Re: [bfcpbis] Alexey Melnikov's Discuss on draft-ietf-bfcpbis-sdp-ws-uri-08: (with DISCUSS and COMMENT)

["Ram Mohan R (rmohanr)" <[e-mail]>]

Thanks Alexey,
I will publish the revision after fixing the nits you pointed below

Ram

-----Original Message-----
From: Alexey Melnikov <[e-mail]>
Date: Saturday, 4 February 2017 at 10:51 PM
To: "Ram Mohan R (rmohanr)" <[e-mail]>
Cc: Alissa Cooper <[e-mail]>, Ben Campbell <[e-mail]>, The IESG <[e-mail]>, "[e-mail]" <[e-mail]>, "[e-mail]" <[e-mail]>, "Charles Eckel (eckelcu)" <[e-mail]>, "[e-mail]" <[e-mail]>
Subject: Re: [bfcpbis] Alexey Melnikov's Discuss on draft-ietf-bfcpbis-sdp-ws-uri-08: (with DISCUSS and COMMENT)

    Hi Ram,
    
    > On 30 Jan 2017, at 05:30, Ram Mohan R (rmohanr) <[e-mail]> wrote:
    > 
    > Hi Alexey/all,
    > 
    > Please find the diffs with the changes to use single attribute. This diff also has other comments from Ben, Kathleen incorporated.
    
    This looks much better, thank you!
    
    You have introduced a typo in one place (search for "wwebsocket").
    
