[Jingle] Comments on XEP-0251 standard

Diana Cionoiu diana-liste at null.ro
Fri Apr 24 11:03:11 CDT 2009

Hello Dawid,

I disagree with you.
In jingle if Carol wants to avoid Mallory, she will deny the call either 
way because the call request is comming from Mallory. That's the entire 
point, the transfer in jingle does exactly what is says, notify the 
other end where the real destination should be. The rest of the 
verification like for example if Carol is available for Mallory is done 
by other parts of the XMPP protocol. If you want to hide that, you 
should use an intelligent server as you do in SIP with a smart proxy or 
a decent B2BUA.
Anyway for a call center you are suppose to use a B2BUA for other 
several good reasons like early media.

There was a huge effort put into making jingle a better protocol than 
SIP. I believe that it is wrong to make jingle as complicated as SIP.

I know that is hard in the beginning for implementors to handle some of 
the tricky situations, but it's doable. The company I'm working for has 
a jingle PBX with queues support that uses jingle presence and i know 
from experience that it can be done.

Diana Cionoiu

P.S. Please remember that in jingle there is always a server on the way, 
and always Carol is client to a server.

Dawid Nowak wrote:
> Hi,
> This is a grea learning experience :) Anyway I don't think it will make it any safer. To prove the point check "The Session Initiation Protocol (SIP) Refer Method" Section 5.2 Authorization Considerations for REFER. Here is a citation that higlights my point.
> 5.3.1 Circumventing Privacy
>    Suppose Alice has a user agent that accepts REFER requests to SIP
>    INVITE URIs, and NOTIFYs the referrer of the progress of the INVITE
>    by copying each response to the INVITE into the body of a NOTIFY.
>    Suppose further that Carol has a reason to avoid Mallory and has
>    configured her system at her proxy to only accept calls from a
>    certain set of people she trusts (including Alice), so that Mallory
>    doesn't learn when she's around, or what user agent she's actually
>    using.
>    Mallory can send a REFER to Alice, with a Refer-To URI indicating
>    Carol.  If Alice can reach Carol, the 200 OK Carol sends gets
>    returned to Mallory in a NOTIFY, letting him know not only that Carol
>    is around, but also the IP address of the agent she's using.
> Also SIP relies on Proxies where a proxy can interpret, and, if necessary, rewrite specific parts of a request message before forwarding it. 
> My problem with this is that the protocol is not secure and we have to rely on intelligent servers to make the whole system secure. If the protocol was secured that the intelligent servers could be less intelligent and less complex I think. Also since implementation of servers is not standardized some servers are better than others but as a customer I don't really have knowledge about it. Where as if safety mechanisms are put into the protocol all entities would have to implement the same set of functionality.
> Regards
> D
> -----Original Message-----
> From: jingle-bounces at xmpp.org [mailto:jingle-bounces at xmpp.org] On Behalf Of Unnikrishnan V
> Sent: 23 April 2009 20:18
> To: XMPP Jingle
> Subject: Re: [Jingle] Comments on XEP-0251 standard
> Have look on
> http://www.tech-invite.com/Ti-sip-service-5.html
> and
> http://www.tech-invite.com/Ti-sip-service-4.html
> As  a standard, the missing thing may be the notification after disconnect of the call.
> thanx
> unni

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