Hi all,
What I’m trying to achieve is to have Kamailio fork an INVITE to multiple endpoints in parallel but only maintain the branch that responds first (first to respond with 200 OK I guess).
I’ve read the TM module documentation on forking (https://www.kamailio.org/docs/modules/stable/modules/tm.html#tm.serial_forki... https://www.kamailio.org/docs/modules/stable/modules/tm.html#tm.serial_forking) and as far as I understood a combination of “seturi()” + “append_branch()” + “t_relay()” command calls will allow me to send multiple forked INVITEs in parallel.
What I couldn't find information about in the documentation (please point me to it in case I missed it) is what controls (if any) do I have over forked requests. Do I need to keep track of the branches myself and cancel others when first succeeds or does Kamailio have some kind of setting for implementing such behaviour?
Thanks, Ivan
On 20 Apr 2020, at 10:31, Ivan Ribakov i.ribakov@zaleos.net wrote:
Hi all,
What I’m trying to achieve is to have Kamailio fork an INVITE to multiple endpoints in parallel but only maintain the branch that responds first (first to respond with 200 OK I guess).
I’ve read the TM module documentation on forking (https://www.kamailio.org/docs/modules/stable/modules/tm.html#tm.serial_forki... https://www.kamailio.org/docs/modules/stable/modules/tm.html#tm.serial_forking) and as far as I understood a combination of “seturi()” + “append_branch()” + “t_relay()” command calls will allow me to send multiple forked INVITEs in parallel.
What I couldn't find information about in the documentation (please point me to it in case I missed it) is what controls (if any) do I have over forked requests. Do I need to keep track of the branches myself and cancel others when first succeeds or does Kamailio have some kind of setting for implementing such behaviour?
It’s all implemented according to the RFC 3261 where you can read all the cool details!
/O
As far as I understand, RFC3261 is not providing any instructions on how to deal with forked INVITES specifically. It just says that forking can result in multiple dialogs that are part of the same original call. I couldn’t find any prescriptions on how/when to deal with these multiple dialogs specifically which makes me think it depends on the application. Once again, please correct me if I’m wrong.
So, in the same way as RFC3261 is not talking about forked INVITE priorities or parallelism, but Kamailio (TM module) is providing a mechanism for forking in parallel/serial modes (advanced feature that is not part of RFC3261, but is built on top of it), I’m wondering whether Kamailio (TM module) is providing any advanced features for dealing with forked INVITE responses.
Thanks, Ivan
On 20 Apr 2020, at 11:13, Olle E. Johansson oej@edvina.net wrote:
On 20 Apr 2020, at 10:31, Ivan Ribakov <i.ribakov@zaleos.net mailto:i.ribakov@zaleos.net> wrote:
Hi all,
What I’m trying to achieve is to have Kamailio fork an INVITE to multiple endpoints in parallel but only maintain the branch that responds first (first to respond with 200 OK I guess).
I’ve read the TM module documentation on forking (https://www.kamailio.org/docs/modules/stable/modules/tm.html#tm.serial_forki... https://www.kamailio.org/docs/modules/stable/modules/tm.html#tm.serial_forking) and as far as I understood a combination of “seturi()” + “append_branch()” + “t_relay()” command calls will allow me to send multiple forked INVITEs in parallel.
What I couldn't find information about in the documentation (please point me to it in case I missed it) is what controls (if any) do I have over forked requests. Do I need to keep track of the branches myself and cancel others when first succeeds or does Kamailio have some kind of setting for implementing such behaviour?
It’s all implemented according to the RFC 3261 where you can read all the cool details!
/O
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org mailto:sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Maybe is not very explicit, but I believe section 16.7(10) of RFC 3261 deal with it (sends CANCEL to branches) -giovanni
On Mon, Apr 20, 2020 at 11:48 AM Ivan Ribakov i.ribakov@zaleos.net wrote:
As far as I understand, RFC3261 is not providing any instructions on how to deal with forked INVITES specifically. It just says that forking can result in multiple dialogs that are part of the same original call. I couldn’t find any prescriptions on how/when to deal with these multiple dialogs specifically which makes me think it depends on the application. Once again, please correct me if I’m wrong.
