Let me offer a brief history of the topic and then I will give my view on where technology is headed including how IMS fits in. There are people who just operate, we call them technicians, there are people who design hence architect, and then there are people who engineer. An engineer is not a guy who sits and designs. An engineer is a thinker; a philosopher of sorts who learns how things are designed and either makes them better or knows the little pieces enough to reproduce. Engineers implement, integrate, and improve technology. The world is full of technicians.
In knowing this, if you are sitting next to a computer today and haven’t even thought about how you connect to the Internet, then you are not an engineer. If you are working in IT then you shouldn’t even have the initials “eng” next to your name.
Remember the dial-up days when you had to have that AOL account, and yes I had an AOL account, and they would give you access numbers out of the kazoo to make you think their presence was “everywhere”? Cool trick. Sadly this was not true, but it did mark the beginning of IP convergence.
AOL was not the first, I want to say CompuServe was the first, but honestly I can’t remember because AOL dominated the market for so long. And that Genius Steve Case was shrewd enough to orchestrate a merger with Time Warner when it was on the down swing. Brilliant!
This trick was accomplished by connecting your home PC to a phone line. You clicked your little icon which was actually a PPP client. This sent your authentication to a modem, which would convert you back to layer 2 (PPP). Now here is the tricky part: most of those modems didn’t actually belong to AOL, they belonged to a guy who worked in his home and provided internet connectivity to the web using a T1 or higher. They, meaning those who provided modem connectivity from their basements, were cheap so they didn’t care about your bandwidth concerns. For authentication, your domain name, “@aol.com” would point you to an AOL Radius server where your username and password were authenticated. Simple isn’t it?
This was great until users and websites demanded something higher than 56kbps and the emergence of mobile users and lazy executives drove the need for more bandwidth. Enter the world of DSL. What made DSL a great option was the fact that it shared the same simple wire as your regular telephone so the last mile was already pre-established.
With DSL came the DSLAM, which terminated connections and could authenticate sessions. The only problem with the DSLAM was security. Converting users from a L1 to a L2 meant that it would authenticate users and allow them to ride one L2 segment. This is unsecured. Authentication was moved back a layer so that the existing PPP sessions were left untouched and unauthenticated, which gave way to PPPoa (over ATM) and PPPoe (over Ethernet). Another breakthrough in technology, meaning users are authenticated and routed via VLAN’s and SVI interfaces. The establishment of a L3 boundary closer to the source meant policy routing and more security. It also meant provisioning could be performed, such as QOS and other services, on a collocated equipment basis. Meaning Corp A or SP A could get a L2 handoff from the acting Carrier equipment and handle it’s subscribers as they wished. So this is the end, you are now on the internet. Easy, huh? Well, I needed to explain that little piece before I can get into the advanced stuff.
This type of connectivity only handles physical connections such as DSL, cable access, and phone lines. What about wireless? The need for a standard has been out there for a while – the need for having converged authentication for voice, video, and data. 3G was supposed to be the savior for all of this, but along the way the IMS standard was developed and connecting a mobile phone to the Internet will be the same as connecting a home PC to the Internet.
Where is technology going and how much can it converge? Well it can converge down to the physical medium. The physical medium of choice will soon be wireless. Currently we have 802.11 growing like wildfire. Many organizations are learning that it is cheaper to provide a wireless nic and AP’s than it is to maintain wiring. It is cheaper to buy 802.11 capable phones than it is to provide phone wiring and wiring closets to house the phones. And that is just indoors. With the emergence of WIMAX, soon whole towns, states and even regions will be lit using the same towers that provides Cellular service.
Can you imagine maintaining an 802.11 call from your house, to your car, and into your work? Of course not, that is the beauty of it all. Can you imagine moving into a new house and calling to get internet connectivity and all it takes is a wireless router you can buy from Circuit city to provide you 70 Mbps/70 Mbps? That is more than I am getting via wired connection.
Now how will all of these technologies meet? To answer would be the IMS standards. IMS is an architecture to converge Voice and Video along wireless techonologies. Meaning Cellular (3G and GSM), WiMax and WiFi.
VOIP subscriber logs in. VOIP/Sip user is Derek@myprovider.net. The user connects to the Internet and is registered and authenticated to his domain via the web. This connection can be provided by any service provider. The same server can authenticate a data user with the same login. Billing is performed and with the IMS standard all components are similar so CDR (billing) is uniform throughout the whole process.
IMS is a necessity because it conforms the standard for not just voice. That means it answers the roaming questions for both voice and data. If I am a mobile user on an 802.11 network and I roam outside, what will happen to my connection? Your session can continue and IP mobility can handle authentication in the background. The session can exist transparent to the user.
The same goes for 802.11 to Cellular service, which could transparently handoff data and voice sessions no matter who the service provider is. All subscribers would be routed to their provider’s Hss for authentication using the Diagram protocol. All routing would take place via the global ENUM services.
Think about it, don’t just live it. Ten years ago I purchased an 18 gig hard drive for over $1000. Today I can buy one about the size of my keychain for $79.99. Ten years ago I was using a 56kbps connection and thought it was the greatest thing since Don King’s fro, now I am complaining that a 5 gig download takes too long over a 1 Meg connection.
IMS is the future. Talking on a reduced cost VOIP phone on your neighbor’s wireless LAN then going home continuing the same call through the power of seamless IP mobility, 802.11 to cellular to 802.11 in one call. Downloading a large document, while driving from Wyoming to Canada and going through three different IPS or cell carriers without having to restart the download. On the carrier side, to having billing fully work for each of the individual carriers is a major accomplishment. The future is today and tomorrow is going to be a pleasure to watch.