    Best Regards,
    Alexey
    
    > Regards,
    > Ram
    > 
    > -----Original Message-----
    > From: "Ram Mohan R (rmohanr)" <[e-mail]>
    > Date: Thursday, 19 January 2017 at 9:30 AM
    > To: Alissa Cooper <[e-mail]>
    > Cc: Alexey Melnikov <[e-mail]>, The IESG <[e-mail]>, "[e-mail]" <[e-mail]>, "[e-mail]" <[e-mail]>, "Charles Eckel (eckelcu)" <[e-mail]>, "[e-mail]" <[e-mail]>
    > Subject: Re: [bfcpbis] Alexey Melnikov's Discuss on draft-ietf-bfcpbis-sdp-ws-uri-08: (with DISCUSS and COMMENT)
    > 
    >    Hi Alissa,
    > 
    >    I don’t have a strong opinion on this. Either way (having a single attribute or two different SDP attributes) would work.
    > 
    >    Implementations can still retrieve the value (URI) of that attribute and based on the proto line (TCP/WS/BFCP or TCP/WSS/BFCP) match the URI against ws or wss schema defined in RFC6455.  I would expect such a validation to happen across layers.
    >    The SDP stack parser to look at the proto line transport value (TCP/WS/BFCP or TCP/WSS/BFCP) and check for presence of a=websocket-uri attribute. The value of this attribute (ws or wss schema) can be passed *as is* to the application (in this case BFCP client application) which will validate it against the schema in RFC 6455.
    > 
    >    I am OK to incorporate this comment to have a single SDP attribute. 
    > 
    >    Regards,
    >    Ram
    > 
    >    -----Original Message-----
    >    From: Alissa Cooper <[e-mail]>
    >    Date: Thursday, 19 January 2017 at 1:58 AM
    >    To: "Ram Mohan R (rmohanr)" <[e-mail]>
    >    Cc: Alexey Melnikov <[e-mail]>, The IESG <[e-mail]>, "[e-mail]" <[e-mail]>, "[e-mail]" <[e-mail]>, "Charles Eckel (eckelcu)" <[e-mail]>, "[e-mail]" <[e-mail]>
    >    Subject: Re: [bfcpbis] Alexey Melnikov's Discuss on draft-ietf-bfcpbis-sdp-ws-uri-08: (with DISCUSS and COMMENT)
    >    Resent-From: <[e-mail]>
    >    Resent-To: <[e-mail]>, <[e-mail]>
    >    Resent-Date: Thursday, 19 January 2017 at 1:58 AM
    > 
    >        Hi Ram,
    > 
    >        I had some further conversation with Alexey on the side and wanted to come back to a question he posed: is there a reason why a=ws-uri and a=wss-uri both need to be specified? Why can’t a single label be specified, say a=websocket-uri, and then have normative language requiring the scheme in the URI itself to match what’s in the associated m-line (ws:// for TCP/WS/BFCP and wss:// for TCP/WSS/BFCP)? Won’t it be more efficient for implementations to grab the URI itself anyway and check that the scheme matches the m-line?
    > 
    >        Thanks,
    >        Alissa
    > 
    >> On Jan 17, 2017, at 9:40 AM, Ram Mohan R (rmohanr) <[e-mail]> wrote:
    >> 
    >> Alissa,
    >> 
    >> I am fine with the proposed text.
    >> 
    >> Thanks,
    >> Ram
    >> 
    >> -----Original Message-----
    >> From: Alissa Cooper <[e-mail]>
    >> Date: Tuesday, 17 January 2017 at 8:07 PM
    >> To: Alexey Melnikov <[e-mail]>
    >> Cc: The IESG <[e-mail]>, "[e-mail]" <[e-mail]>, "[e-mail]" <[e-mail]>, "Charles Eckel (eckelcu)" <[e-mail]>, "[e-mail]" <[e-mail]>, "Ram Mohan R (rmohanr)" <[e-mail]>
    >> Subject: Re: [bfcpbis] Alexey Melnikov's Discuss on draft-ietf-bfcpbis-sdp-ws-uri-08: (with DISCUSS and COMMENT)
    >> 
    >>   Alexey, would the following changes clarify things?
    >> 
    >>   Section 4.1
    >>   OLD
    >>   the server side, which could be either
    >>      the offerer or answerer, MUST add an "a=ws-uri" or "a=wss-uri"
    >>      attribute in the media section
    >>   NEW
    >>   the server side, which could be either
    >>      the offerer or answerer, MUST add an "a=ws-uri" or "a=wss-uri”
    >>      attribute (but not both) in the media section
    >> 
    >>   Section 4.3
    >>   OLD
    >>   If the answers assigns SDP "setup" attribute with "passive", then it
    >>      MUST have a URI in either "a=ws-uri" or "a=wss-uri" attribute
    >>      depending on whether the application uses WebSocket or
    >>      secureWebSocket.
    >>   NEW
    >>   If the answers assigns SDP "setup" attribute with "passive", then it
    >>      MUST have a URI in either "a=ws-uri" or "a=wss-uri" attribute
    >>      (but not both) in the media section, depending on whether the application uses WebSocket or
    >>      secureWebSocket.
    >> 
    >>   Ram, would you be okay with those clarifications?
    >> 
    >>   Alissa
    >> 
    >> 
    >>> On Jan 16, 2017, at 10:09 AM, Ram Mohan R (rmohanr) <[e-mail]> wrote:
    >>> 
    >>> Hi Alexey,
    >>> 
    >>> -----Original Message-----
    >>> From: Alexey Melnikov <[e-mail]>
    >>> Date: Monday, 16 January 2017 at 8:25 PM
    >>> To: "Ram Mohan R (rmohanr)" <[e-mail]>, The IESG <[e-mail]>
    >>> Cc: "[e-mail]" <[e-mail]>, "[e-mail]" <[e-mail]>, "Charles Eckel (eckelcu)" <[e-mail]>, "[e-mail]" <[e-mail]>
