Thursday, May 10, 2007

Standardization of IMS

Well I have made it back from Vacation. Mickey has taken all my money so now it is time to get back to work. I have to admit it was a great time with my family and the weather was perfect. But not to digress from the real topic here. Today we are going to discuss who is driving IMS and what standards bodies are working on IMS.

As most of you probably already know there are standards bodies for everything in telecommunications and data communications. So if IMS is suppose to span all technologies and networks then how are standards being set. To understand this we will start were IMS started. The first standard body we need to look at is the ITU(International Telecommunication Union). The ITU created IMT-2000(International Mobile Telecommunications-2000) which is the global standard for 3G network. A collaboration of standards bodies make up the the IMT-2000. Inside the IMT-2000 there are two standards bodies that are the main focus for IMS: 3GPP(Third Generation Partnership Project) and 3GPP2. 3GPP delas with UMTS networks and 3GPP2 deals with CDMA networks. Both have created standards for IMS, but most will refer to the 3GPP standards. There are other groups in IMT-2000 working on IMS, but these two groups are the main focus of IMS. 3GPP introduced packet switched voice services in a standard called R4. IMS was introduced in standards R5/R6.

In R5 the standard calls for the use of SIP and IP has a basis for IMS. Hence this is were the IETF(Internet Engineering Task Force) comes in to play. IETF is responsible for SIP and other IP protocols. SIP is a good protocol but needed to be extended to fit the 3GPP needs. So 3GPP and IETF started working on extending the standards for SIP.

At the same time other groups like CableLabs(Cable Companies standards) started defining IMS support in DOCSIS(Data over Cable Services Interface Specification) 2.0. Also wireline groups ETSI(European Telecommunications Standards Institute) TISPAN(Telecoms & Internet converged Services & Protocols for Advanced Networks) defining (EMEA) wireline extensions to IMS. For North Ameica, ATIS(Alliance for Telecommunications Industry Solutions) is developing IMS specs for NA market.

As you can imagine these groups all have special needs of SIP and this also gets pushed back into the IETF. Within the IETF, there are working groups that have areas. One of the areas was SIP. Once IMS chose SIP has a basis it became clear that the SIP group was going to be over worked. So to help with the problem the IETF created a new working group call SIPPING. The purpose of SIPPING is to gather SIP requirements from all areas and prioritize work before it goes to the SIP working group.

I have given a brief of descriptions and standards bodies and their roles in IMS. There is one more body that I would like to mention. Even though this group does not define any IMS specification it does deal with applications that will ride on top of the IMS architecture. This group is OMA(Open Mobile Alliance). To date they have defined Push to Talk and IM for IMS architectures.

Hopefully this has been helpful in understanding all the different industries and standards bodies that are working on IMS. I have include a diagram below to summarize this topic. Below the diagram I have also listed links to the various standards bodies.

Standards Bodies Links

Monday, April 30, 2007

Going on Vacation

Just wanted to let everyone know that I will be on vacation this week. I'm headed to the wonderful world of Disney. Since I will be enjoying the theme parks and the water parks I will not have time to post. But I will give you a quick preview of what I will be posting next week.

First we will look at who is driving IMS. And what I mean by that what standards and industries. One of the cool things about IMS it is not just Telco's, Wireless providers or MSO's. Then you have the IP goes of the IETF. All of these groups need to come to a common ground for IMS to work. IMS goes across the every type of network and industry. As you know each group in the past has had their on standards bodies. I will explain how these standards bodies are working together. We will also look at the rapid changes in standards.

Next we will look at the market place. I will discuss the state of the market and talk about how real IMS is today. We will determine what is hype, what is real, and when will a large scale deployment be available. I will also discuss applications and some of the major players in IMS.

Until next week, everyone have a good one.

Tuesday, April 24, 2007

IMS Basics

So here we go. We will start to dive into the mystical world of IMS. Just getting the basic understanding of IMS can be tough. If you have ever looked at a diagram of IMS you will know what I'm talking about. There are a lot of blocks on the diagram and a lot of lines with different acronyms on those lines.