So, in the same way as RFC3261 is not talking about forked INVITE priorities or parallelism, but Kamailio (TM module) is providing a mechanism for forking in parallel/serial modes (advanced feature that is not part of RFC3261, but is built on top of it), I’m wondering whether Kamailio (TM module) is providing any advanced features for dealing with forked INVITE responses.
Thanks, Ivan
On 20 Apr 2020, at 11:13, Olle E. Johansson oej@edvina.net wrote:
On 20 Apr 2020, at 10:31, Ivan Ribakov i.ribakov@zaleos.net wrote:
Hi all,
What I’m trying to achieve is to have Kamailio fork an INVITE to multiple endpoints in parallel but only maintain the branch that responds first (first to respond with 200 OK I guess).
I’ve read the TM module documentation on forking ( https://www.kamailio.org/docs/modules/stable/modules/tm.html#tm.serial_forki...) and as far as I understood a combination of “seturi()” + “append_branch()”
- “t_relay()” command calls will allow me to send multiple forked INVITEs
in parallel.
What I couldn't find information about in the documentation (please point me to it in case I missed it) is what controls (if any) do I have over forked requests. Do I need to keep track of the branches myself and cancel others when first succeeds or does Kamailio have some kind of setting for implementing such behaviour?
It’s all implemented according to the RFC 3261 where you can read all the cool details!
/O
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
( and is implemented in automatic: when receive the 200 OK for a branch (the winning one), Kamailio sends CANCEL to the other branches )
On Mon, Apr 20, 2020 at 12:48 PM Giovanni Maruzzelli gmaruzz@gmail.com wrote:
Maybe is not very explicit, but I believe section 16.7(10) of RFC 3261 deal with it (sends CANCEL to branches) -giovanni
On Mon, Apr 20, 2020 at 11:48 AM Ivan Ribakov i.ribakov@zaleos.net wrote:
As far as I understand, RFC3261 is not providing any instructions on how to deal with forked INVITES specifically. It just says that forking can result in multiple dialogs that are part of the same original call. I couldn’t find any prescriptions on how/when to deal with these multiple dialogs specifically which makes me think it depends on the application. Once again, please correct me if I’m wrong.
So, in the same way as RFC3261 is not talking about forked INVITE priorities or parallelism, but Kamailio (TM module) is providing a mechanism for forking in parallel/serial modes (advanced feature that is not part of RFC3261, but is built on top of it), I’m wondering whether Kamailio (TM module) is providing any advanced features for dealing with forked INVITE responses.
Thanks, Ivan
On 20 Apr 2020, at 11:13, Olle E. Johansson oej@edvina.net wrote:
On 20 Apr 2020, at 10:31, Ivan Ribakov i.ribakov@zaleos.net wrote:
Hi all,
What I’m trying to achieve is to have Kamailio fork an INVITE to multiple endpoints in parallel but only maintain the branch that responds first (first to respond with 200 OK I guess).
I’ve read the TM module documentation on forking ( https://www.kamailio.org/docs/modules/stable/modules/tm.html#tm.serial_forki...) and as far as I understood a combination of “seturi()” + “append_branch()”
- “t_relay()” command calls will allow me to send multiple forked INVITEs
in parallel.
What I couldn't find information about in the documentation (please point me to it in case I missed it) is what controls (if any) do I have over forked requests. Do I need to keep track of the branches myself and cancel others when first succeeds or does Kamailio have some kind of setting for implementing such behaviour?
It’s all implemented according to the RFC 3261 where you can read all the cool details!
/O
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
-- Sincerely,
Giovanni Maruzzelli OpenTelecom.IT cell: +39 347 266 56 18
Thanks for pointing me to the specific section, Giovanni! I was searching RFC for the “fork” and “merge” keywords so I never got even close to this part of RFC.
