Realize VoIP, January 2010

If you wish to subscribe or see other issues of our newsletter, you are invited to visit our Realize VoIP Newsletter homepage.

You can view this issue in the following languages: English | 中文 | 한국어 | 日本語

In This Issue

Editor's Note

By Amir Zmora, VP Marketing

SIP Beyond Telecom is the theme of this newsletter and the title of a webinar we held in November 2009. The Session Initiation Protocol was originally designed as an extensible protocol and as its name implies, for creating sessions. This capacity can be used for any purpose one of which is telecom. Other applications may vary including examples such as home automation and transportation. One of the common mechanisms used for such purposes is the SIP Specific Event Notification RFC 3265 and user defined events but since any SIP message may be extended through more headers and other elements; there is no real limit for the use of SIP.

This newsletter focuses on 3 main areas:

A review by Tsahi Levent-Levi on the SIP Events mechanism
Usage of SIP in the transportation vertical by Matan Barth
SIP Presence mechanism review by Sagi Subocki

In closure before you start your reading I would like to refer you to the section below asking for your opinion. We would be happy to receive your feedback in order to learn what topics interest you and which you would like us to write about in our future newsletters.

We Value Your Opinion

We would like to make it even better, so please share your opinions with us:

What do you like about our newsletter?
What do you dislike about it?
What would you like to see in future issues?

The best part is that you can let us know simply by replying to the newsletter email you received. You can also contact us through our community contact form.

Events Based Telephony

By Tsahi Levent-Levi, Project Director & Community Facilitator

Some say that presence is the new dial tone. This is a statement that goes back as far as 2006. While this hasn't yet happened everywhere, it is gaining ground in both desktops and mobile devices. What does that mean to telephony and VoIP from a technological point of view?

Traditional telephony used to care about dialing - how do you dial a call, signal availability of the user, establish the physical call connection to send the media and then bill the users. Essentially, the center of the system in such cases is the PBX.

Instant Messaging services changed that. They added a presence element, which was linked with instant messaging and later to voice and video calling. Presence was added by having multiple users publish their status to a central or distributed presence server, and listeners who subscribed to receive status notifications on users they were interested in.

In the context of SIP, presence is achieved by means of an Events mechanism. You can use PUBLISH messages to notify your status to an events server and SUSBCRIBE in order to tell an events server you are interested in notifications about an event, and then receive NOTIFY messages informing you of status changes.

Here's an illustration from a recent webinar I participated in along with Sasha Ruditsky, our CTO. Sasha used it to explain how the Events mechanism in SIP works. The Notifier is the events server, while Alice and Bob are users. Alice wants to know about Bob's status and gets notified whenever Bob publishes a change in his status.

SIP Events Mechanism

The beauty of this mechanism? It is not limited to presence. It can be used for a varied set of events, which can be totally unrelated to VoIP and telephony. This makes SIP quite useful to non-telecom applications.

SIP Beyond Telecom: Trains

By Matan Barth, Projects Manager

Train control and monitor are the heart of every Railway communication systems. These systems are mission critical communication systems which control locomotive and train movement and prevent disasters. Railroad operators today have started their migration to IP networks and IP based protocols.

Using SIP for human Voice and Video communication is common but trains communication introduces a new challenge. How to implement machine to machine communication?

You can think of a railway system as split into 3 types of entities:

Locomotives, where information such as fuel level, location and maintenance data is important
Wayside devices, such as traffic lights that monitor and control elements located on the rail side
Railway control center, where all information is received and processed from the various sources

SIP Events mechanism in service of railway communication

The SIP railway communication is based on using the SIP protocol to send information of 2 types:

Session based - a source and a destination are connected with a specific session
Publish - Subscribe mechanism (Pub-Sub) allows an entity to subscribe for receiving information published by another entity without being sent to it specifically by that entity and without establishing a connection with it

Each of the above mentioned railway entities is represented by one or more standard defined SIP logical entities:

Locomotive

Locomotive Sensors - SIP User Agents
On board Locomotive server - SIP back to back User Agent

Wayside devices

Wayside devices - SIP User Agents

Railway Control Center

Different servers are represented by: SIP Proxy, SIP Registrar, and SIP Application Server

Railway SIP communication network - concept (Norfolk Southern)

By supporting multiple communication concepts the SIP protocol is positioned to serve non-telecom IP based machine 2 machine communication systems such as Railroad, and many others.

In addition, SIP has other important benefits for the segment:

SIP extension easiness for adding headers, parameters and embedding foreign protocols inside its messages makes it flexible for use in non telecom oriented systems
Built in solutions for NAT traversal, security and Signaling compression are all creating a solution umbrella for next generation non-telecom communication systems

Presence Made Easy

By Sagi Subocki, Product Manager

Traditionally, communication between two sides is ad hoc and established via a call attempt, whether voice or voice with video. If the terminating side is not available, the call is dropped or redirected to a voice/video mail system.

