The Difference Between Hubs, Switches and Routers

Some technicians have a tendency to use the terms routers, hubs and switches interchangeably. One minute they're talking about a switch. Two minutes later they're discussing router settings. Throughout all of this, though, they're still looking at only the one box.  Ever wonder what the difference is among these boxes?  The functions of the three devices are all quite different from one another, even if at times they are all integrated into a single device. Which one do you use when? Let's take a look...

Hub, Switch, and Router Defined

Hub 

A common connection point for devices in a network. Hubs are commonly used to connect segments of a LAN. A hub contains multiple ports. When a packet arrives at one port, it is copied to the other ports so that all segments of the LAN can see all packets.

Switch 

In networks, a device that filters and forwards packets between LAN segments. Switches operate at the data link layer (layer 2) and sometimes the network layer (layer 3) of the OSI Reference Model and therefore support any packet protocol. LANs that use switches to join segments are called switched LANs or, in the case of Ethernet networks, switched Ethernet LANs.

Router 

A device that forwards data packets along networks. A router is connected to at least two networks, commonly two LANs or WANs or a LAN and its ISP.s network. Routers are located at gateways, the places where two or more networks connect. Routers use headers and forwarding tables to determine the best path for forwarding the packets, and they use protocols such as ICMP to communicate with each other and configure the best route between any two hosts. 

The Differences Between Hubs, Switches, and Routers on the Network

Today most routers have become something of a Swiss Army knife, combining the features and functionality of a router and switch/hub into a single unit. So conversations regarding these devices can be a bit misleading — especially to someone new to computer networking.

The functions of a router, hub and a switch are all quite different from one another, even if at times they are all integrated into a single device. Let's start with the hub and the switch since these two devices have similar roles on the network. Each serves as a central connection for all of your network equipment and handles a data type known as frames. Frames carry your data. When a frame is received, it is amplified and then transmitted on to the port of the destination PC. The big difference between these two devices is in the method in which frames are being delivered.

In a hub, a frame is passed along or "broadcast" to every one of its ports. It doesn't matter that the frame is only destined for one port. The hub has no way of distinguishing which port a frame should be sent to. Passing it along to every port ensures that it will reach its intended destination. This places a lot of traffic on the network and can lead to poor network response times.

Additionally, a 10/100Mbps hub must share its bandwidth with each and every one of its ports. So when only one PC is broadcasting, it will have access to the maximum available bandwidth. If, however, multiple PCs are broadcasting, then that bandwidth will need to be divided among all of those systems, which will degrade performance.

A switch, however, keeps a record of the MAC addresses of all the devices connected to it. With this information, a switch can identify which system is sitting on which port. So when a frame is received, it knows exactly which port to send it to, without significantly increasing network response times. And, unlike a hub, a 10/100Mbps switch will allocate a full 10/100Mbps to each of its ports. So regardless of the number of PCs transmitting, users will always have access to the maximum amount of bandwidth. It's for these reasons why a switch is considered to be a much better choice then a hub.

Routers are completely different devices. Where a hub or switch is concerned with transmitting frames, a router's job, as its name implies, is to route packets to other networks until that packet ultimately reaches its destination. One of the key features of a packet is that it not only contains data, but the destination address of where it's going.

So, in short, a hub glues together an Ethernet network segment, a switch can connect multiple Ethernet segments more efficiently and a router can do those functions plus route TCP/IP packets between multiple LANs and/or WANs; and much more of course. 

How to Convert PPS to PPT

Files with .pps and .ppt extensions are both created with Microsoft PowerPoint software. A .pps file opens directly as a PowerPoint slide show and automatically closes after the presentation is complete. These files are for presentations only and do not allow any editing. Conversely, .ppt files open in PowerPoint and allow the user to edit and make changes to the presentation slides. Converting a .pps file to a .ppt file is quite simple, does not require any special software and takes just a few minutes to complete with Microsoft PowerPoint

Instructions

• Make sure the .pps file is saved on your computer in a location that you know how to access easily.
• Open Microsoft PowerPoint. PowerPoint is usually found by accessing the "Start" menu and selecting "All Programs," and then the "Microsoft Office" folder.
• In PowerPoint, go to the "File" menu and select "Open" from the drop-down list. A prompt will appear, asking you which file to open. Browse to the location of the saved .pps file and click the "Open" button.
• From the "File" menu, select "Save As." In the "Save as type" box select "Presentation" from the drop-down list. Choose where you would like to save the .pps file and click the "Save" button. The original .pps file has now been saved to your computer as a .ppt file.

Tips & Warnings

• Those who do not have Microsoft PowerPoint installed can still view .pps slide shows by installing the free Office PowerPoint Viewer from Microsoft.

Simple Solutions to Common Windows Problems

Learn about some free software utilities that will help you fix the most common Windows problems. They are all compatible with Windows XP, Vista and Windows 7.

Fix Windows Problems with Free Tools

Q1. I am trying to delete a file from my desktop but the computer won’t let me do that. Instead, it throws me an error message saying that the file /folder is in use by another program or user.

A: You can either reboot your computer in Safe mode to delete that file or, if you want something more simple, get Unlocker. It’s a free utility that will let you close all the processes that have possibly locked the file and once they are closed, you can then safely delete the file.

Q2. I am trying to play a video file on my computer but the media player says that I am missing certain codecs.

A: You can use a tool like Video Inspector to determine which audio and video codecs are required to play the video file on your computer. Alternatively, you can download a codec package like the K-Lite Pack that will let you play virtually any audio and video format on your computer.

Q3. I am running out of disk space on my Windows computer. How can I remove all the unnecessary files from the computer and recover some disk space?