On 20 Apr 2020, at 13:27, Giovanni Maruzzelli <gmaruzz@gmail.com mailto:gmaruzz@gmail.com> wrote:
( and is implemented in automatic: when receive the 200 OK for a branch (the winning one), Kamailio sends CANCEL to the other branches )
On Mon, Apr 20, 2020 at 12:48 PM Giovanni Maruzzelli <gmaruzz@gmail.com mailto:gmaruzz@gmail.com> wrote: Maybe is not very explicit, but I believe section 16.7(10) of RFC 3261 deal with it (sends CANCEL to branches) -giovanni
On Mon, Apr 20, 2020 at 11:48 AM Ivan Ribakov <i.ribakov@zaleos.net mailto:i.ribakov@zaleos.net> wrote: As far as I understand, RFC3261 is not providing any instructions on how to deal with forked INVITES specifically. It just says that forking can result in multiple dialogs that are part of the same original call. I couldn’t find any prescriptions on how/when to deal with these multiple dialogs specifically which makes me think it depends on the application. Once again, please correct me if I’m wrong.
So, in the same way as RFC3261 is not talking about forked INVITE priorities or parallelism, but Kamailio (TM module) is providing a mechanism for forking in parallel/serial modes (advanced feature that is not part of RFC3261, but is built on top of it), I’m wondering whether Kamailio (TM module) is providing any advanced features for dealing with forked INVITE responses.
Thanks, Ivan
On 20 Apr 2020, at 11:13, Olle E. Johansson <oej@edvina.net mailto:oej@edvina.net> wrote:
On 20 Apr 2020, at 10:31, Ivan Ribakov <i.ribakov@zaleos.net mailto:i.ribakov@zaleos.net> wrote:
Hi all,
What I’m trying to achieve is to have Kamailio fork an INVITE to multiple endpoints in parallel but only maintain the branch that responds first (first to respond with 200 OK I guess).
I’ve read the TM module documentation on forking (https://www.kamailio.org/docs/modules/stable/modules/tm.html#tm.serial_forki... https://www.kamailio.org/docs/modules/stable/modules/tm.html#tm.serial_forking) and as far as I understood a combination of “seturi()” + “append_branch()” + “t_relay()” command calls will allow me to send multiple forked INVITEs in parallel.
What I couldn't find information about in the documentation (please point me to it in case I missed it) is what controls (if any) do I have over forked requests. Do I need to keep track of the branches myself and cancel others when first succeeds or does Kamailio have some kind of setting for implementing such behaviour?
It’s all implemented according to the RFC 3261 where you can read all the cool details!
/O
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org mailto:sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org mailto:sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
-- Sincerely,
Giovanni Maruzzelli OpenTelecom.IT cell: +39 347 266 56 18
-- Sincerely,
Giovanni Maruzzelli OpenTelecom.IT cell: +39 347 266 56 18
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org mailto:sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Shouldn’t 183 also be a “final” response in regards to branching?
On Mon, 20 Apr 2020 at 14:32, Ivan Ribakov i.ribakov@zaleos.net wrote:
Thanks for pointing me to the specific section, Giovanni! I was searching RFC for the “fork” and “merge” keywords so I never got even close to this part of RFC.
On 20 Apr 2020, at 13:27, Giovanni Maruzzelli gmaruzz@gmail.com wrote:
( and is implemented in automatic: when receive the 200 OK for a branch (the winning one), Kamailio sends CANCEL to the other branches )
On Mon, Apr 20, 2020 at 12:48 PM Giovanni Maruzzelli gmaruzz@gmail.com wrote:
Maybe is not very explicit, but I believe section 16.7(10) of RFC 3261 deal with it (sends CANCEL to branches) -giovanni
On Mon, Apr 20, 2020 at 11:48 AM Ivan Ribakov i.ribakov@zaleos.net wrote:
As far as I understand, RFC3261 is not providing any instructions on how to deal with forked INVITES specifically. It just says that forking can result in multiple dialogs that are part of the same original call. I couldn’t find any prescriptions on how/when to deal with these multiple dialogs specifically which makes me think it depends on the application. Once again, please correct me if I’m wrong.
So, in the same way as RFC3261 is not talking about forked INVITE priorities or parallelism, but Kamailio (TM module) is providing a mechanism for forking in parallel/serial modes (advanced feature that is not part of RFC3261, but is built on top of it), I’m wondering whether Kamailio (TM module) is providing any advanced features for dealing with forked INVITE responses.
