Re: [tcpm] 793bis: what to say about source routing

Hi, Michael,

Although *use* of source routing with TCP is optional, *support for* source routing is not.

Source routing is not deprecated for IPv4 and we should not imply support for it in TCP is optional in any way.

TCP isn’t deciding whether to use source routing, so this doc has no rationale for warning about whether source routing is enabled or not.

Joe

—
Joe Touch, temporal epistemologist
www.strayalpha.com

> On Dec 3, 2021, at 2:51 AM, Scharf, Michael <Michael.Scharf@hs-esslingen.de> wrote:
> 
> Hi all,
>  
> The existing 793bis test already implies that use of source routing is optional, since it starts with an if-clause.
>  
> For what it is worth, I think that we could add a comment along the lines of „source routing may be disabled or unsupported on some systems“ to make this more explicit. I don’t see much harm in such an informative statement. If we go down this route, IMHO the 793bis spec does not have to discuss why stacks implement or don’t implement features below TCP.
>  
> Having said this, I don’t see a strong need for any additional wording. I just don’t object to a brief note.
>  
> In any case, as long as there is no other PS or BCP guidance, the normative statements in 793bis should not change 1122.
> Michael (with no hat whatsoever) 
>  
>  
> From: tcpm <tcpm-bounces@ietf.org <mailto:tcpm-bounces@ietf.org>> On Behalf Of touch@strayalpha.com <mailto:touch@strayalpha.com>
> Sent: Wednesday, December 1, 2021 5:44 AM
> To: Gorry Fairhurst <gorry@erg.abdn.ac.uk <mailto:gorry@erg.abdn.ac.uk>>
> Cc: tcpm IETF list <tcpm@ietf.org <mailto:tcpm@ietf.org>>
> Subject: Re: [tcpm] 793bis: what to say about source routing
>  
> Hi, Gorry, 
>  
> To me, your final point is the most significant. 
>  
> Notably, putting the proposed note in TCP would suggest either that IP source routing is deprecated (it isn’t) or that TCP support for it should be considered optional (it should not) - regardless of whether is deprecated in the future or not.
>  
> Joe
>  
> —
> Joe Touch, temporal epistemologist
> www.strayalpha.com <http://www.strayalpha.com/>
> 
> 
> On Nov 30, 2021, at 1:17 AM, Gorry Fairhurst <gorry@erg.abdn.ac.uk <mailto:gorry@erg.abdn.ac.uk>> wrote:
>  
> To me the security concerns are not relevant here - this is a transport spec., and the mechanisms below need to be designed correctly, and while an exmaple or two are good, it seems rather silly to state or enumerate the different sub-transport protocols or their individual concerns.
>  
>  
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