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Re: [Sip] draft-ietf-sip-record-route-fix-08 Changes



OK for me too. 

John

> -----Original Message-----
> From: Robert Sparks [mailto:rjsparks at nostrum.com] 
> Sent: 12 August 2009 21:15
> To: Dean Willis
> Cc: Elwell, John; sip at ietf.org; BONNAERENS Ben
> Subject: Re: [Sip] draft-ietf-sip-record-route-fix-08 Changes
> 
> I skipped straight to the end (will come back and read how you got  
> there later).
> But yes, I think the rewrite you have at the end says the the same  
> thing.
> 
> RjS
> On Aug 12, 2009, at 2:42 PM, Dean Willis wrote:
> 
> >
> > On Aug 11, 2009, at 8:35 PM, Robert Sparks wrote:
> >
> >> John -
> >>
> >> Would this substitution address your concern?
> >>
> >>    When TLS is used on the transport on either side of the proxy  
> >> the URI
> >>    chosen to place in the Record-Route header field value  
> >> reflecting the
> >>    interface using TLS will need to use a sips: URI or 
> ensure that  
> >> a sip:
> >>    URI resolves (per the procedures of [RFC3263]) to using 
> TLS rather
> >>    than attempting to use the deprecated  "transport=tls" URI  
> >> parameter.
> >>    See [RFC3261] Section 26.2.2 and [I-D.ietf-sip-sips] 
> Section 3.1.4
> >>    for more discussion
> >>
> >
> >
> > That makes my head hurt!
> >
> > Compound sentences should make sense even with clauses redacted.
> >
> > Let's play some games with this mind twister:
> >
> >
> > First I'll try to scope the sub-clauses:
> >
> >> (When TLS is used (on the transport (on either side of the 
> proxy)))  
> >> the URI (chosen to place (in the Record-Route header field value  
> >> (reflecting the interface using TLS))) will need to use a 
> sips: URI  
> >> or ensure that a sip: URI resolves (per the procedures of  
> >> [RFC3263]) to using TLS (rather than attempting to use the  
> >> deprecated  "transport=tls" URI parameter).
> >>
> >
> > One reduction to see if it makes sense:
> >
> >> When TLS is used the URI chosen to place in the 
> Record-Route header  
> >> field value will need to use a sips: URI or ensure that a 
> sip: URI  
> >> resolves (per the procedures of [RFC3263]) to using TLS 
> rather than  
> >> attempting to use the deprecated  "transport=tls" URI parameter.
> >
> >
> > Let's pull some smaller pieces out of this:
> >
> >> When TLS is used the URI chosen to place in the 
> Record-Route header  
> >> field value will need to use a sips: URI.
> >
> >
> > "chosen to place" is clumsy. Let's substitute "placed", add 
> a comma  
> > for the subordination,  and see if it gets better.
> >
> >> When TLS is used, the URI placed in the Record-Route header field  
> >> value will need to use a sips: URI.
> >
> > What does it mean for a URI to use a URI? I think perhaps it needs  
> > to BE a SIPS URI.
> >
> > Rewritten:
> >
> >> When TLS is used, the URI placed in the Record-Route header field  
> >> value will need to be a sips: URI.
> >
> > Now lets look at the other half of that clause:
> >
> >> When TLS is used, the URI placed in the Record-Route header field  
> >> value will need to ensure that a sip: URI resolves (per the  
> >> procedures of [RFC3263]) to using TLS rather than 
> attempting to use  
> >> the deprecated  "transport=tls" URI parameter.
> >
> >
> > How does a URI ensure that a ensure something about a URI?
> >
> > Maybe you mean:
> >
> >> When TLS is used, the URI placed in the Record-Route header field  
> >> value MUST resolve (per the procedures of [RFC3263]) to using TLS  
> >> rather than attempting to use the deprecated  "transport=tls" URI  
> >> parameter.
> >
> >
> > I'm still stumbling over "resolve to using TLS rather than  
> > attempting to use the deprecated  "transport=tls" URI 
> parameter." So  
> > let's just lop off the sentence from "rather than . . ." and move  
> > that out.
> >
> > What's wrong with
> >
> >> When TLS is used, the URI placed in the Record-Route header field  
> >> value MUST resolve (per the procedures of [RFC3263]) to using TLS .
> >
> > Is "resolve to using TLS" the same thing as "resolve using TLS"? I  
> > think they're subtly different, but the complexity still 
> scares me.  
> > I think we're trying to say that the application of RFC 3263  
> > procedures to the URI must result in a next-hop that is reachable  
> > only by TLS.
> >
> > So let's try a rewrite based on these assumptions. How about this:
> >
> >> When TLS is used, the URI placed in the Record-Route header field  
> >> MUST encode a next-hop that will be reached using TLS. There are  
> >> two ways for this to work. The first way is for the URI placed in  
> >> the Record-Route to be a sips: URI. The second is for the URI  
> >> placed in the Record-Route to be constructed such that 
> application  
> >> of  RFC 3263 resolution procedures
> >> to that URI produces a result reachable only using TLS. Proxies  
> >> compliant with this specification MUST NOT use a "transport=tls"  
> >> parameter on the URI placed in the Record-Route because the  
> >> "transport=tls" usage was deprecated by RFC 3261.
> >
> > Does that mean the same thing to you as the original 
> megasentence did?
> >
> > --
> > Dean
> >
> >
> >
> 
>