Thanks, Ivan
On 20 Apr 2020, at 11:13, Olle E. Johansson oej@edvina.net wrote:
On 20 Apr 2020, at 10:31, Ivan Ribakov i.ribakov@zaleos.net wrote:
Hi all,
What I’m trying to achieve is to have Kamailio fork an INVITE to multiple endpoints in parallel but only maintain the branch that responds first (first to respond with 200 OK I guess).
I’ve read the TM module documentation on forking ( https://www.kamailio.org/docs/modules/stable/modules/tm.html#tm.serial_forki...) and as far as I understood a combination of “seturi()” + “append_branch()”
- “t_relay()” command calls will allow me to send multiple forked INVITEs
in parallel.
What I couldn't find information about in the documentation (please point me to it in case I missed it) is what controls (if any) do I have over forked requests. Do I need to keep track of the branches myself and cancel others when first succeeds or does Kamailio have some kind of setting for implementing such behaviour?
It’s all implemented according to the RFC 3261 where you can read all the cool details!
/O
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
-- Sincerely,
Giovanni Maruzzelli OpenTelecom.IT cell: +39 347 266 56 18
-- Sincerely,
Giovanni Maruzzelli OpenTelecom.IT cell: +39 347 266 56 18
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Just thought of a follow up question - is it possible to find out which of the branches Kamailio chose as the winner? According to RFC multiple 200 OK could arrive before CANCEL is sent. Do I need to look for an outgoing ACK to know for sure which branch was chosen for sure or is there a way I could “catch” a winning branch through some sort of custom branch route (thinking along the lines of “t_on_branch_success”)?
Thanks, Ivan
On 20 Apr 2020, at 15:28, Ivan Ribakov i.ribakov@zaleos.net wrote:
Thanks for pointing me to the specific section, Giovanni! I was searching RFC for the “fork” and “merge” keywords so I never got even close to this part of RFC.
On 20 Apr 2020, at 13:27, Giovanni Maruzzelli <gmaruzz@gmail.com mailto:gmaruzz@gmail.com> wrote:
( and is implemented in automatic: when receive the 200 OK for a branch (the winning one), Kamailio sends CANCEL to the other branches )
On Mon, Apr 20, 2020 at 12:48 PM Giovanni Maruzzelli <gmaruzz@gmail.com mailto:gmaruzz@gmail.com> wrote: Maybe is not very explicit, but I believe section 16.7(10) of RFC 3261 deal with it (sends CANCEL to branches) -giovanni
On Mon, Apr 20, 2020 at 11:48 AM Ivan Ribakov <i.ribakov@zaleos.net mailto:i.ribakov@zaleos.net> wrote: As far as I understand, RFC3261 is not providing any instructions on how to deal with forked INVITES specifically. It just says that forking can result in multiple dialogs that are part of the same original call. I couldn’t find any prescriptions on how/when to deal with these multiple dialogs specifically which makes me think it depends on the application. Once again, please correct me if I’m wrong.
So, in the same way as RFC3261 is not talking about forked INVITE priorities or parallelism, but Kamailio (TM module) is providing a mechanism for forking in parallel/serial modes (advanced feature that is not part of RFC3261, but is built on top of it), I’m wondering whether Kamailio (TM module) is providing any advanced features for dealing with forked INVITE responses.
Thanks, Ivan
On 20 Apr 2020, at 11:13, Olle E. Johansson <oej@edvina.net mailto:oej@edvina.net> wrote:
On 20 Apr 2020, at 10:31, Ivan Ribakov <i.ribakov@zaleos.net mailto:i.ribakov@zaleos.net> wrote:
Hi all,
What I’m trying to achieve is to have Kamailio fork an INVITE to multiple endpoints in parallel but only maintain the branch that responds first (first to respond with 200 OK I guess).
I’ve read the TM module documentation on forking (https://www.kamailio.org/docs/modules/stable/modules/tm.html#tm.serial_forki... https://www.kamailio.org/docs/modules/stable/modules/tm.html#tm.serial_forking) and as far as I understood a combination of “seturi()” + “append_branch()” + “t_relay()” command calls will allow me to send multiple forked INVITEs in parallel.
