Monday, March 3, 2008

An Article from Microsoft

Joseph Hofstader, an architect at Microsoft who writes periodically on Telecommunications technologies, sent to me a link to an article he published on Communications as a Service (CaaS). This is the first in a series of about 3 or 4 he has planned on the topic, diving deeper into architecture and infrastructure.

The article is very interesting, clearly describing the capabilities of SIP as a protocol, and the paradigm shift between the traditional concept of communication services and CaaS.

Concerning the IMS related part of the article, readers of The IMS Lantern will understand that I would tend to elaborate more on the IMS service architecture and the unique benefits it can provide, but I understand that this is not the focus of Joe's article. He actually intends to elaborate more on this aspect in his next articles.



Anonymous said...

Hello Christophe,
i am student from Bosnia and Herzegovina and my english is not so well. :) Your blog is very interesting. I wanted to ask you if you can help me with some things. I have to finish my graduate work (i dont know how to call it) and i need to wrote something about "IMS over HSPA". Can you tell me where to find some literature about this? I have this books: "Convergence technologies for 3g networks, The 3G IP Multimedia Subsystem" but i need
something like - IMS over HSPA architecture or how to build IMS network over HSPA....

Anonymous said...

Dear Student,

The concept maybe difficult to get at first. Telecommunications networks are layered as Access Networks and Core Networks. IMS is a Core Network subsystem. An Access Network can be a wireless or wireline network. HSPA is an example of a wireless access network. The objective of the Access Network for a user equipment is primarily to provide the IP connectivity access network to the IMS Core. To a large extent IMS is independent of the access network. It is therefore referred to as being access agnostic. What this means is that whether you use HSPA, HSDPA, HSUPA, GPRS/EDGE, the core IMS architecture is not affected. The Edge Functions, as outlined in the 3GPP architecture will apply uniformly as you are considering only a different RF method. The edge functions imply the bearer handlers and Policy enforcement functions which would be the GGSN in this case. If on the contrary you would be thinking of LTE or WiMax (4G) for example, you would need to consider the SAE anchors or the ASN for the IMS edge bearer functions. The book that you have describes the common set of IMS principles that apply to 3G access networks. This will suffice.

Jack Chrysler said...

I tried this and it fits my needs.