Thanks Tony.

   You're correct, I would not like to hear 'use Polycom handsets', as the same 
issue exists for me using Grandstream, Snom, and Counterpath softphone UAs, but 
specifically because I have already deployed over 100 Grandstream handsets in 
production, and have another 370 on hand, ready to deploy.

   It seems that you and I are at an impasse with a difference of opinion 
regarding a SIP Proxy server.

   The SipXecs proxy server ALREADY checks REFER-TO requests against the 
permissions, to see if a user is ALLOWED to forward to the number attempted, 
which is what results in the authentication packets before the REFER-TO is 
passed on.  It WELL within the scope of the proxy to update/modify the packet 
when if forwards the REFER-TO request after it has taken the time and network 
packets to challenge and authenticate the transfer request.  The SipXecs proxy 
does not blindly forward the REFER-TO request, rather it creates a NEW request, 
and sends it on.

   Adding an SBC, or reconfiguring the Patton to act as a B2BUA, simply to 
overcome a single transfer issue, doesn't seem even close to reasonable.  You 
told me I was over complicating it already :)

Cheers,

...Steve...



From: [email protected] 
[mailto:[email protected]] On Behalf Of Tony Graziano
Sent: Wednesday, September 07, 2011 2:41 PM
To: Discussion list for users of sipXecs software
Subject: Re: [sipx-users] Transfer troubles : REFER-TO not routed/modified 
according to the dialplan


you don't. you do if you don't have something parsing or rewriting it 
correctly., or is incapable of doing it.

sipx is a proxy. if you are connecting as an unmanaged gateway, this should 
work fine. at the same tine I ha e seen this dine with older necessary pbx 
systems and have not heard of call transfer issues.

you could also set this up as a siptrunk or as a b2bua in the patton with the 
patton essentially registering to sipx.

I would not curry favor with you in suggesting to use a polycom handset as the 
sipx ua, which is the only way I have seen it done. sometimes the least common. 
component (ua) poses the greatest difficulty. you might inquire of patron 
whether they can make you a b2ua on the patton to be the middle ma.  between 
the two systems.
On Sep 7, 2011 5:33 PM, "Steve Beaudry" 
<[email protected]<mailto:[email protected]>> wrote:
> You realize that in the case of a dialed call (if a SipXecs user picks up a 
> grandstream phone and dials) to 4495, the SipXecs server DOES rewrite the 
> headers, and the rules exist on the patton to route the call correctly?
>
> I'm afraid that I don't understand why I should need an SBC simply to handle 
> a transfer between two systems, when dialing back and forth between those 
> systems works properly.
>
> From: 
> [email protected]<mailto:[email protected]>
>  
> [mailto:[email protected]<mailto:[email protected]>]
>  On Behalf Of Tony Graziano
> Sent: Wednesday, September 07, 2011 2:27 PM
> To: Discussion list for users of sipXecs software
> Subject: Re: [sipx-users] Transfer troubles : REFER-TO not routed/modified 
> according to the dialplan
>
>
> I think its important to say that sipx and sipxbridge as an sbc is designed 
> to handle pstn sip trunks.
> I think you expect sipx and an unmanaged gateway to do more than they should.
>
> I do think with the patton handles a refer properly. I don't think id expect 
> sipx or the patton to rewrite the header, invite or refer. you would need an 
> sbc to do that.
>
> at the same time if 4495 is dialed and sent to the patton I think a match 
> rule can be in applied on it to make sure it gets handled properly. i expect 
> the patton engineer you are speaking with can probably pull this off.
> On Sep 7, 2011 5:17 PM, "Steve Beaudry" 
> <[email protected]<mailto:[email protected]><mailto:[email protected]<mailto:[email protected]>>>
>  wrote:
>>
>> Content-Type: text/plain;
>> charset="utf-8"
>> Content-Transfer-Encoding: 8bit
>> Organization: SipXecs Forum
>> In-Reply-To: 
>> <CAMgKNJWQao0SctwLUTHgeO610cdARSWkxW22LTgU8n=uyay...@mail.gmail.com<mailto:[email protected]><mailto:[email protected]<mailto:[email protected]>>>
>> X-FUDforum: 08063afcdd00a6e76393c5b9527381e8 <63116>
>> Message-ID: 
>> <[email protected]<mailto:[email protected]><mailto:[email protected]<mailto:[email protected]>>>
>>
>>
>>
>> Hi Tony,
>>
>> So, in reading, re-reading, and re-evaluating things
>> based on what you and others here have said, I think I've
>> realized that the scope of affected transfers is smaller
>> than I thought (although, still critical for us).
>>
>> The issue only occurs when a call comes in through the
>> patton gateway, to a SipXecs extension, which is
>> subsequently transferred/forwarded to an extension that is
>> only reachable back via the Patton gateway. I believe I've
>> seen this referred to as a 'hairpin' call.
>>
>> As you mentioned, you thought the difference (routing
>> looking, and therefore the URI transition) should happen
>> during the INVITE. This certainly works in all cases where
>> the call is initiated on the SipXecs server (ie. using one
>> of the SipXecs registered endpoints), but in this case, the
>> PATTON is responsible for creating the INVITE in response to
>> the transfer, not the SipXecs server. You can see this
>> behaviour at line 521 of the 'External to VoIP DID
>> transferred to Nortel extension.txt' file I attached
>> earlier.
>>
>> The Patton is doing exactly as it is instructed in the
>> REFER-TO request, and attempting to transfer the call to
>> mailto:'[email protected]<mailto:[email protected]><mailto:[email protected]<mailto:[email protected]>>'.
>>
>>
>>
>> On the somewhat separate topic of preceeding 4-digit
>> extension numbers with a '99' when dialed, you're right, in
>> hindsight, we could have done without it. This was as much
>> to help with our Nortel dialplan as anything. It does not
>> affect the current issue (the transfer doesn't work if I try
>> to transfer to 994495 either), and I simply pointed it out
>> to give another indication as to where the trouble existed.
>> I should also point out that this works quite well, and is
>> well within the realm of 'correct configuration', done via
>> the standard interface, regardless of whether it's how you
>> would do it or not. It is completely transparent to the end
>> user.
>>
>> What I'm hearing from you is, the SipXecs server does NOT
>> lookup/translate/modify numbers in REFER-TO packets, because
>> it is believed that any translation can be handled during
>> the resulting INVITE. I believe that, in the case of
>> 'hairpin transfers', where the SipXecs server is NOT
>> responsible for creating the INVITE resulting from a
>> REFER-TO, this approach falls short.
>>
>> ...Steve...
>> _______________________________________________
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