In many networks, the basic unit of information exchanged between two in ronaldweinland.info In working, the computer network will more likely be successful in the company. Lauren has decided to review basic network concepts with her coworkers as. This book is meant as a serious and more-or-less thorough text for an introductory college or graduate course in computer networks, carefully.
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An Introduction to Computer Networks 1 An Overview of Networks. 13 of selected important network applications, or the basics of network. This tutorial is prepared for the beginners to help them understand Data. Communication and Computer Networks. Prerequisites. Before proceeding with this. Computer Networking: Principles, Protocols, and Practice was written by Dr. Olivier Bonaventure of the. Université to this basic service have been proposed.
Computer networks consist of many different components, technologies and protocols working together. Most modern networks use wireless wi-Fi as the main connection media and networks tend to be a mixture of wired and wireless. The diagram below shows a wired Ethernet network. To work each device must be connected to a Ethernet hub or switch. For a Wireless network the devices must connect to a wire access point as shown in the diagram below.
It is physically similar to phone cables, but can transport much more data. But cables and computers alone do not make a good network, so one early solution was to use a network hub. The Ethernet cables from the computer connect to the device similar to the hub of a bike wheel—where all of the spokes come together in the center. An example of how a hub works is shown below.
Computer A wants to send a message to computer B. It sends the message through the Ethernet cable to the hub, then the hub repeats the message to all of the connected computers. A network using a hub can slow down if many computers are sending messages, since they may try and send messages at the same time and confuse the hub.
To help with this problem, networks began to use another device called a switch. Instead of repeating all messages that come in, a switch only sends the message to the intended destination. This eliminates the unnecessary repetition of the hub.
Using a switch, computer A sends a message to computer B—the other computers do not see the message. Those computers can send other messages at the same time without interfering.
Switches do have a limitation though—they only know about the addresses of equipment that is plugged directly into them. So, you can only send messages to a small number of devices—however many ports the switch has! If you need to send a message to a computer on another network, it will need to be sent through a router, which we discuss next.
Routers and Firewalls Routers do the majority of the hard work on a network - they make the decisions about all the messages that travel on the network, and whether to pass messages to and from outside networks. There are three main functions: Separate and Bridge Routers separate networks into sections, or bridge different networks together, as we see in the example above—the private network of In the example of Firewall and Protect They can filter messages or keep users out of private networks.
Most routers have a Firewall built in. This is a software function that keeps unwanted messages from reaching the computers on the inside, or private part, of the network. Let us take another look at As it turns out, that postal service building is acting as a Router. In this case, the postal service building is routing messages between the rest of the Internet using its public address and the street with private addresses.
Ethernet A type of networking protocol—it defines the types of cables and connections that are used to wire computers, switches, and routers together. If it begins with , then it's a Class C network. OSPF, or Open Shortest Path First, is a link-state routing protocol that uses routing tables to determine the best possible path for data exchange. Firewalls serve to protect an internal network from external attacks.
These external threats can be hackers who want to steal data or computer viruses that can wipe out data in an instant. It also prevents other users from external networks from gaining access to the private network. This is one of the easiest to setup and maintain.
Gateways provide connectivity between two or more network segments. It is usually a computer that runs the gateway software and provides translation services.
This translation is a key in allowing different systems to communicate on the network. One major disadvantage of star topology is that once the central hub or switch get damaged, the entire network becomes unusable.
This is one of the protocols that are used for remote access.
Tracert is a Windows utility program that can used to trace the route taken by data from the router to the destination network. It also shows the number of hops taken during the entire transmission route. When you are accessing the resources that are shared by one of the workstations on the network, that workstation takes a performance hit.
A hybrid network is a network setup that makes use of both client-server and peer-to-peer architecture. Its main task is to automatically assign an IP address to devices across the network. It first checks for the next available address not yet taken by any device, then assigns this to a network device.
This is a set of protocol layers that is designed to make data exchange possible on different types of computer networks, also known as heterogeneous network.
Routers have built in console that lets you configure different settings, like security and data logging. You can assign restrictions to computers, such as what resources it is allowed access, or what particular time of the day they can browse the internet. You can even put restrictions on what websites are not viewable across the entire network.
This is possible because FTP is platform independent. Default gateways provide means for the local networks to connect to the external network. The default gateway for connecting to the external network is usually the address of the external router port.
What can be considered as good passwords? Good passwords are made up of not just letters, but by combining letters and numbers.
A password that combines uppercase and lowercase letters is favorable than one that uses all upper case or all lower case letters. Passwords must be not words that can easily be guessed by hackers, such as dates, names, favorites, etc.
Longer passwords are also better than short ones. The proper termination for unshielded twisted pair network cable is ohms. Netstat is a command line utility program. The number of possible network IDs is 2 raised to 21 or 2,, The number of host IDs per network ID is 2 raised to 8 minus 2, or Cables that are too long would result in signal loss. This means that data transmission and reception would be affected, because the signal degrades over length.
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