Let's first dissect the name IMS - IP Multimedia Subsystem. What does it mean. First lets look at IP. Everyone knows that IP stands for Internet Protocol. IP is that bases for the Internet today. So by using the term IP, those who have created IMS have decided to use IP as the bases of IMS. Second lets examine the word Multimedia. I remember when I first started in the business and IP was just gaining momentum, Vinton G. Cerf, VP and Chief Internet Evangelist at Google wore a shirt to an IETF meeting that read "IP on Everything". Well in IMS that might become a reality. The term Multimedia was chosen because IMS was created to run anything over IP. That would include, voice, video, IM, Gaming and what ever else we have not even thought about yet. Okay far we have determined that the creators of IMS want to use IP and be able to run any service over it. The final word is Subsystem. This is a key word to understanding IMS. It took me a couple of tries to understand the importance of Subsystem. The definition of Subsystem is Something that is part of a larger system. So if IMS is part of a larger system what is IMS and what is the larger system. This is were I have seen people get confused about IMS. So get ready, here is the first important step to understand what IMS is. IMS is a network Architecture. IMS does not define applications or services, but provides an architecture that allows applications and services to be provided. an analogue that I like to use is a PC. The PC is not the application, it allows applications like Excel, Word or Internet browser to run.

So if IMS is just a network Architecture designed for IP multimedia applications, then you might ask what is all the fuss about IMS and don't networks today allow that. And the answer would be Yes they do. The difference is that today the networks are individual networks. The MSO network, the Telco network and the wireless networks. What IMS brings to the table is the ability to be network independent. So no matter were you are you should have access to any service or application. This is also called mobility and presences. I will dive into more details about the applications and the market timing in a later post.

To keep on track the purpose of this post is just to get a basic understanding of IMS. So let's take a look at an IMS diagram. As you can see in the diagram below there are a lot of blocks and lines in the diagram.
When I first looked at this diagram, I was totally confused and thought that IMS was the most complicated thing I had ever seen. This is because I did not understand the basics concepts of IMS and the philosophy that went into the design of IMS. First thing that we must understand is that IMS was created to be scalable. Since it is meant to be scalable the design and the diagram to the left is done on a function level. For me when I first looked at the IMS diagram, I just immediately assumed that all the boxes were actual Network Elements/hardware. That is not correct. There is nothing to say that you could not have multiple functions in a single piece of hardware. Another thing that has help me in understanding IMS is this, there are really only two components of IMS.

They are the Core and the peripherals. As you can see from the diagram that the core is actually made up of some basic components. The components are the Call/Session Control function (CSCF) and the Home Subscriber Server (HSS) and SLF(Subscription Locator Function) databases. This is the foundation in which the IMS architecture is created around.

So that is all for today. Hopefully the following points have been made through this posting.
1) IMS is an architecture. It is not a single product, application or service. The architecture is based on IP.
2) IMS provides a means for mobility and presence and is network access independent.
3) IMS diagrams call out functions and not individual devices or pieces of hardware.
4) A simplified look at IMS is that there are two components. The Core and the peripheral.

In upcoming post we will start to dissect the architecture and the communication/protocols between functions in more details and we will also start talking about applications and the market drivers.

Until next time have a good one.

Monday, April 23, 2007

Getting Started with IMS

My first post will be to introduce myself and the purpose of this blog. So to get started I would like to introduce myself. I'm Jay Stewart. I'm currently CTO of a startup company. I have been in test and measurement of IP networks for close to 20 years now. Wow, having said that I realize how old I'm getting. Anyway, I have worked with Ethernet, Token Ring, FDDI, ATM, HSSI, T1 and yes even VGAnyLAN. That's right VGAnyLAN. Does anyone even remember that one. I have also worked on VoIP, IPTV, Metro Ethernet and now IMS(IP Multimedia Subsytem).

Which brings me to the reason for this blog. I started looking into IMS about 6 months ago. I have a lot of experience into the IP industry and I know that with this industry there comes what I call the Hype wave. After about 12 months of that the reality phase might come. I have been trying to understand what is IMS, Why IMS and will IMS become a reality. Having worked through this the last 6 months I have come to one conclusion. That conclusion is that I haven't been able to find any straight answers to any of those questions. Depending on who you talk to and the industry they represent you might get many different answers.

Hopefully through this blog I will be able to help people step through the IMS web easier then I have been able to. I hope to explain what IMS is, or as at least explain all the new acronyms. What is real and not real in IMS today and some of the time lines for IMS.

I'm also working with several people from other companies in the IMS arena that are experiencing the same issues. So I will be using them as references for this blog. If you have any areas of interest you would like for me to cover please let me know. I will try to cover to the best of my knowledge.

We are currently setting up an IMS lab and hopefully will be online by the end of April. I will be updating lessons learned on this experience, which could be quite a few.

Thanks for reading and looking forward to sharing and learning with you.