    >>> Subject: Re: [bfcpbis] Alexey Melnikov's Discuss on draft-ietf-bfcpbis-sdp-ws-uri-08: (with DISCUSS and COMMENT)
    >>> 
    >>>  Hi Ram,
    >>> 
    >>>>  On Mon, Jan 16, 2017, at 02:49 PM, Ram Mohan R (rmohanr) wrote:
    >>>> Hi Alexey,
    >>>> 
    >>>> Please see inline <Ram>
    >>>> 
    >>>> -----Original Message-----
    >>>> From: Alexey Melnikov <[e-mail]>
    >>>> Date: Monday, 16 January 2017 at 7:57 PM
    >>>> To: "Ram Mohan R (rmohanr)" <[e-mail]>, The IESG <[e-mail]>
    >>>> Cc: "[e-mail]"
    >>>> <[e-mail]>, "[e-mail]"
    >>>> <[e-mail]>, "Charles Eckel (eckelcu)" <[e-mail]>,
    >>>> "[e-mail]" <[e-mail]>
    >>>> Subject: Re: [bfcpbis] Alexey Melnikov's Discuss on
    >>>> draft-ietf-bfcpbis-sdp-ws-uri-08: (with DISCUSS and COMMENT)
    >>>> 
    >>>>  Hi Ram,
    >>>> 
    >>>>>  On Mon, Jan 16, 2017, at 06:09 AM, Ram Mohan R (rmohanr) wrote:
    >>>>> Hi Alexey,
    >>>>> 
    >>>>> Thanks for your feedback. Please see inline <Ram>
    >>>>> 
    >>>>> -----Original Message-----
    >>>>> From: bfcpbis <[e-mail]> on behalf of Alexey Melnikov
    >>>>> <[e-mail]>
    >>>>> Date: Saturday, 14 January 2017 at 3:49 AM
    >>>>> To: The IESG <[e-mail]>
    >>>>> Cc: "[e-mail]"
    >>>>> <[e-mail]>, "[e-mail]"
    >>>>> <[e-mail]>, "Charles Eckel (eckelcu)" <[e-mail]>,
    >>>>> "[e-mail]" <[e-mail]>
    >>>>> Subject: [bfcpbis] Alexey Melnikov's Discuss on
    >>>>> draft-ietf-bfcpbis-sdp-ws-uri-08: (with DISCUSS and COMMENT)
    >>>>> 
    >>>>>  Alexey Melnikov has entered the following ballot position for
    >>>>>  draft-ietf-bfcpbis-sdp-ws-uri-08: Discuss
    >>>>> 
    >>>> 
    >>>>>  ----------------------------------------------------------------------
    >>>>>  DISCUSS:
    >>>>>  ----------------------------------------------------------------------
    >>>>> 
    >>>>>  This is generally a well written document, but I have a small list of
    >>>>>  issues that I would like to discuss before recommending its approval:
    >>>>> 
    >>>>>  1) Are a=ws-uri and a=wss-uri mutually exclusive? (Section 4.3 is a
    >>>>>  good
    >>>>>  place to mention what to do if both are specified).
    >>>>> 
    >>>>> <Ram> Yes kind of. In a given media line (m= line) we will either have
    >>>>> a=ws-uri or a=wss-uri. That said a response from a BFCP server using
    >>>>> webSocket as a transport can
    >>>>> have two media lines one with ws and other with wss. Something like:
    >>>>> 
    >>>>> Answer (server):
    >>>>> m=application 50000 TCP/WSS/BFCP *
    >>>>> a=setup:passive
    >>>>> a=connection:new
    >>>>> a=wss-uri:wss://bfcp-ws.example.com?token=3170449312
    >>>>> m=application 50000 TCP/WS/BFCP *
    >>>>> a=setup:passive
    >>>>> a=connection:new
    >>>>> a=ws-uri:ws://bfcp-ws.example.com?token=3170449312
    >>>> 
    >>>>  [Alexey]: This is exactly my problem, you should specify how a
    >>>>  recipient
    >>>>  should handle your example above. If you only have 1 attribute, the
    >>>>  problem goes away entirely.
    >>>> 
    >>>> <Ram> in the above case, they are still two different m= lines. The
    >>>> receiver (after offer/answer is done) of this SDP connects to the URI
    >>>> mentioned in that m= line. 
    >>>> Note I just re-used the same URL/port in the example above. If there are
    >>>> multiple m=application media lines (they will be for different
    >>>> applications) being negotiated in SDP, one application may use secure WS
    >>>> and other application may use non-secure WS. The client after it receives
    >>>> the answer SDP will just setup the connection to the URI specified in the
    >>>> attribute.  
    >>> 
    >>>  Sorry, I was thinking about different example:
    >>> 
    >>>  m=application 50000 TCP/WSS/BFCP *
    >>>     a=setup:passive
    >>>     a=connection:new
    >>>     a=wss-uri:wss://bfcp-ws.example.com?token=3170449312
    >>>     a=ws-uri:ws://bfcp-ws.example.com?token=3170449312
    >>> 
    >>>  You have 2 conflicting URIs for the same m= line. Is this possible?
    >>> 
    >>> <Ram> No this is not possible. If the transport is TCP/WSS/BFCP we should have only a=wss-uri. If transport is TCP/WS/BFCP we should have only a=ws-uri.
    >>> 
    >>> Regards,
    >>> Ram
    >>> 
    >>>> I don’t see any problem in here.  
    >>>> 
    >>>> Regards,
    >>>> Ram
    >>>> 
    >>>>>  Why not a single attribute, considering that both ws: and wss: URIs
    >>>>>  are
    >>>>>  possible?
    >>>>> 
    >>>>> <Ram> I would still prefer two attributes. We just followed the
    >>>>> convention / approach that was used in [RFC6455].  
    >>>> 
    >>>> 
    >>> 
    >>> 
    >> 
    >> 
    >> 
    > 
    > 
    > 
    > 
    > 
    > <Diff_ draft-ietf-bfcpbis-sdp-ws-uri-08.txt - draft-ietf-bfcpbis-sdp-ws-uri-09.txt.html>
    > <draft-ietf-bfcpbis-sdp-ws-uri-09.txt>