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Re: [MEDIACTRL] draft-ietf-mediactrl-mrb-01

Hi,
well if the mediactrl framework is fundamental to the MRB and I am the only one arguing against it then I guess I should stop that. The reason I started all of this was that in discussions with different customers we got the impression that the concept of MRB is a highly valued one however with no media servers supporting it at the moment the work done in the mediactrl WG with regard to the MRB is not applicable today.
While it is possible to move the discussion to some other WG we would end up having multiple places in which the MRB functionality is being discussed which is not really useful.
So maybe I should reformulate the discussion into: How can we deploy an MRB in an environment which is not 100% mediactrl compliant. Regardless of how simple or efficient the mediactrl protocol is, waiting till a media server is updated with this protocol is not an option. So instead of relying solely on the mediactrl framework as the basis for the communication with the MRB, it would be beneficial to allow other communication possibilities as well.
So how about having two MRB documents: one that describes what kind of information is exchanged over the publisher and consumer interfaces and one document describing the possible mechanisms for exchanging this information. 

Best regards
Dorgham

spromano at unina.it wrote:

Hi guys,
I think that the hypothesis that the MRB works in a mediactrl-enabled framework is a fundamental one. We all know that there are (non-interoperable) alternative solutions to the issues faced by the MRB; yet, we decided a long ago to stick to a much more focused approach which gives for granted that in the (hopefully near) future mediactrl components will be widely deployed. And that's also why we have always tried, inside mediactrl, to be both "fast" and "effective" (and I do believe that both objectives have been met ;-)).
This said, I see the interest in defining approaches which leverage legacy protocols/architectures, like the one proposed by Dorgham. What I don't see is that mediactrl is the right place where such approaches should be investigated. Perhaps this discussion might be forwarded to the DISPATCH mailing list? 

What is your feeling about this?

Cheers,

Simon

Quoting Dorgham Sisalem <sisalem at iptel.org>:


Hi Chris,

thanks for the reply. It seems that I unfortunately missed the
discussion but maybe we get another chance to go into the details in
the next meeting.
I still have some points though.
Chris Boulton wrote:

In my view using mediactrl at the MRB has many disadvantages:
- MRB Implementation complexity: The MRB will need to support the mdiactrl framework (yet another protocol beside HTTP and SIP)
[Chris] This is a not really true. This depends on the toolkit mode that you choose for your deployment. It is true to say that if you are deploying in IUMM or IAMM mode you do not need HTTP consumer interface and can just implement the control framework - which is light weight. The MRB toolkit provides the deployer with the options. 
I was actually referring to the need to implement the control framework
(which is not really light weight)
* The MRB will have to act as a UA. If the MRB was to act only as a
router between the application servers and the media servers then proxy
mode would have been sufficient
* All the control mechanisms of the media control framework
- MRB Statefullness: to establish media control channels with the media servers, the MRB will need to act as a UAS that will receive INVITE requests from media servers, establish a media control channel based on the SDP information and maintain the state of the channels.
[Chris] Correct - although I would see the MRB being the central management point for media servers and it would be making the connection in the opposite direction - 
how would the MRB know where all the media servers are?
- MS statefullness: The MS will need to act as SIP UAC and generate INVITE requests to the MRBs. This will unnecessarily increase the complexity of the implementation of the MS
[Chris] As mentioned previously, an MS could act as a UAC but so far the group has seen the MS in the role of a UAS (as it does today for SIP media dialogs etc) and the MRB being a central management entity. 
how would the MRB know the location of the MS then?
- All or nothing solution: The concept of MRB is very useful for establishing a division between the MS and application servers and can allow for simpler configuration and management of the large application platforms.
[Chris] The entire history behind the MediaCtrl group was to build on previous industry experience of protocols such as 'M*' and specify an appropriate solution moving forward. I belive the group has achieved this goal with its specification of the media control suite of protocols and is also heading in correct direction for the broker solution. Re-using the control framework is a natural fit for a media server that wishes to be MediaCtrl compliant.
[Chris] MediaCtrl based servers will be the de facto standard and so re-using the control framework re-uses a common interface to a Media Server. There are multiple mechanisms being used in the wild today to support such functions which is why a MediaCtrl solution must converge on one (just like we have with the M* protocols). Using the control framework provides the opportunity to align a wide range of media servers with varying capacities and features from small, micro voice processes to large video media servers. For all of these boxes one thing can be certain if they are mediactrl compliant - they WILL have an implementation of the control framework. 
well I am not worried about the media servers that support the
mediactrl framework but those which don't and which will be the
majority for some time. It is possible to build a service platform
today that consists of application servers and media servers with both
not supporting mediactrl. Limiting the MRB to support mediactrl would
mean that the really useful concept of MRB can not be deployed. I admit
that  designing an environment in which all components  are based on
the same framework, namely the mediactrl framework,  is very good.
However, in an environment that is fast moving supporting simpler and
yet more established mechanisms would be of great practical value.

cheers

Chris.


Dorgham

Chris Boulton wrote:

All,
As you may have noticed, I have posted a new version of the Media Resource Brokering draft to the archives (http://www.ietf.org/id/draft-ietf-mediactrl-mrb-01.txt). This version of the document represents a substantial leap forward after all the hard work and input from the group over the last couple of months. The main updates are:
- The inclusion of the In-line text that the group worked before Stockholm. 
- The first draft of the MRB Publish interface.
The text for the Publish interface and its associated schema are still immature but provide a good representation of the output from the design team. It would be beneficial for the interface to be reviewed and discussed over the coming weeks so that we can refine before the next IETF meeting. I will be releasing another version of the document before Hiroshima which will:
- progress the interface schema and its associated text based on group feedback. 
- include a first draft of the Consumer interface.
- Address as many of the editors notes as possible on the list. Any remaining will then be topic for discussion at the meeting.
I would again like to thank everyone for the work so far and look forward to receiving your input. 

Chris and Lorenzo.







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