Re: [tcpm] draft-ietf-tcpm-urgent-data-06

[Ronald Bonica <[e-mail]>]

Alfred,

I am not sure that we want TCP stack implementers to "repair" this feature. That is may make some applications that rely on broken stack behaviors stop working.

If anything, stack implementers should remove this feature from the stack on the sending side.

                                                       Ron

> -----Original Message-----
> From: [e-mail] [mailto:[e-mail]]
> Sent: Thursday, September 30, 2010 11:49 AM
> To: Ronald Bonica; [e-mail]
> Cc: [e-mail]
> Subject: Re: [tcpm] draft-ietf-tcpm-urgent-data-06
> 
> At Mon, 27 Sep 2010 15:49:05 -0400, Ronald Bonica wrote:
> 
> > I think that you have hit the nail on the head.  Reading through
> > Sections 1-5, I thought that we were trying to fix the feature.
> > Only in Section 6 did I realize that we really wanted to drive
> > a stake through its heart.
> >
> > Maybe if we changed the title and added some test to the abstract and
> > introduction, this would be better.  Otherwise, people may spend time
> > and money fixing the TCP Urgent option instead of just avoiding it.
> 
> Oh!  Pay attention!
> TCP implementers usually are very different folks than application
> designers & implementers!
> 
> So giving advice to the former group to sanitize their kernel
> stacks (as far as necessary, and based on a uniform, consistent
> interpretation of the old contradictory specs) is one point,
> and entirely different from giving advice to the apps folks
> to avoid the feature.
> 
> IMHO, we need both -- fixing the kernel (to the benfit of
> existing apps), and avoiding usage of the feature in new apps.
> 
> 
> Footnote -- as pointed out on-list during the infancy of the draft:
>   The Telnet protocol is tolerant regarding the two interpretations
>   of the Urgent Pointer because the trailing DM control character of
>   the Telnet SYNC sequence (that's the octet to which the UP points)
>   is effectively ignored by the receiving peer in parsing the input
>   it reads from the socket (cf. RFC 1123, Section 3.2.4).
> 
> 
> Kind regards,
>   Alfred HÎnes.
> 
> --
> 
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