An application server (AS) provides services to end users and allows new functionality to be added to an IMS core. It acts as a SIP endpoint and can behave like a user agent, proxy, redirect server, or back-to-back user agent. Examples of ASs include those for presence, conferencing, text-to-speech apps, billing, and IVRs. An AS is configured by setting up initial filter criteria, the AS definition, and trigger points. It can be built with options like JSSIP, Asterisk, FreeSWITCH, or Mobicents. For example, an AS was created to serve as a conferencing room supporting audio/video, various transports, and codecs by searching for an

1. An Introduction to
IMS Application Servers
Carlos Ruiz Díaz

2. 1. a component that provides services to the end user
2. the natural way of adding new functionality to an IMS core
3. a SIP end point, most of the time
1. a component that provides services to the end user
2. the natural way of adding new functionality to an IMS core
3. a SIP end point, most of the time
What is an Application Server (AS)?

3. 1. User Agent (both originating and terminating)
2. SIP Proxy
3. SIP redirect server
4. SIP B2BUA
1. User Agent (both originating and terminating)
2. SIP Proxy
3. SIP redirect server
4. SIP B2BUA
How does an AS behave?

4. 1. Presence
2. Conference bridges
3. Text to Speech Apps
4. Billing apps
5. IVRs
6. etc.
1. Presence
2. Conference bridges
3. Text to Speech Apps
4. Billing apps
5. IVRs
6. etc.
Examples of Application Servers

5. Where do I plug my AS?

6. Where do I plug my AS?
Here

7. Application Server triggering
User Profile

8. Basic IMS call flow

9. Set up...
1. ... the Initial Filter Criteria
2. ... the AS definition
3. ... the Trigger Point
Set up...
1. ... the Initial Filter Criteria
2. ... the AS definition
3. ... the Trigger Point
How can I configure one? (in summary)

10. Real-world configuration example

11. What can I use to build an AS?
Text description
JSSIP
Asterisk
FreeSWITCH
Mobicents
Some options out there

12. Creation of an AS with the following characteristics:
- Serve as a conference room
- Accept Audio/Video Calls
- Support TCP/TLS/UDP/WS transports
- Support most common audio/video codecs
Creation of an AS with the following characteristics:
- Serve as a conference room
- Accept Audio/Video Calls
- Support TCP/TLS/UDP/WS transports
- Support most common audio/video codecs
Practical Example

13. 1. We searched for an open-source conference server
2. We filtered options
3. We put Kamailio in front of it to make it work better
1. We searched for an open-source conference server
2. We filtered options
3. We put Kamailio in front of it to make it work better
How we did it?

14. And the result was this...

15. 1. Application Servers are extremely useful
2. They are fairly easy to build
3. You don't have to be an IMS expert to do it
4. You probably know already how to build one :-)
1. Application Servers are extremely useful
2. They are fairly easy to build
3. You don't have to be an IMS expert to do it
4. You probably know already how to build one :-)
In conclusion

16. Thank you!Thank you!
Questions?
@caruizdiaz linkedin.com/in/caruizdiazcarlos@ng-voice.com