#ip address 172.16.1.1 255.255.0.0
Router(config-if)#no shutdown
Router(config-if)#exit
Router(config)#interface Serial0/1/0
Router(config-if)#ip address 20.1.1.2 255.0.0.0
Router(config-if)#no shutdown
Router(config-if)#exit

 Configure a static route:
Router(config)# ip route [destination network] [subnet mask] [next hope IP / exitinterface ]
Router(config)#ip route 192.165.10.0 255.255.255.0 20.1.1.1

NOTE :
• Next hope IP is the IP address of the directly connected router which the packet will
be send, after it leaves the Router1.
• Exit interface is the interface of Router1 which the packet leaving

OSPF Routing Protocols

• OSPF is an open standard routing protocol, it means it is implemented for large scale that are not used by other routing protocols either it is a distance vector(RIP) or hybrid protocol (EIGRP), and it works on a variety of network vendor including Cisco. It uses Dijkstra algorithm, i.e. best for implementing in a hierarchical design. 

• OSPF introduce the concept of areas for managing and controlling the network traffic. It creates a neighbor relationship with adjacent routers in the same area.

• OSPF provides hierarchical network design with multiple different areas and all other areas must be connected to the area 0. 

• OSPF uses a multicast address (224.0.0.5) for routing updates (all OSPF routers), but all designated routers use the different multicast address (224.0.0.6) for routing updates.

• OSPF is a link-state routing protocol which is also known as “shortest path first” protocol.

• It creates three separate tables for understanding the inter-network.

• First table gets all the information about directly connected neighbor. 

• Second table determines the topology of the entire inter-network. 

• Third tables used as routing table.

• OSPF consists of the areas and autonomous systems. 

• It have unlimited hop count.

• On OSPF routing overhead is decreased and convergence is faster. 

• It sends the packets after every 5 seconds. 

• It also supports authentication. 

• It only supports equal cost load balancing. Metric is cost (cost= 10^8/b.w).

IP ADDRESS

IP stands for Internet protocol. An IP address is a unique 32-bits logically assigned binary number of four octets (8-bits), which is represented in decimal notation, designed for a particular device. Hosts and routers used in the TCP/IP protocol suite are identified by the IP addresses. The IP address is also divided into classes and each class has its specific range

Continue reading

Wireless

Wireless

The institute of electrical and electric appliances (IEEE) on the organization that defines industry wide standards in the fields of electrics and computing has set guidelines or standards for wireless networking commonly called the wireless fidelity (WI-FI) standard.

Basic of wireless Networking:

For the distribution of data, the wireless network standard uses cellular radio signals or links to provides network connectivity to PCs and laptop through a transmitter/receiver unit (transceiver), generally known as an access point or wireless access point (WAP). WAP transmit and receiver signals to and from wireless network adapters.

Following are vital factors of it:

 1) Weather condition between satellite and PC may reduce the power of the signal in a network because of the interface caused by induced electromagnetic waves due to cloud collision. This distorts the signals, which in turn affects the transmission of the signal over a network.

 2) Security

 3) Speed

• Hardware Requirement of a wireless Network:

Wirelesses networking capability of one form or another are built into many modern computing devices. Infrared transceiver ports have been made standardized computers, wireless Ethernet and Bluetooth capabilities are increasingly becoming popular as integrated components, or can easily be added by using peripheral component interconnect (PCI) or personal computer memory card International Association (PCMCIA) add-on cards.

• Wireless Access Point (WAP):

WAP is a device that sends and receives data signals that are used to establish a connection between two devices in a network. WAP is also referred to as a transceiver because it is used to transmit and receive data signals. A transceiver enables a user to connect two or more wireless devices and communicate with other users. WAP also acts as the point interconnection between WLAN.

    WAP can be divided into two types, hardware access point and software access point. Hardware access point is to define as a physical device used to establish a connection between two devices and software access point is defined as computers that include a wireless network interface card.

Hardware and Software

Monitor

• Cathode Ray Tube Monitor:

It is invented by Karl Ferdinand Braun. A beam of electrons strikes towards the CRT, and the collision of electrons with phosphorus produce light.(more about this topic and LED also).

• Liquid Crystal Display Monitor (LCD):

It uses thin film transistor technology to display. The TFT is a part of the LCD. The main difference between LCD and TFT monitor is that the TFT monitor uses a tiny transistor for each pixel on the display. This allows the electrical current that illuminates the display to be turned on and off at a faster rate. Which makes the display brighter and shows motion smoother. These transistors are used in high-quality flat panel LCDs. The LCD monitor’s do not use this technology due to this LCD display could not keep up with fast moving images.

Characteristics of a Monitor:

Dot pitch is also called pixel pitch. It is the measurement that represents the diagonal distance between colored phosphorous dots on the display screen. The dot pitch for monitor in personal computer ranges from 0.15mm - 0.30mm. Refresh rate represents the number of times the image is displayed per second. The number is measured in Hz. Higher refresh rate less image flicker on the screen refresh rate less than the 60Hz produces an image flickering, meaning the image appears again and again.

Monitor Cable Technology:

1. Video Graphics Array (VGA):
VGA card represents the computer display standard introduced with the IBM in 1987. It is a video adapter, which is used for transferring the video signals in the monitor. A generic VGA has 15 pins and each pin (except of 3 spare pins) is defined for transferring a particular color signal. The display information is sent to the monitor in the analog form through a VGA. Nowadays VGA adapters not fully support the use of digital monitors, a new standard cable DVI has been designed.

2. Digital Video Interface (DVI):
DVI technology is based on transition minimized differential signaling (TMDS), which introduces a transmission method for sending digital information to a PC. It is developed by silicon image, which produces a high-speed digital-interface. TMDS receives signal from the resolution and refresh rate that the monitor uses, and spreads the signals out over the bandwidth to optimize the data transfer from the system (CPU) to monitor.

BIOS:

The BIOS Setup utility is installed with a set of default value designed that ensures that the system operates efficiently. The Bios setup utility stores information about the motherboard components and the configuration of other devices that are connected to it and use this information to test and initialize the components when it is started.

In case you want to add new components to your system such as the disk drive, then you will have to make changes to the BIOS setup utility. In certain circumstances, the system may generate an error message, which make changes to the BIOS setup utility. This happens when the system finds an error during the power on self-test that it carries out at startup. 

POST:

The POST stands for Power on Self-Test. POST is a diagnostic testing sequence that runs a computer's basic input/output system to determine if the keyboard, mouse, RAM, disk drive and other hardware components are working correctly then the computer begins to boot. However, if the hardware components are not detected or it is not working properly, the BIOS generates an error message. It acts as an interface between the operating system and hardware when booting.

Setup:
The setup function is a menu-drive program. It helps you configure the motherboard and the chipset settings.

Bootstrap Loader:

It is a program which resides in the ROM of the computer and is automatically executed by the processor when the computer is turned on. It is the responsibility of the bootstrap loader to load the operating system from the floppy or hard disk drives to load the operating system towards the normal functioning of the computer.

Manufacturers of BIOS:

i) American Megatrends Inc. (AMI): AMI was the 1st manufacturer to build motherboards based on Intel's 386 and 486 processor platform. It was founded in 1984.

ii) Award: It is a leading manufacturer of BIOS, and Now merged with Phoenix Technologies.

iii) MR BIOS: It was manufactured by Microid Research Inc. which was founded in 1989.

iv) Phoenix Technologies: It was founded in 1979 and developed its 1st commercial BIOS in 1983.