Abstract: The idea of Skype is to have a self-maintaining network of users, who can communicate with each other by voice just as they would communicate using an instant messenger.
Skype Reviewed - Kazaa`s Voice over IP Calling
It is likely that almost all computer users are familiar with email, and probably instant messaging as well. In a matter of a few years, the Internet has completely changed the way we communicate with each other, with one exception, the Telephone. Nothing has yet replaced the ritual of picking up the phone and dialing a number to have a conversation, and it's unlikely that anything ever will replace voice communication the way that email has erased hand written letters. However, the Internet does provide possibilities for making the calling process more flexible, and most importantly, more affordable. Today we are going to look at Skype, an Internet Phone application currently going through a free beta-test, and generating a lot of buzz. We'll also examine how Internet telephony works, and why you should care. It's been said that Internet based voice calling will replace traditional telephone networks, the only question being how long it will take. Skype could be one of the applications that make this a reality. VoIP crash course Voice Over IP is the process of transmitting voice communications, like phone conversations, over an IP based network like the Internet. It uses IP addresses instead of phone numbers, and Ethernet cable in place of phone wire. VoIP can performed by an application like Skype, or a device like an IP phone. The major difference between IP based voice communication and the telephone network we are all accustomed to using is the method of sending data. Both methods convert sound to electrical signals (data) and send it over a network to the recipient, where it is converted back. The networks they are sending data over are vastly different, however. A Public Switched Telephone Network (PSTN), our standard phone system, forms a circuit between the caller and the callee which stays connected for the duration of the call. IP calling uses the Internet, a packet-based network. This means that data is transferred in discrete packets which are sent from source to destination independently and assembled when they get there. This is more efficient and much less subject to distance issues than a PSTN. This is half the reason why VoIP calls are so much cheaper than PSTN calls. The other half is the fact that the Internet is more or less globally maintained, whereas phone systems are implemented and maintained by individual governments and corporations. So while you and your phone company need to pay for the right to use a remote phone system to connect, there is no such need on the Internet. Once you are on it, you can send data without restriction or cost.  So free phone calls for everyone right?
Hold on a sec. VoIP programs like Skype have the run of the Internet, and no one is trying to charge long distance rates for that (at least not yet), but there's a bit of a snag when it comes to regular phones. See, regular phones are connected to regular phone lines which are administered by regular phone companies who would like regular payment for their services, thank you very much. Understandably, the company you pay for your telephone access is not overly keen on the idea of you being able to dial up anyone, anywhere in the world, for free. They don't have much to worry about though... In order to bridge a call started on the Internet (via a VoIP application or phone) through to PSTN (Public Switched Telephone Network) phone, a special connection device is needed to bridge the gap between the packet-based Internet and the circuit-based telephone network. The VoIP Gateway is a device that connects and translates the Internet and a regulation phone line. A user makes a local phone call or a VoIP call to the gateway, which then transfers the call over the Internet to a second gateway which dumps it back onto the regular phone system at that location. In this way, long distance charges can be circumvented, and regular phones used to call computer systems and vice versa. However, while these VoIP Gateways are available, they are not yet at a cost or a simplicity that would make them desirable for home users. Also, in order to use them effectively, you need a gateway at every location you intend to call regular phones at. This is expensive and complicated, which explains why full global VoIP calling is still the domain of major corporations and institutions that can afford the initial expenditure required to set up a VoIP network. VoIP is becoming more common internally, within large institutions like college campuses. There it provides an effective means of communicating within the campus grounds, requiring only an interface to the regular telephone system to ensure that any calls out are transferred to that network. To sum up, things get complicated when you start thinking about calling from your computer to someone else's phone. As long as you keep things strictly Internet-based though, there's no extra cost incurred, paving the way for services like Skype. What is Skype? Founded in August of last year by the brain trust behind the (in)famous Kazaa peer-to-peer file-sharing program, Skype is touted as being the first true peer-to-peer telephony program. Essentially, the technology that made Kazaa so successful (and difficult to sue) is being used to power voice communication over the Internet. What makes this method distinct is that it lacks a central 'server' containing user data and connection information. Each system running Skype becomes a node in a vast network of Skype users, who share the necessary database information required to keep each user informed of who is online at any given moment. Calls may also be routed through other Skype 'nodes' when direct communication is unfeasible. The idea of Skype is to have a self-maintaining network of users, who can communicate with each other by voice just as they would communicate using an instant messenger program like ICQ. Distance and location are irrelevant as long as you are connected to the Internet. There are no costs or time limitations attached to calling. You have 'buddy' lists just like ICQ or MSN, and can search the Skype database for people to contact. The makers of Skype also tout its ability to pass through conventional firewall devices and applications mostly unscathed, a feat which has given pause to previous VoIP software applications. While the Skype site is not too forthcoming about how this is accomplished, it seems to use much the same method as recent Kazaa implementations. In other words, it uses a dynamic assortment of TCP ports to connect and send data, falling back on port 80 (the standard HTTP port used to connect to web servers) if it is blocked elsewhere. The software uses a single UDP port (or port 80 again) to listen for incoming data. While Kazaa's ability to negotiate firewall security has made it a scourge to company sysadmins everywhere, Skype promises to use the technology for a much more beneficial purpose: user friendliness.  How many people have firewalls built into their home Internet sharing devices and have no idea how to configure them? A lot. And once Service pack 2 for Windows XP is released, factor every single Windows XP user into the equation, since the XP firewall will be enabled by default by the service pack.