What I couldn't find information about in the documentation (please point me to it in case I missed it) is what controls (if any) do I have over forked requests. Do I need to keep track of the branches myself and cancel others when first succeeds or does Kamailio have some kind of setting for implementing such behaviour?
It’s all implemented according to the RFC 3261 where you can read all the cool details!
/O
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org mailto:sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org mailto:sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
-- Sincerely,
Giovanni Maruzzelli OpenTelecom.IT cell: +39 347 266 56 18
-- Sincerely,
Giovanni Maruzzelli OpenTelecom.IT cell: +39 347 266 56 18
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org mailto:sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
That is the reply route.
Start testing and adding logging.
The case with multiple 200 OK is something we have tested many times. The proxy should NOT try to do anything in that case, just forward the multiple 200 OK to the caller and let the UA decide what to do. The UA needs to ACK both, and if it can’t somehow handle multiple calls, send a BYE to one of them.
/O
On 20 Apr 2020, at 15:55, Ivan Ribakov i.ribakov@zaleos.net wrote:
Just thought of a follow up question - is it possible to find out which of the branches Kamailio chose as the winner? According to RFC multiple 200 OK could arrive before CANCEL is sent. Do I need to look for an outgoing ACK to know for sure which branch was chosen for sure or is there a way I could “catch” a winning branch through some sort of custom branch route (thinking along the lines of “t_on_branch_success”)?
Thanks, Ivan
On 20 Apr 2020, at 15:28, Ivan Ribakov <i.ribakov@zaleos.net mailto:i.ribakov@zaleos.net> wrote:
Thanks for pointing me to the specific section, Giovanni! I was searching RFC for the “fork” and “merge” keywords so I never got even close to this part of RFC.
On 20 Apr 2020, at 13:27, Giovanni Maruzzelli <gmaruzz@gmail.com mailto:gmaruzz@gmail.com> wrote:
( and is implemented in automatic: when receive the 200 OK for a branch (the winning one), Kamailio sends CANCEL to the other branches )
On Mon, Apr 20, 2020 at 12:48 PM Giovanni Maruzzelli <gmaruzz@gmail.com mailto:gmaruzz@gmail.com> wrote: Maybe is not very explicit, but I believe section 16.7(10) of RFC 3261 deal with it (sends CANCEL to branches) -giovanni
On Mon, Apr 20, 2020 at 11:48 AM Ivan Ribakov <i.ribakov@zaleos.net mailto:i.ribakov@zaleos.net> wrote: As far as I understand, RFC3261 is not providing any instructions on how to deal with forked INVITES specifically. It just says that forking can result in multiple dialogs that are part of the same original call. I couldn’t find any prescriptions on how/when to deal with these multiple dialogs specifically which makes me think it depends on the application. Once again, please correct me if I’m wrong.
So, in the same way as RFC3261 is not talking about forked INVITE priorities or parallelism, but Kamailio (TM module) is providing a mechanism for forking in parallel/serial modes (advanced feature that is not part of RFC3261, but is built on top of it), I’m wondering whether Kamailio (TM module) is providing any advanced features for dealing with forked INVITE responses.
Thanks, Ivan
On 20 Apr 2020, at 11:13, Olle E. Johansson <oej@edvina.net mailto:oej@edvina.net> wrote:
On 20 Apr 2020, at 10:31, Ivan Ribakov <i.ribakov@zaleos.net mailto:i.ribakov@zaleos.net> wrote:
Hi all,
What I’m trying to achieve is to have Kamailio fork an INVITE to multiple endpoints in parallel but only maintain the branch that responds first (first to respond with 200 OK I guess).
I’ve read the TM module documentation on forking (https://www.kamailio.org/docs/modules/stable/modules/tm.html#tm.serial_forki... https://www.kamailio.org/docs/modules/stable/modules/tm.html#tm.serial_forking) and as far as I understood a combination of “seturi()” + “append_branch()” + “t_relay()” command calls will allow me to send multiple forked INVITEs in parallel.
