[SR-Users] DMQ Usrloc/Dialog - Experiences

[Julien Chavanton]

Hi Carsten, likewise on everything you said !

Good questions, a transaction is used and there will be retransmissions.
In such a case we get the normal transaction retransmission mechanism, if a
node becomes disconnected for a while, it is possible to request a full
sync, from all the other nodes, not very efficient but good for
consistency, a restart will do that.
This is why I added batching, on a LAN with support for jumbo frame this
makes a huge difference. (far less transactions, who can be expensive).
Even with an MTU of 1400 this will reduce the amount of transactions
greatly.

There can be race conditions when we sync/replicate while a
registration/unregistration is in progress (something highlighted by
Torrey) at Kamailio world.
Search the mailing list for "DMQ re-ordering concern", we did raise the
concern if any real significant concern there is in the mailing list.

Let us know what you think.
I think we should iterate and improve/deal with race condition concerns,
this native replication protocol is great IMHO




On Tue, Nov 30, 2021 at 1:31 AM Carsten Bock <carsten at ng-voice.com> wrote:

> Hi Julien,
>
> thanks for your reply - I really appreciate your feedback and your
> presentations at KamailioWorld, I hope to see you again in person soon.
>
> Can you share some details on how many records you synchronize using DMQ
> and if you ever experienced any loss of records while synchronization using
> DMQ? The issue is, that on IMS the registration is typically set to 600000
> seconds (1 week), as we have other mechanisms to get notified if a user is
> dropping out of the network (we get notifications from the LTE network
> itself) and a loss of registration data would result in a user not being
> reachable for a long period of time.
>
> Thanks,
> Carsten
> --
> Carsten Bock I CTO & Founder
>
> ng-voice GmbH
>
> Trostbrücke 1 I 20457 Hamburg I Germany
> T +49 179 2021244 I www.ng-voice.com
>
> Registry Office at Local Court Hamburg, HRB 120189
> Managing Directors: Dr. David Bachmann, Carsten Bock
>
>
> Am Mo., 29. Nov. 2021 um 18:09 Uhr schrieb Julien Chavanton <
> jchavanton at gmail.com>:
>
>> Hi Carsten, from my experience Usrloc + DMQ works very well, rare
>> replication race conditions are insignificant since the state is quite
>> volatile anyway.
>>
>> However you can only have that many nodes, great for clustering.
>>
>> On Mon, Nov 29, 2021 at 6:47 AM Carsten Bock <carsten at ng-voice.com>
>> wrote:
>>
>>> Hi,
>>>
>>> I wanted to quickly ask the group about experiences with DMQ and
>>> Usrloc/Dialog.
>>>
>>> I don't expect any issues when choosing such an approach, especially
>>> since we would have re-transmits for a message (fr_timer = 30 seconds) if
>>> we did not receive any answers or scenarios alike. So I assume, having
>>> short "outages" (less than 30 seconds) for the communication is just fine.
>>>
>>> So far I used DMQ in a non-IMS setup for synchronizing usrloc with ~15k
>>> Subscribers and it worked really well.
>>>
>>> One concern brought up (not by me) was, that synchronizing usrloc with
>>> DMQ might not be reliable at scale. I would also love to understand how to
>>> treat situations when the communication is lost for a longer period of time
>>> (e.g. if the communication between nodes is lost for 5 minutes?).
>>>
>>> Can anyone share some real-life experiences?
>>>
>>> Thanks,
>>> Carsten
>>>
>>>
>>>
>>>
>>> --
>>> Carsten Bock I CTO & Founder
>>>
>>> ng-voice GmbH
>>>
>>> Trostbrücke 1 I 20457 Hamburg I Germany
>>> T +49 179 2021244 I www.ng-voice.com
>>>
>>> Registry Office at Local Court Hamburg, HRB 120189
>>> Managing Directors: Dr. David Bachmann, Carsten Bock
>>> __________________________________________________________
>>> Kamailio - Users Mailing List - Non Commercial Discussions
>>>   * sr-users at lists.kamailio.org
>>> Important: keep the mailing list in the recipients, do not reply only to
>>> the sender!
>>> Edit mailing list options or unsubscribe:
>>>   * https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
>>>
>> __________________________________________________________
>> Kamailio - Users Mailing List - Non Commercial Discussions
>>   * sr-users at lists.kamailio.org
>> Important: keep the mailing list in the recipients, do not reply only to
>> the sender!
>> Edit mailing list options or unsubscribe:
>>   * https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
>>
> __________________________________________________________
> Kamailio - Users Mailing List - Non Commercial Discussions
>   * sr-users at lists.kamailio.org
> Important: keep the mailing list in the recipients, do not reply only to
> the sender!
> Edit mailing list options or unsubscribe:
>   * https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.kamailio.org/pipermail/sr-users/attachments/20211130/babcf20d/attachment.htm>