Re: [ppsp] Call for WG consensus on Tracker Protocol encoding

Hi Folks,

The current version of the Base Tracker Protocol draft had followed all previous recommendations of the WG, and, as you may recall, the initial specifications described a text-based encoding (HTTP/XML) that could even be represented in binary form on the wire.

Later, it was recommended in the WG to "specify the protocol" not using a specific encoding method as it would seem as mandatory, and that was done using a syntax and format for the Protocol messages defined with a C-like syntax, similar to the presentation language used to defined TLS, just to “document” the protocol. Consequently, the encoding “examples" (HTTP/XML) for the protocol were removed from the document, remaining only in part 4 of the draft the mention:

“PPSP-TP is a message-oriented request/response protocol.  The messages can be encoded using binary type or text type, which can be indicated in the Content-Type field in HTTP/1.1 [RFC2616], but that definition is not in the scope of this specification.” 

I personally welcome the chance given by the WG to have a mandatory encoding specification for the protocol, and I am convinced that it would be just a question of getting the consensus on using one of the following:

1. HTTP/XML: just pure text but also directly representable in binary format on the wire (in "real-time") using current well known methods and standards.
2. HTTP/JSON: just pure text but also directly representable in binary format on the wire (in "real-time”) using current well known methods and standards.

None of those require special work from what was described and exemplified in earlier versions of the draft (HTTP/XML), just a simple transcription of previous text to the current document, or a transcription of the previous text but with a conversion of the messages body to JSON (XML to JSON is straightforward).

As other co-authors also mentioned, a pure binary format, although apparently more “efficient” on the wire, would bring unnecessary complexity to the implementation, usage and extensibility.

Thanks. 

Regards,

Dr. Rui Santos Cruz, Ph.D.
rui.cruz@ieee.org

IST/INESC-ID/INOV - Lisbon, Portugal
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> On 13 Nov 2014, at 02:27, Zongning <zongning@huawei.com> wrote:
> 
> Hi, all,
>  
> Firstly, thanks to the co-authors of Base Tracker Protocol for persistently moving the draft forward.
>  
> Now the outstanding issue is that as a Standard Track document, we really NEED to agree on a mandatory encoding for the interoperable on-the-wire Tracker Protocol. As discussed in the PPSP session today, we will start WGLC for the draft, provided that we can reach a rough consensus on the encoding option and the co-authors revise the draft accordingly.
>  
> Currently we have two options mentioned in the draft – they are text based and binary based. For an exemplary comparison, please see Section 3.1 in the draft. Could folks in the group give their opinions on which encoding option is preferred for Tracker Protocol, and why? People are welcome to give other options beyond text and binary, but please do show us the reason for choosing them.
>  
> The during of this call will not last too long, before the co-chairs will make a decision. So, please do contribute your technical expertise in this perspective, to enlight the group.
>  
> Thanks.
>  
> -Yunfei & Ning
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