[SIPForum-discussion] Route advance query

Mon Oct 27 17:12:38 UTC 2008

Hi Ankit,

It is actually independent of the message, if there is SDP in message
(180 with SDP or 183 with SDP) and if the media is relayed through SBC,
then it will stop hunting.  If there is no SDP, in your example 180 and
getting release code would enable hunting.  But concerning 18x messages
itself contains call state information (Ringing, Buzzed, etc), it would
still stop hunting.  I can't understand why your remote gateway sends
503 after sending 18x messages.  It should turn something like 480 or
486, etc.   

Thinking logically here will help you why Nextone stops hunting.  If
there is an indication of called party's status (like busy, temporarily
unavailable, no answer, etc), hunting shouldn't be performed as Calling
party has information on Called party's state.  Then, Calling party
shouldn't get same information multiple times.

Let me know if you have questions.

Thanks,

Huseyin

From: Ankit [mailto:erankitkumar at gmail.com] 
Sent: Monday, October 27, 2008 7:01 PM
To: Huseyin ALTUN
Cc: Mishra2, Abhishek (NSN - IN/Bangalore); Cirlincione, Sandra;
discussion at sipforum.org; discussion at sipforum.com
Subject: Re: [SIPForum-discussion] Route advance query

Hi Huseyin,

Thanks for your explanation.

Then i think receiving 183 is the cause of the problem which is creating
early media and disabling the route advance (Hunt). If we get simply
180, then after getting 180 and then the release code will make the
route advance (hunt) still enable, but 183 will disable it.

What do you think?

-- 
Thanks and Regards,
Ankit Kumar

2008/10/26 Huseyin ALTUN <huseyin.altun at verscom.com>

Hi Ankit,

If 18x has SDP and media is received (on SBC and source side), means
caller receives an information about callee, like an Operator message,
and then any response (4xx and 5xx) is received, re-routing should be
stopped.  If no media is received, then as Abhishek and Sandra
mentioned, alternate routes would be tried.

Thanks,

Huseyin 

From: discussion-bounces at sipforum.org
[mailto:discussion-bounces at sipforum.org] On Behalf Of Mishra2, Abhishek
(NSN - IN/Bangalore)
Sent: Saturday, October 25, 2008 8:15 PM
To: ext Ankit; Cirlincione, Sandra

Cc: discussion at sipforum.org; discussion at sipforum.com
Subject: Re: [SIPForum-discussion] Route advance query

Hi Ankit

 Till the call is successful (origin gets 200 OK) , the alternate route
should not be discarded.  As Sandra mentioned,18x can happen due to
hetrogeneous network. Tags are useful for such calls

Thanks & Regards

Abhishek

________________________________

From: discussion-bounces at sipforum.org
[mailto:discussion-bounces at sipforum.org] On Behalf Of ext Ankit
Sent: Friday, October 24, 2008 11:45 PM
To: Cirlincione, Sandra
Cc: discussion at sipforum.org; discussion at sipforum.com
Subject: Re: [SIPForum-discussion] Route advance query

Sandra,

Its a problem of a Voice call

Call flow is like:-

Clients GW<------->Our SBC<------->Vendor GW

Our SBC legs are:-

Leg1-- clients GW<----Our SBC
Leg2-- Our SBC<----Vendor GW

Call flow between Our SBC and Vendor GW is:-

Our SBC                                           Vendor GW
                     Invite.....>
                    <100 trying..........
                    <180/183..............
                    < 503 service unavailable----------------

As, you can see above that vendor is sending us 180 and then 503. So my
concern is that will my SBC do any route advance for my client for the
same Call-id, if my running vendor sends me error code like above?

-- 
Thanks and Regards,
Ankit Kumar

2008/10/24 Cirlincione, Sandra <sandra.cirlincione at boeing.com>

This sounds like you have an intermediate device that is providing the
18x response.  If that's the case, then the device that is providing the
18x response, should also be receiving the 503, and would then reroute
on its alternate path, not return the 503 back to the vendor.  The other
condition is that you may get one leg connectivity, with a one-way
conversation, without the other side terminating.

What we saw, was that we only received the 503 if the 18x could not
complete. If the 18x completed, but the call could still not be
connected, then we saw a 200 Ok message, but the call was not connected,
and we received a fast busy on the caller side.

Are you doing voice only, or a mix of other media?

Sandra.Cirlincione @boeing.com 
SSG - IT, Enterprise Voice Engineering, VoIP/Convergence 
MOC pilot 425.865.3214    (One number reach) 

Home Office 425.373.8293 
Desk  206.766.5888
Cell 425.417.3138 
Wishing you happiness, hope, or health, take what you need. 

From: Ankit [mailto:erankitkumar at gmail.com] 
Sent: Friday, October 24, 2008 10:01 AM
To: Cirlincione, Sandra
Cc: discussion at sipforum.org; discussion at sipforum.com 

Subject: Re: [SIPForum-discussion] Route advance query

Sandra,

I appreciate your response.

As per the response code, it should definitely do route advance. But my
concern is that will it do route advace, if my vendor sends me the
release code after 18X......not after 100 trying message.

Concern is that once 18X is being sent from my vendor side, it indicates
that OLC has been established / or Media path has been established. So
will route advance works, if media path has already been established on
the current vendor?

-- 
Thanks and Regards,
Ankit Kumar

2008/10/24 Cirlincione, Sandra <sandra.cirlincione at boeing.com>

Ankit,

Experience over the last few days with this, would indicate that it will
advance if you have something in your configuration to force the next
route.

A 503 error seems to indicate that the service is not reachable,
unavailable, or cannot complete.  It basically looks like an
"unsuccessful" call attempt which tells your system that the route
you've chosen was not successful.  That reply allows the routing device
to try the next preference route.

Sandra.Cirlincione @boeing.com 
SSG - IT, Enterprise Voice Engineering, VoIP/Convergence 
MOC pilot 425.865.3214    (One number reach) 

Home Office 425.373.8293 
Desk  206.766.5888
Cell 425.417.3138 
Wishing you happiness, hope, or health, take what you need. 

From: discussion-bounces at sipforum.org
[mailto:discussion-bounces at sipforum.org] On Behalf Of Ankit
Sent: Friday, October 24, 2008 2:49 AM
To: discussion at sipforum.com
Subject: Re: [SIPForum-discussion] Route advance query

Can somebody help me out?

-- 
Thanks and Regards,
Ankit Kumar

2008/10/24 Ankit <erankitkumar at gmail.com>

Hi Folks,

I need one suggestion on a query. Scenario is:-

Lets say we have 2 backup vendor on routing. Will the GW or Switch or
SBC do route advance if he gets error (lets say 503 or 34 in ISDN) from
his previous vendor after 18X message?

Ex:-

Invite.....>
<100 trying..........
<180/183..............
< 503 service unavailable----------------

If yes, then why so and if no, why no?

-- 
Thanks and Regards,
Ankit Kumar

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