Several previous VoIP implementations have been handicapped by their dependence on a static set of ports which are often blocked by default with the average firewall. While these ports can be opened, most users may not have the desire to get this technical. As we said, Skype is still in beta testing. The manufacturers have stated that while they intend to keep the core service free after it clears beta testing (though no doubt ad subsidized), they will offer premium memberships with perks like conference calling (currently free in the beta) and voice boxes that would be desired by a more business oriented user base. There is a general move towards VoIP solutions in the market, with some suggestions that Microsoft will integrate VoIP into its next Windows version, or release a product or add-on even sooner. Let's take a look at using Skype: Installation Installation of the Skype Beta echoes the procedure for every recent instant messaging program we have tried. It's a painless procedure, requiring only that you create a username and password and fill out as much of a personal profile as you choose. That's really all there is to it. 
Beginning users might have a few issues outside the program itself however, given the propensity of Windows to disable and mute the microphone input by default. This can make voice communication rather difficult. Let's have a quick look at how to make sure your microphone jack is not muted so you can use a headset properly:
Go to 'start\all programs\accessories\entertainment\volume control.' Now select the 'options' menu and choose 'properties.' 
From this window, scroll down until you find the 'Microphone' entry. Ensure that it is checked and click 'ok.' Back in the volume control window, make sure that the 'mute' option is unchecked for the 'microphone' section. From here you can also adjust the volume and gain of the mic. The Skype Interface Used ICQ or MSN Messenger? Then you'll know what to expect. The Skype interface mirrors these programs most, and why not, considering it's also an instant messaging client. 
The 'start' screen shows any missed calls along with the username of the caller, and how many of your contacts are currently online. The 'search for Skype users' option allows you to find your friends and add them to your contacts list. The 'contacts' tab, as you'd expect, lists your contacts ordered by whether they are online or off. 
The 'calls' tab lists all phone calls made and received by you, and can be filtered by contacts and call direction. 
The big green call button at the bottom of the screen will dial whichever contact you have selected, and the adjacent hang up button ends the call with a satisfying click. When a Skype user calls you, the call screen comes up to indicate who is calling, along with a very convincing ring effect. You can choose to answer or send a busy signal (GO AWAY!). Blocking of contacts is also supported and prevents them from calling or Instant messaging you. The Skype system suffers from some delays in updating the status of users. While playing around with blocking contacts and going offline for short periods, we found that the status of the user took about five minutes or longer to update on other systems. Testing Skype In use  For a first test, we set up a couple of computers across the room from each other, hooked them up to separate DSL Internet connections and installed Skype on both. After creating a couple of users, we searched for one of the accounts and requested an 'authorization' which would allow us to see when they are online.
We promptly authorized both accounts to each other and proceeded to call and chat... The whole setup process took less than five minutes from start to finish. So far so good, but how does the call quality sound? It's a mixed bag. While the voices were clear and crisp through our headsets with Skype, things get muddy very quickly when two people try to talk at once. Generally you just cut in louder than the person on the other end of the line, and we heard static and various strange clipping effects once we started singing duets (not really surprising, it happens to me in karaoke too). Still, once we figured out that talking in unison doesn't really work, the experience was positive. Move your calls out of the same room, to say a continent or so away and it's darn good. For long distance calls that cost nothing per minute, it seems even better.  Next we tested out Skype's echo service, a username ('echo123') that they have set up to allow users to test the sound quality of their connection. It records a ten-second snippet of your voice and plays it back to you. No problems here, sound was clear and crisp, so the issues seem to be only when parties try to talk over each other. After this, we started in with some International calls. First to San Francisco, then London, England. Then finally Belgium. The sound was actually much better on all of these calls. So much better in fact, that I'd say it was perfect, except for the aforementioned distortions when both parties try to talk at once. Very impressive.  Skype also offers an instant messaging feature which works in unison with the VoIP aspect of the program. Right click a contact or the icon of the person you are talking to and select 'send an instant message' to open the instant messaging screen.
By default, the Skype instant messages are fully encrypted and are logged on your computer, accessible from a button on the toolbar. As a nice touch, all messages you have recently exchanged with a particular contact stay visible in the instant messaging window for that contact, even if you close it and reopen it later. Unfortunately, there is no 'message waiting' ability as seen in ICQ. Messages sent to an offline user will not be received by them when they log on. Unsurprising given the P2P structure of Skype. Overall, we found the instant messaging feature of Skype effective and easy to use, with one large and rather annoying exception: it is difficult to actually notice when one of your contacts has instant messaged you. The options menu includes four notification options for this purpose. Three of these are enabled by default, but only two seem to work, and of these two, only one is useful and predictably, it's the one that's off by default. Apparently Skype is supposed to play a sound and flash the icon of the contact that is messaging you. It did neither on our two test systems. It does open a chat window, but very stealthily. Without the flashing that accompanies other minimized instant messaging programs like MSN Messenger, it's hard to notice the new window at all. The useful, disabled-by-default option gives you a text bubble each time your contact messages you, which works well. Leaping to Early Conclusions As it stands, it's hard not to like Skype. It works, and works well even in beta, and as a result of its current beta status it's also ad and spyware free. More importantly, it's easy to use. While we were in process of a call with Skype, we generally saw CPU usage around 20-25% - not too bad. This should mean that Skype will be a viable tool for gamers to communicate by voice while playing their favourite online games. Anyone who has a casual acquaintance with any instant messaging client will feel right at home making VoIP phone calls with Skype. Obviously a headset is required to get anything out of the program, but this is a fairly trivial investment. The Skype software has a few rough edges, which we detailed, but is admirably economical with system resources. Give it a try, and say "hi" to those long-distance relatives! © 2004 PCstats.com
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