Re: [Sipping] Last Call: draft-ietf-sipping-dialogusage (Multiple Dialog Usages in the Session Initiation Protocol) to Informational RFC

[Paul Kyzivat <[e-mail]>]

Ian,

Can you say more about what issues you see presented by B2BUAs when 
choosing between a multiple-usage dialog and several single-usage dialogs?

	Thanks,
	Paul

Ian Elz (CV/ETL) wrote:
>  
> I have noted the last call on this draft and the proposal to raise the
> draft to Informational RFC status.
> 
> While this draft gives a very detailed view of the issues relating to
> multiple dialog usage it also provides recommendations in areas where
> there is no or little examination of specific areas.
> 
> In section 5.7 Replacing Usages there is the statement:
> 
>      ...the interactions between Replaces and multiple dialog usages
>    have not been well explored.  More discussion of this topic is
>    needed.  Implementers should avoid this scenario completely.  
> 
> I do not believe that an informational RFC should include
> recommendations based upon little or no examination or lack of
> understanding of specific areas.
> 
> The draft as a whole recommends avoiding multiple dialog usage as it may
> be difficult to implement the required logic while only offering
> alternatives in simple network cases. With new ietf draft documents
> being published which highlight the impact on the network of B2BUA nodes
> I believe that there should be some examination of the impact of
> proposing that each new dialog usage be on a new dialog will have on
> networks which include B"B User Agents. 
> 
> If recommendations are made which influence vendors to only develop user
> agents which support single usage dialogs we may come to the situation
> where B2BUAs cannot be used in the network. This would prevent specific
> security measures such as identity hiding from untrusted networks as it
> would not be possible to map Contact headers. It would also prevent
> topology hiding. Preventing both of these measures could result increase
> the prevalence of denial of service and other attacks on the network.
> 
> While the proposals in this draft may prove to be a worthwhile addition
> to the knowledge of dialog and usage handling in the internet I believe
> that raising this draft to RFC status before the relevant studies have
> been undertaken in the associated areas, which are currently being
> studied, is premature.
> 
> Ian Elz
> 
> Office: + 44 24 764 35256
> gsm: [phone]
> [e-mail]
> 
> ------------------------------------------------------------------------
> -
> Message: 3
> Date: Thu, 26 Apr 2007 09:39:45 -0400
> From: The IESG <[e-mail]>
> Subject: [Sipping] Last Call: draft-ietf-sipping-dialogusage (Multiple
> 	Dialog  Usages in the Session Initiation Protocol) to
> Informational
> 	RFC 
> To: IETF-Announce <[e-mail]>
> Cc: [e-mail]
> Message-ID: <[e-mail]>
> 
> The IESG has received a request from the Session Initiation Proposal 
> Investigation WG (sipping) to consider the following document:
> 
> - 'Multiple Dialog Usages in the Session Initiation Protocol '
>    <draft-ietf-sipping-dialogusage-06.txt> as an Informational RFC
> 
> The IESG plans to make a decision in the next few weeks, and solicits
> final comments on this action.  Please send substantive comments to the
> [e-mail] mailing lists by 2007-05-10. Exceptionally, 
> comments may be sent to [e-mail] instead. In either case, please 
> retain the beginning of the Subject line to allow automated sorting.
> 
> The file can be obtained via
> http://www.ietf.org/internet-drafts/draft-ietf-sipping-dialogusage-06.tx
> t
> 
> 
> IESG discussion can be tracked via
> https://datatracker.ietf.org/public/pidtracker.cgi?command=view_id&dTag=
> 14041&rfc_flag=0
> 
> 
> 
> 
> 
> 
> 
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