What I couldn't find information about in the documentation (please point me to it in case I missed it) is what controls (if any) do I have over forked requests. Do I need to keep track of the branches myself and cancel others when first succeeds or does Kamailio have some kind of setting for implementing such behaviour?
It’s all implemented according to the RFC 3261 where you can read all the cool details!
/O
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org mailto:sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org mailto:sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
-- Sincerely,
Giovanni Maruzzelli OpenTelecom.IT cell: +39 347 266 56 18
-- Sincerely,
Giovanni Maruzzelli OpenTelecom.IT cell: +39 347 266 56 18
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org mailto:sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
It should be noted at a rather general level that parallel forking is replete with race conditions, and is a nasty and unwieldy aspect of SIP.
The pain of using parallel forking to implement something like "ring groups", for example, is often not worth the savings in architectural complexity.
If you have some other means of accomplishing what you want to accomplish, e.g. using a B2BUA to generate multiple independent call legs simultaneously ringing multiple destinations, I strongly advise you to go with that instead.
-- Alex
Hi Alex,
Isn't the option of generating multiple call legs with a B2BUA more subject to dead air/ghost calls than letting kamailio handle parallel forking?
Nuno
On Tue, Apr 21, 2020 at 12:06 AM Alex Balashov abalashov@evaristesys.com wrote:
It should be noted at a rather general level that parallel forking is replete with race conditions, and is a nasty and unwieldy aspect of SIP.
The pain of using parallel forking to implement something like "ring groups", for example, is often not worth the savings in architectural complexity.
If you have some other means of accomplishing what you want to accomplish, e.g. using a B2BUA to generate multiple independent call legs simultaneously ringing multiple destinations, I strongly advise you to go with that instead.
-- Alex
-- Alex Balashov | Principal | Evariste Systems LLC
Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free) Web: http://www.evaristesys.com/, http://www.csrpswitch.com/
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
The main gain in using a B2BUA is that you take responsibility for terminating the extra call legs, it is as good as your B2BUA will be, by delegating the responsibility upstream you can not always be sure it is handled properly.
I wonder if Kamailio should consider evolving in B2BUA support. I am expecting to receive tomatoes.
On Tue, Apr 21, 2020 at 3:50 AM Nuno Ferreira nferreira@fuze.com wrote:
Hi Alex,
Isn't the option of generating multiple call legs with a B2BUA more subject to dead air/ghost calls than letting kamailio handle parallel forking?
Nuno
On Tue, Apr 21, 2020 at 12:06 AM Alex Balashov abalashov@evaristesys.com wrote:
It should be noted at a rather general level that parallel forking is replete with race conditions, and is a nasty and unwieldy aspect of SIP.
The pain of using parallel forking to implement something like "ring groups", for example, is often not worth the savings in architectural complexity.
If you have some other means of accomplishing what you want to accomplish, e.g. using a B2BUA to generate multiple independent call legs simultaneously ringing multiple destinations, I strongly advise you to go with that instead.
-- Alex
-- Alex Balashov | Principal | Evariste Systems LLC
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You are right that this is not very explicit.
Kamailio will cancel automatically once one branch connects but if it failed to cancel (meaning other branches connects) The originiting UAC will have to disconnect the extra calls.
Which is something that is handled properly by most if not all.
On Mon, Apr 20, 2020, 01:31 Ivan Ribakov i.ribakov@zaleos.net wrote:
Hi all,
What I’m trying to achieve is to have Kamailio fork an INVITE to multiple endpoints in parallel but only maintain the branch that responds first (first to respond with 200 OK I guess).
I’ve read the TM module documentation on forking ( https://www.kamailio.org/docs/modules/stable/modules/tm.html#tm.serial_forki...) and as far as I understood a combination of “seturi()” + “append_branch()”
- “t_relay()” command calls will allow me to send multiple forked INVITEs
in parallel.
What I couldn't find information about in the documentation (please point me to it in case I missed it) is what controls (if any) do I have over forked requests. Do I need to keep track of the branches myself and cancel others when first succeeds or does Kamailio have some kind of setting for implementing such behaviour?
Thanks, Ivan _______________________________________________ Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
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