CLUE design team meeting CLUE protocol CLUE design team meeting 29/05/2014

Outline Message structures Versioning and options Discussion about CLUE protocol updates reflecting changes in draft-ietf-clue-signaling draft-ietf-clue-data-channel 29/05/2014

A common basis 29/05/2014

A common basis Each CLUE message extends the basic CLUE message type Common info: protocol: CLUE v: version clueId: the sender’s id within the telepresence system sequenceNr 29/05/2014

Call flow example X Y OPT, sn: Xopt OPT_RES, sn: Yopt OPT_ACK, sn: Xopt+1 ADV, sn: Xmp ADV_ACK, sn: Ymc CONF, sn: Ymc +1 CONF_RES, sn: Xmp+1 X CI Y CR ADV, sn: Ymp X MP Y MC CONF+ACK, sn: Xmc X MC Y MP CONF_RES, sn: Ymp+1 29/05/2014

Sequence numbers Each CLUE endpoint manages 3 local sequence number (SN): 1 for the OPTIONS mechanism (before starting the MP and MC state machines) (Xopt, Yopt) 1 for the MP state machine (Xmp, Ymp) 1 for the MC state machine (Xmc, Ymc) SN are randomly generated and incremented of 1 each time a new message is sent SN can be used to make reference to the corresponding message within a CLUE dialogue (between a MP and a MC) 29/05/2014

Advertisement The configure request can refer to the sequence number of the advertisement. 29/05/2014

Advertisement ACK 29/05/2014

Configure 29/05/2014

Configure Response 29/05/2014

READV A refresh mechanism to retrieve the MP’s current capabilities lastReceivedAdv: the version number of the last correctly received Adv 0, if no ADV has been delivered yet If an ADV is malformed, a NACK comes back to the MP 29/05/2014

READV Response The following CONF will use the READV Response sequence number in place of the ADV sequence number Diff mechanism to be discussed (introduction of a choice section) 29/05/2014

Versioning Imported from the signaling doc: A version has major and minor components, each a non-negative integer. Major version changes denote non-interoperable changes Minor version changes denote schema changes that are backward compatible by ignoring unknown XML elements, or other backward compatible changes. If a common major version cannot be negotiated, then CLUE MUST NOT be used. From Paul’s doc: -Minor versions are always backwards compatible, so support for a minor version implies support for all smaller minor versions 29/05/2014

Options mechanism The Channel Initiator issues the OPTIONS message with A boolean flag telling if it is able to act as a MP <mediaProvider> A boolean flag telling if it is able to act as a MC <mediaConsumer> All the supported versions All the supported options 29/05/2014

OPTIONS 29/05/2014

Options mechanism (2 ways) Current solution: 2 ways The Channel Reveiver issues an OPTIONS response carrying A response code telling if an agreement has been found or not A reason string explaining the response code <mediaProvider> <mediaConsumer> The highest commonly supported version The common options If a common version can be found, the MP/MC state machines start For example, if both parts are able to act only as media providers with each other, the CLUE session should be terminated. Response code and response string signal the error 29/05/2014

OPTIONS Response (2ways) 29/05/2014

Options mechanism (3 ways) Proposal: 3 ways The Channel Reveiver issues an OPTIONS Response carrying <mediaProvider> <mediaConsumer> All the supported versions All the supported options 29/05/2014

OPTIONS Response (3ways) 29/05/2014

Options mechanism (3 ways) Proposal: 3 ways The Channel Initiatior send an OPTIONS ACK carrying A response code telling if the elaboration of the options message is ok or not A reason string explaining the response code The highest commonly supported version The common options If a common version can be found, the MP/MC state machines start If we put all the supported things of the CR in the OPTIONS RESPONSE, the OPTIONS ACK would carry the final agreement 29/05/2014

OPTIONS ACK (3ways) 29/05/2014

Comparison 2 ways: 3 ways: the Channel Initiator will not know all the supported versions and options of the Channel Receiver, but only the common ones The matching is up to the Channel Receiver 3 ways: Both parties know all the capabilities of each other The matching is up to the Channel Initiator One message more 29/05/2014

Some notes There is a need for communication between the CLUE stata machine and the SDP negotiation engine Example: a CLUE endpoint cannot issue a CONF before the SDP info arrives State machines need to be updated considering the dependancy between CLUE and SDP There is no (total) independence 29/05/2014