One of the great enhancements of the traditional ad hoc communication process is the concept of Presence. Now, before a call is made, the originator can be made aware of the Presence State of the other party and his availability for accepting the call, thereby making the communication process that much more efficient. In addition to Presence, there are other mechanisms such as Instant Messages (Chat), which in some cases can be more efficient than the traditional voice call.

This makes presence more than what the basic events mechanism in SIP is designed for, which means that additional protocols are required. In essence, you can split the "presence as the new dial tone" mechanism into three separate modules:

Presence itself, where notifications are sent, collected and then published
Buddy lists, which can be stored remotely on the server
Instant messaging, capable of supporting not only text

How is this achieved in the context of SIP?

Presence is provided using the SIP events mechanism with a special presence package. Our implementation for it is the SIMPLE Client.
Buddy lists are defined by another protocol - XDM (XML Document Management), which is complementary to SIP.
Instant messaging is usually done with MSRP (Message Session Relay Protocol).
RTP for voice and video chats.

SIP based presence architecture

All of these three building blocks are available as part of our SIP Developer Suite.

Product News and Updates

Here with a number of new product releases:

We just released a new version of our ICE Stack, which provides TURN capabilities as well. This means you can now enjoy a full NAT Traversal solution for SIP.
Multimedia Terminal Framework version 4 was released. Among a large number of improvements, it contains two new add-ons: H.323 support and IMS support.

The new versions above are available to customers under maintenance agreements.

Blog Highlights

Enjoy this quick glance at some recent interesting blog posts on our blog network:

Makefiles: Ofer Goren deals with makefiles hell in Visual Studio versions.
Who said Twitter: While we delve around presence and dial tones, Sagee Ben-Zedeff views twitter as the Unified Communications of social networks.
Resources: Tsahi Levent-Levi published the compendium for the SIP Beyond Telecom webinar.

Here are two more posts that have interested our readers in the past two months:

With all the recent hype around smartphones and AppStores in 2009, you might want to consider where will future applications reside on mobile handsets.
Sagee shares his pick of posts from 2009 on our Video Over Enterprise blog.

We would also like to make you aware of an initiative we're running - a series of posts about designing hardware for HD video conferencing. You can follow it here.

In The Press

Octasic develops a mobile video gateway using our 3G-324M stack
MediaTek partners with RADVISION for 3G video telephony on mobile handsets
Learn more about vendors who are using our 3G-324M stack for their handset development
SCOPIA VC240, which uses BEEHD, won TMCnet's 2009 Unified Communications Excellence Award.

Webinars / Events

Where and When?

Date	Location	Event
February 2-4	Amsterdam	ISE 2010
March 10-11	London	UC Expo 2010

Meet us at ISE 2010

Interested in our high definition video client technologies? ISE might be the place to visit.

At Integrated Systems Europe (ISE) we will be happy to meet you and show our SCOPIA VC240 device at Samsung's booth (Hall 11, 11K38)

Meet us at UC Expo 2010

At UC Expo we will be happy to meet you at our booth to demonstrate our latest developments and products for the Unified Communications market (booth 502M).

Customer Satisfaction Survey

Your opinion matters to us. If you are (or were) a RADVISION customer of any of our developer tools, we would appreciate if you would complete our Customer Satisfaction Survey. It will only take a few minutes of your time and would help us a great deal. We will be leaving this survey open for you to fill in at your own leisure, but why wait? Take the survey now.

Past Webinar: SIP Beyond Telecom

SIP as an extensible protocol and with the general event-notification mechanism defined in RFC3265 as well as other activities in the IETF can be used for many purposes other than pure voice and video communications.

View our webinar online to learn how SIP can be utilized for non-telecom applications in varying industries and segments such as transportation, cars and medical.

Past Webinar: Carrier Grade IMS Developer Solutions from Core Network Infrastructure to Endpoint Devices

This web seminar reviews the challenges and opportunities of the development of next generation network elements. Speakers will discuss software building blocks, from the carrier grade open platform foundation to the underlying IP Multimedia Subsystem (IMS) for building infrastructure and endpoint devices.

View our webinar online to gain insight on a development trend to improve time-to-market through the adoption of a scalable common platform for multiple network elements.
(Presented jointly by RADVISION and Wind River)

Past Webinar: HD Video Conferencing to the Masses

High Definition video has become standard in most venues of media, yet it is still uncommon in video communications. Though the necessary technology is available, the complexity and cost of building an HD video solution is substantial. In RADVISION's online Webinar, you can learn how the RADVISION BEEHD offers the framework for developing economical HD video communication products while bypassing existing challenges. You are invited to register and view the Webinar online.

Past Webinar: Improving Video Quality in Your Network

While video deployment is experiencing a significant boom both in enterprise and carrier networks overall, the user experience does not always live up to expectations. In this Webinar, RADVISION experts discuss how to avoid pitfalls through pre- and post-deployment network assessment of video quality. If you didn't participate in this Webinar, you can now view it directly from the web. Registration is free.

In Closing

This newsletter aims to be useful to you. If you are not finding any value, PLEASE REPLY and tell us how we can improve. For more information from RADVISION, you are invited to follow the links below: