[Simple] MSRP URLs

[Miguel Garcia <Miguel.An.Garcia at nokia.com>]

Hi:

A few comments about section 5 of the MSRP draft:

http://www.ietf.org/internet-drafts/draft-ietf-simple-message-sessions-08.txt

1) The draft should describe the type of resources that are identified 
by an MSRP URL. So I would suggest to add an introductory paragraph at 
the beginning of section 5 that says something on the following lines:

   The MSRP and MSRPS URL schemes are used to designate a session of
   instant messages at a particular host computer.

  Question: is this definition also applicable to relays?

2) RFC 2396 is under revision, nowadays 
draft-fielding-uri-rfc2396bis-06.txt. I am not sure if you still want to 
refer to RFC 2396 or the revision of it. I guess this depends of which 
draft makes it first to the IESG.

Among other things, in case you want to refer to rfc2396bis, this draft 
has removed the definition of "hostport". Now it is just "host [: port]"

3) The current definition of an MSRP URL includes a "resource" part, 
when actually it is a "path" or "session-id", because a "resource" is 
the the whole MSRP URL, including the URI scheme and the hostname.

So I would suggest to replace the current definition:

    MSRP_urls = msrp-scheme "://" [userinfo "@"] hostport ["/"
      resource] ";" transport
      resource = 1*unreserved

with this other one:

    MSRP_urls = msrp-scheme "://" [userinfo "@"] hostport ["/"
      path] ";" transport
      resource = 1*unreserved

4) According to rfc2396bis, "unrerved" is defined as:

unreserved    = ALPHA / DIGIT / "-" / "." / "_" / "~"

On purpose "unreserved" does not include "sub-delims", which is defined as:

    sub-delims    = "!" / "$" / "&" / "'" / "(" / ")"
                  / "*" / "+" / "," / ";" / "="

I guess it is OK for MSRP that the path is formed of unreserved 
characters, not including sub-delims. But I would like to point this out 
in case someone feels the path needs to include sub-delims.

5) I find a contradiction that we, on one hand, allow to have a 
"userinfo" part in the MSRP URL including a reference to RFC 2396, and 
on the other hand we restrict the "userinfo" definition in RFC 23964 to 
unreserved characters.

RFC 2396 (and 2396bis) allow to have escaped characters in the userinfo. 
However, MSRP does not, but still refers to 2396 for the definition of 
userinfo.

So, if the "userinfo" defined in the MSRP URL is different from (or a 
subset of) the "userinfo" defined in RFC 2396, then I would suggest to 
change the name (perhaps "unescaped-userinfo"), and avoid the reference 
to RFC 2396.

6) Section 5.1 reads on the second bullet point:

   2.  If the hostpart contains an eplicit IP address, and/or port,
       these are compared numerically.  Otherwise, hostpart is compared
       as a case insensitive character string.

I was wondering in the how to treat zeros in either IPv4 or IPv6 (IPv6 
uses this quite oftenly). The missleading word is "numerically", since I 
am not sure if the "::" should be normalized by adding trailing and 
leading zeros or not.

Is it the intention that the following two URLs are equivalent and MSRP 
endpoints should detect it?

   msrp://[1080:0:0:0:8:800:200C:417A]/aodisfa;tcp
   msrp://[1080::8:800:200C:417A]/aodisfa;tcp

A clarification should be written.


Regards,

        Miguel


--
Miguel A. Garcia           tel:+358-50-4804586
Nokia Research Center      Helsinki, Finland

_______________________________________________
Simple mailing list
Simple at ietf.org
https://www1.ietf.org/mailman/listinfo/simple