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

[Alexey Melnikov <[e-mail]>]

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>