A: There are three things you can do here:

• Open the Run box and type “cleanmgr” to open the built-in Disk Cleanup utility. It will remove all the temp files and the unnecessary system files that you no longer need.
• Use WinDirStat to determine where all your disk space has gone. Sometimes files are hidden in sub-directories that you can safely move to other drives or even delete them permanently (more options).
• Use Duplicate Cleaner to identify and delete all the duplicate files on your hard drives. You can move the duplicates to the recycle bin or, if you want to play safe, to any another folder from where they can be easily recovered.

Q4. My computer takes lot of time to boot-up. I checked the “start-up” folder in the Windows start menu and there aren’t any applications out there.

A:  Type “msconfig” in the Run box to open the “System Configuration” tool and then switch to the “Start-up” tab. Disable all the programs that you don’t need to run during start-up. If you are a power user, you may also switch to the “Services” tab and disable all the unnecessary services.

Autoruns is another excellent utility that shows you what programs are configured to run during system bootup or login.

Q5. I am trying to uninstall a program from my computer but the standard add-remove programs is not letting me through.

A: You can use the free Revo Uninstaller utility to remove every single trace of any program from your computer. Revo can also remove entries from the Windows Registry that may have been left by previous un-installation routines.

Q6. My Windows crashed with a “Blue Screen.” Why?

A: You really need to get in touch with a geek to debug the cryptic Blue Screen errors (aka “Blue Screen of Death”) but if you are lucky, a free utility called BlueScreenView can provide vital clues. Blue Screen View will scan the Windows dump files to determine the device drivers that possibly caused the crash.

Q7. It takes ages to copy files in Windows from one folder to another. The situation is marginally better in Windows 7 (over Vista) but still, is there a way to copy files faster?

A: You can use an external file copying utility like TeraCopy or even RichCopy – they’ll not only copy /move files across drives faster but you can also resume broken file transfers (similiar to FTP operations).

Q8. I think I deleted a file by mistake. Can I recover it?

A: Recuva is a free software that will scan your hard drives, USB stick and other external drives for any deleted files that it can possibly recover. It may not work in all cases especially when you securely deleted a file.

Q9. Every time I copy something new to the Windows clipboard, the previous content gets erased. Can I make it permanent?

A: You can use Ditto, a free utility that sort-of adds memory to your Windows Clipboard. You can copy anything to the clipboard and it will stay there as long as you want.

Q10. How do I protect files and folders on my computer?

A: While there are free tools like Hide Folder that let you easily protect files and folders with a password, use TrueCrypt if you want a more secure solution. The obvious downside with a program like TrueCrypt is that if you forget the password, it is nearly impossible to retrieve the protected files. 

Access Files on your Computer from Anywhere

The problem: You have documents, photos, music and other important files on the home computer. How can you “remotely access” these files from your office computer or, when you are travelling, from your mobile phone?

The solution: The simplest solution would be that you copy all your data from the home computer on to a portable hard drive and carry it around but this is obviously a bit cumbersome approach as it requires you to manually sync the home computer and your portable disk.

Access Files on your Computer over the Internet

There are couple of ways by which you can retrieve files stored on your home computer from anywhere else using a regular Internet connection.

Option 1: Using Online Backup

You can use an online backup service like SugarSync, Carbonite, SkyDrive or even Dropbox – they provide desktop utilities that will automatically upload files on your home computer to the Internet and you can then access these files through the web browser of any other Internet connected computer.

The upside is that your files will always be available to you even if the home computer is not running. SugarSync and Carbonite have a mobile optimized website so you can access files from any mobile phone as  well.

The downside is that if you are using any of these services for the first time, you’ll to wait until they upload all your data to the cloud and this process may take long if you have too many files on the home computer.

Option 2: Using Desktop Sharing Software

There are free desktop sharing software like TeamViewer and UltraVNC that also let you remotely access your computer files from anywhere else. LogMeIn Pro and CrossLoop Home are some other good options for transferring files from a remote computer but these are paid services.

If all your computers are running Windows, you can use the built-in remote desktop connection feature of Windows (available in XP and later) to access your home computer from another Window computer over the Internet.

With Desktop Sharing software, you’ll always have access to all your files but one big limitation is that it requires that the remote computer stays on. Also, none of these options will help you access files on a mobile phone except LogMeIn which has an iPhone app.

Option 3: Access Files Directly through the Browser

Online backup services, discussed above, will copy files to their own servers before you can access them for anywhere else. Screen sharing services are often slow and they won’t work on most mobile devices. Let’s now explore another set of services that allow you download files directly from the home computer.

Copernic, like Google Desktop, is a popular desktop search software that you may use to find emails, documents and other files on your Windows computer. They have a paid component called myCopernic on the Go that lets you remotely search for content stored on the home or office computer. You can preview the search results and then download them to your mobile phone or remote PC.

With Opera Unite, you can easily turn your computer into a web server and instantly access files and folders on that computer from any other web browser (including that of mobile phones). Opera Unite is a standard web server and therefore you’ll be downloading files directly from the computer – they’re not uploaded anywhere else.

Another option is GBridge that lets you setup a virtual private network using your existing Google Account. Companies use VPNs to let employees access corporate data over a public network (Internet) and with GBridge, even home users can build their own VPNs to access remote files more securely.

Windows Live Sync at sync.live.com is another great choice for remotely accessing files over the Internet. Just install the Live Sync client on your computer and you can then access the entire hard drive of that computer simply through the Windows Live Sync website.

Live Sync is available for both Mac and Windows. The new version of Live Sync is even better and it has integrated online storage (Live Mesh) so you’ll be able to access your important file even if the remote computer is off.

Finally, you may also want to check out HomePipe – this is an extremely easy and free service that lets you access your home files and media from any other computer or mobile phone. Install the HomePipe Agent and all files on that computer will instantly become available through the web. They also have apps for iPhone and Android phones.