Re: [stir] Making STIR SIP messages smaller

[Alec Fenichel <[e-mail]>]

My motivations from making the “info” parameter optional aren’t really about the SIP message size. When using OOB, the transit provider receives one or more PASSporTs (not Identity headers, but PASSporTs) and needs to construct one or more Identity headers. If the “info” parameter was optional, then the transit provider wouldn’t need to decode the PASSporT to extract the “x5u” to set the “info” parameter. The transit provider would also not set the “alg” and “ppt” parameters either. So,

 

1. Can we make the “info” parameter option?
2. Can we not include the “info”, “alg”, and “ppt” parameters in examples that show full form PASSporTs because as previously mentioned, implementors often code to the examples and the STI-VS should be implemented to support not receiving these parameters?

 

Sincerely,

 

Alec Fenichel

Senior Software Architect

[e-mail]

[phone]

TransNexus

 

From: Christer Holmberg <[e-mail]>
Date: Tuesday, April 13, 2021 at 16:27
To: Chris Wendt <[e-mail]>, Roman Shpount <[e-mail]>
Cc: Mary Barnes <[e-mail]>, Alec Fenichel <[e-mail]>, Marc Petit-Huguenin <[e-mail]>, [e-mail] Mail List <[e-mail]>
Subject: RE: [stir] Making STIR SIP messages smaller

Hi,

 

SIP implementations need to support TCP, and they need to support long messages. If we wanted to make SIP more compact, there are tons of things we could do.

 

And, if an implementations makes it or breaks it based on presence of the info parameter, that implementation is walking on very thin ice…

 

Regards,

 

Christer

 

From: Chris Wendt <[e-mail]>
Sent: tiistai 13. huhtikuuta 2021 23.14
To: Roman Shpount <[e-mail]>
Cc: Mary Barnes <[e-mail]>; Christer Holmberg <[e-mail]>; Alec Fenichel <[e-mail]>; Marc Petit-Huguenin <[e-mail]>; [e-mail] Mail List <[e-mail]>
Subject: Re: [stir] Making STIR SIP messages smaller

 

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]> 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]> 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]> 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]> 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]

[phone]

TransNexus

 

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