Showing posts with label Networking. Show all posts
Showing posts with label Networking. Show all posts

Wednesday, 18 December 2013

Concept of Internetworking

  Internetworkin involves connecting tow or more distinct nodes or computer networks segments together to form an internetwork (often shortened to Internet} using internetworking devices, such as bridges, switches, router and gateways which operate at the various levels of the OSI Reference Model to connect them together to allow free flow of packets back and both between them . The network can further be divided into various brances or categories, namely LAN, MAN or WAN depending upon specific context of use.


Local Area Network: The network whose coverage falls within the range of 10 m to 1km, that is form small room to the campus of offices is called as Local Area Network.

Metropolitan Area Network : The network whose coverage falls within the range of 1 km, that is, within the vicinity of the city limits is called as Metropolitan Area Network.

Wide Area Network: The network whose coverage falls within the range of 10 km to 1000 km, that is,  spanning from one city to another city or may be to another county altogether is called as Wide Area Network.
Today, the Internet is largely and loosely based on the OSI Reference Model that provides us the seven layers as decribed below. gives the comparative schedule used, address supported and lenth of the address.

Tuesday, 17 December 2013

The Network Layer Design Issues

 The network layer is one pf the most signification layers of the entire OSI Reference Model. The network layer is a layer at which the IP address works. If The communication is between two or more than system across different networks, then only we require the help of the IP address to transfer the data packet from one node to require the help of the IP address to transfer the data packet from one node to another, otherwise the hardware address supported by the data link layer is good enough for the transmission of the data packets between tow of more machines within the same network.
Some concepts that were kept in mind while designing the network layer are as follows :

1. The services should be independent of the subnet (a subset of the larger network} K also technology.

2. The transport layer should be shielded from the number, type and topology of the subnets present.

3. The network address made a available to the transport layer should use a uniform numbering plan across the different types of network starting from LAN to MAN to WAN.
The network layer of the ISO -OSI Reference Model supports both the connection oriented data streaming which is achieved through TCP and connectionless data streaming which is achieved through
UDP (Unreliable or User Datagram Protocol). The connection that is talked of in the above protocol should possess the following properties:

1. The source machine should first establish the connection to the destination machine. Each and every connection is identified and assigned a unique number which is released after all the data has been transferred from the source to the destination.

2. Mode of communication is kept full duplex have efforts are made so that packets are transmitted in doth the direction.
3. Both the source and the destination machine have the full right and authority that decide upon the various parameters, such as quality, cost duration, effort, of the devices that have to be used to provide the services.

Article -By Amit


Tuesday, 10 December 2013

WHAT IS A NETWORK TOPOLOGIES

 A network is any collection of independent computers that communicate with one over a shared network medium.  There may be or more `computer . When computer are joined in a network, you can share files and devices, such as printers or CD-ROM drives. Different at multiple locations can also be accomplished using phone service and other modes of communication services.Now there is access to more service the form of e-mail, Internet and sharing of databases etc. Because of these benefits an others, computer networking is becoming increasingly  important.
In order to establish network of computer, we require at least two computer, Networking Interface came (NIC), and transmission medium. The transmission medium may be a wire are cable although wireless communication between networked computer and peripherals is also possible.
We also require network operating system software, such as Microsoft Windows NT or 2000, Novell  NetWare, Unix and Linux

Friday, 22 November 2013

TYPE OF NETWORK

Network can be characterized using one or more technical or operational attributes.
Example., (Type of technology or number of connected users and devices)
One common attribute  used to categorize networks is geographic area or span. where a network  is labeled on the basis of the physical area it covers.
The five most common type of networks in terms of geographic area from the smallest to the largest are:

  • Personal area networks (PANs).
  • Local area networks (LANs).
  • Campus area networks (CAMs).
  • Metropolitan area networks (MANs).
  • Wide area networks (WANs).

Personal Area Networks (PANs)

PANs cover areas generally associated with individual workspaces (e.g., a home office or an office cubicle). Within these spaces, individual networks connecting two or more devices may be enabled using wireless technologies.

Local Area Networks (LANs)

LANs cover areas generally associated with some or all of the space within a building. In most cases, multiple workspace devices are connected to shared devices (e.g., switches, servers) to form a LAN.
One LAN can serve a single department, multiple groups, or all users within a building. Cabling, wireless, or a combination of both can be used to link LAN devices, 

Campus Area Networks (CANs)

CANs are created by linking the LANs located in two or more buildings that are in close proximity to each other, as Connections between the buildings can be made using cabling or wireless technologies.
NOTE: The term campus LAN is also used to describe a CAN.

Metropolitan Area Networks (MANs)

MANs are created by linking the networks located at two or more sites within a city. Connections can be made using cabling or wireless technologies, with optical fiber cabling often used to link a customer’s buildings to a facility operated by a telecommunications provider, 

Wide Area Networks (WANs)

WANs are created by linking the networks located at two or more sites over geographic distances that extend beyond the span of a single metropolitan area. These include links between cities, countries, and in the case of global WANs, continents. Telecommunications circuits link each building to facilities operated by a telecommunications provider (same as MANs), 

Saturday, 16 November 2013

INTERNET ROUTING PROTOCOLS

     There are various networks and computer system on the Internet. In order send data to a particular system, the address of that system in the network has to be specified and using this address the data reaches its destination. In the addressing scheme IP addresses are used to route data ti its destination. In packet switching, the data is divided into small  equal- sized packets and these packets are re-assembled into original data. The path that data follows to reach its destination is called 'routers'. When a computer sends data packets to another computer on the network, all the packets are given the IP address of another computer and then these packets are sent to the nearest router on the network. The router then sends the packets to the destination computer through the Internet.
In the Internet, routers are organised in the form of  a tree structure. Routers that are used to transmit information within independent computer system are called interior routers. which use Interior Gateway Protocols for routing data. Routers that transmit information between independent computer system are called exterior routers, which use Exterior Gateway Protocols (EGP) for routing data.

Interior Gateway Protocol (IGP)
IGP are used to route data in a Local Area Network such as a network in an office building. Following are the two type of IGP:

  • Routing Information Protocol (RIP)
  • Open Shortest Path First(OSPF)
Routing Information Protocol 
A routing database is maintained by RIP for storing information about the fastest route from one computer to another. An update process can be used by each router to inform other routers about the fastest route from its view point. Each router uses an update algorithm to update its routing database as per the fastest routes told by the eighbouring routers.
Open Shortest Path First
OPE maintains a database containing information about all the connection in the Local Area Network. The following terms describe the operating  of OSPE algorithm:
Startup : On turning on a router, Hello packets are sent by it to all the neighbouring routers. In return, it also receives their Hello packets and creates that are agreeable to synchronisation. Hello packets are these that are used to tell neighbouring routers that the sending router is now online.
Shortest Path Tree: Each router calculates a mathematical data structure, referred to as the 'shortest path tree' describing the shortest path to reach each of the destination addresses. For each communication, this address  tells you which is the the closest router to which the data packets should be sent, that is, open shortest path frist.