Hi Chrisjust went through the draft and it surely is a substantial step forward. There are a couple of issues though that I would like to discuss related to the Publisher Interface Exchange Protocol.
The draft suggests using the mediactrl framework as the basis for the communication between the MRB and the media servers. Would be good if the draft included some discussion on the advantages of this. 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) - 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. - 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 - 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. Using the mediactrl framework as the interface between the MRB and the MS means however that this concept can only be used if all the MS support the mediactrl framework. While this should be the final goal, there are already a lot of scenarios today in which a separation between the application logic and media processing is possible. Unfortunately the mediactrl framework is not supported there.
The goal of using the mediactrl framework is to enable the media servers to publish their capabilities and to enable the MRB to monitor the current status of the media servers. There are already other SIP based mechanisms for achieving this -please check http://tools.ietf.org/search/draft-sisalem-mediactrl-mrbctrl-00 for a proposal of such mechanisms. Using these mechanisms would allow to implement the MRB as a SIP proxy (or a transparent SIP proxy even) that can be deployed in todays networks without having to wait for mediactrl based media servers.
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.