Re: [stir] Making STIR SIP messages smaller

[Keith Drage <[e-mail]>]

I have memories of SIP message length being discussed way back in days 
of the SIP working group, i.e. pre SIPCORE, precisely in regard to the 
UDP versus TCP question. And all the issues relating to using TCP were 
raised at that time.

The answer at that time was essentially that when message lengths get 
long, TCP is the way to go, and that TCP is mandatory to implement in 
any case. No mileage was seen to be gained to making SIP more "UDP 
friendly".

Talking to some of my own implementors at the time, some of the problems 
identified with TCP were seen by them as just being poor software 
design, rather than inherent problems.

One point I would make is that if this is a problem, then STIR is the 
cause of the problem, rather than the body that needs to solve the 
problem. SIPCORE should be brought into the discussion.

Keith

Co-chair of the SIP WG at the time

>    “For reliable transports, the response is normally sent on the
>
>    connection on which the request was received.  Therefore, the client
>
>    transport MUST be prepared to receive the response on the same
>
>    connection used to send the request.”
>
> I KNOW that there exist interoperability issues with TCP. But, if 
> people implement TCP support wrong e.g., because they misunderstand 
> the spec, shouldn’t we then instead clarify the spec?
>
> Regards,
>
> Christer
>
> On Tue, Apr 13, 2021 at 4:14 PM Chris Wendt <[e-mail] 
> <mailto:[e-mail]>> wrote:
>
>     Would be good to understand better why, i have not heard that
>     feedback from the STIR/SHAKEN community lately or maybe folks have
>     given up complaining :)  While there was much talk about it maybe
>     2-3 years ago, those conversations have been pretty quiet as of
>     late. As far as i’m aware much of the equipment both commercial
>     and open source and deployments have adapted and adjusted, but
>     maybe there is parts of the eco-system that haven’t gotten there yet.
>
>     -Chris
>
>
>
>         On Apr 13, 2021, at 1:54 PM, Roman Shpount <[e-mail]
>         <mailto:[e-mail]>> wrote:
>
>         Unfortunately, the message increase caused by the Identity
>         header causes a call failure rate increase of at least a few
>         percent. There is a substantial number of deployments affected
>         by this and unlike things like History-Info, this feature is
>         now required by law.
>
>         _____________
>         Roman Shpount
>
>         On Tue, Apr 13, 2021 at 1:50 PM Mary Barnes
>         <[e-mail]
>         <mailto:[e-mail]>> wrote:
>
>             Yeah - like nearly 20 years ago when we added headers like
>             History-Info.   And, really if you want to use a text
>             based protocol, you surely can't have small message sizes
>             as a design priority.
>
>             On Tue, Apr 13, 2021 at 4:40 AM Christer Holmberg
>             <christer.holmberg=[e-mail]
>             <mailto:[e-mail]>> wrote:
>
>                 >I agree that we need to figure out a way to make Identity
>                 headers smaller. As it stands right now, the Identity
>                 header with "shaken" PASSporT type adds around 600
>                 bytes to an INVITE message.
>
>                 >This makes typical SIP INVITE messages go from around 1K in size
>                 to 1.6K, which is bigger than the UDP MTU.
>
>                 With or without Identity, didn’t that ship sail a long
>                 time ago? :)
>
>                 Regards,
>
>                 Christer
>
>                 On Mon, Apr 12, 2021 at 5:39 PM Alec Fenichel
>                 <[e-mail]
>                 <mailto:[e-mail]>> wrote:
>
>                     I guess what I am trying to say is that I think we
>                     should remove ppt from the examples because as you
>                     say, people tend to code to examples and smaller
>                     Identity headers would be ideal.
>
>                     I don’t mean to hijack this thread, but I have
>                     been meaning to bring this up anyways and it is
>                     related. Is there a reason I’m just overlooking
>                     for requiring the “info” parameter when a
>                     full-form PASSporT is used? If not, can we make it
>                     optional? The reason I ask is that with OOB, the
>                     transit provider receives a PASSporT out-of-band
>                     and then needs to construct an Identity header.
>                     Because of the “info” parameter requirement, the
>                     transit provider must decode the PASSporT in order
>                     to determine the “info” parameter. This is the
>                     only reason that a transit provider needs to
>                     decode the PASSporT. This isn’t difficult so it
>                     doesn’t really matter, but I figured I’d ask about
>                     potentially making the “info” parameter optional.
>                     Also, it makes the Identity header smaller which
>                     is always a good thing.
>
>                     Sincerely,
>
>                     Alec Fenichel
>
>                     Senior Software Architect
>
>                     [e-mail]
>                     <mailto:[e-mail]>
>
>                     [phone]
>
>                     TransNexus
>
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