[OpenSIPS-Users] dispatcher problem

Fri Feb 3 15:53:37 CET 2012

Hi Vlad,

We have many locations with 5-10 phones each. We use applications that require us to keep track of device states continuously for each location. We would prefer to have each location handled by the same Asterisk server both for incoming and outbound calls including registrations and subscriptions. It's more scalable and cleaner this way. If that server goes down, the whole location traffic as a whole moves to the next available server. That's why I need more control over dispatching.

Anyway, instead of using "061002", "061003", "061005", "061006", "061007", "061008", if I use "1", "2", "3", "4", "5", "6", I get a much reasonable distribution (at least for 6 locations I use for testing). For 50+ locations, the results might be different of course.

Thanks,
Matt

Date: Fri, 3 Feb 2012 12:50:25 +0200
From: vladpaiu at opensips.org
To: users at lists.opensips.org
Subject: Re: [OpenSIPS-Users] dispatcher problem

    Hi Matt,

    If you want good distribution, why don't you use instead the
    round-robin or the random dispatcher algorithms? 

    [1] http://www.opensips.org/html/docs/modules/devel/dispatcher.html#id293072

    Regards,

    -- 
Vlad Paiu
OpenSIPS Developer
http://opensips-solutions.org/

    Pe 2/3/2012 2:59 AM, Matt Hamilton a scris:

        Hi Răzvan,

I don't assign any weights, and I use the dispatcher.list file:

        1 sip:x.x.x.11:5060

        1 sip:x.x.x.12:5060

        1 sip:x.x.x.13:5060

          When there are only 2 servers in that file, I always get:

        DBG:dispatcher:ds_select_dst: alg hash [1], id [1] and dispatcher selects the 2nd entry.

        When there are 3 servers - when the dispatcher distributes to
        all 3 servers, I get

        DBG:dispatcher:ds_select_dst:
          alg hash [0], id [0] 
          before it dispatches to server1 (x.x.x.11)

        DBG:dispatcher:ds_select_dst: alg hash [1], id [1] for x.x.x.12
        DBG:dispatcher:ds_select_dst: alg
          hash [2], id [2] for x.x.x.13

        Anyway I did some more tests, and it turns out that the hash
        algorithm is very sensitive to the PV. 

        1. when the input hash_pvar is from this set (my original set
        that gave me problems): "061002"  "061003"  "061005"  "061006" 
        "61007"  "061008"

        Dispatcher splits them:

        Server1: 0

        server2: 6

        2. if I add a 1 in front of my hash PV - so that the new values
        are 1"061002", etc.  (indentation mark is part of the string)

        Server1: 2

        Server2: 4

        3. If I add another character, so that PVs look like x1"061002"

        Server1: 3

        Server2: 3

        3-3 or 2-4 split is OK of course, but the 0-6 split threw me
        off. Is there a "safe" PV (integers, certain combinations, etc.)
        that I can use that will give me the best distribution? I can
        use a lookup table (like dialplan) to get those.

        Thanks,

        Matt

          Date: Fri, 3 Feb 2012 00:36:37 +0200

          From: razvancrainea at opensips.org

          To: users at lists.opensips.org

          Subject: Re: [OpenSIPS-Users] dispatcher problem

          Hi, Matt!

          So for different hashed strings like:

          DBG:dispatcher:ds_hash_pvar: Hashing "061002"!
          you always get the same output:

          DBG:dispatcher:ds_select_dst: alg hash [1], id [1]

          Also, are you assigning different weights for any of the
          Asterisk?

          Regards,

          -- 
Răzvan Crainea
OpenSIPS Developer
http://opensips-solutions.org/

          On 02/03/2012 12:16 AM, Matt Hamilton wrote:

              Hi Răzvan,

Yes, I'm using the same hashing values - the values I assign to the PV are also 
passed to the ds_select_dst correctly as far as I can see. Here is a typical
debug output:

DBG:dispatcher:ds_hash_pvar: Hashing "061002"!
DBG:dispatcher:ds_select_dst: alg hash [1], id [1]
DBG:dispatcher:ds_select_dst: selected [7-1/1] <sip:x.x.x.13:5060>
DBG:dispatcher:ds_select_dst: using entry [1/0]

I ran some test with 3 Asterisk servers with interesting results:

With 3 Asterisk servers specified in dispatcher.list, here is the distribution:

Server1: 061003
Server2: 061002, 061007, 061008
Server3: 061005, 061006

With only Server1 and Server2 specified in dispatcher.list:

Server1: 
Server2: 061002, 061003, 061005, 061006, 61007, 061008

Likewise, with Server1 and Server3, Server3 gets everything.        
          with Server2 and Server3, Server3 gets everything.

Is there anything I can do to fix this (somehow trick the function assuming the way I do is the correct way)?

Thanks,
Matt

                Date: Thu, 2 Feb 2012 22:51:46
                +0200

                From: razvancrainea at opensips.org

                To: users at lists.opensips.org

                Subject: Re: [OpenSIPS-Users] dispatcher problem

                Hi, Matt!

                Are you sure you are not using the same hashing value
                all the time?

                If yes, can you increase your debugging level to 6 and
                provide more information? I would be looking in the
                opensips log for lines that contain the following
                strings: "ds_hash_pvar: Hashing " and "ds_select_dst:
                alg hash ".

                Regards,

                -- 
Răzvan Crainea
OpenSIPS Developer
http://opensips-solutions.org/

                On 02/02/2012 10:15 PM, Matt Hamilton wrote:

                   Hi,

                    I'm using Opensips to dispatch to 2 servers -
                    serverA, serverB. When one of the servers is down,
                    Opensips is dispatching to the active one correctly.
                    However, when both of them are Active, it's picking
                    only one of them and ignoring the other; e.g.,

                    when serverB is down, dispatches to serverA

                    when serverA is down, dispatches to serverB

                    when both up, dispatches to serverB

                    while dispatching to serverA when serverB is down,
                    if I activate serverB, all requests dispatched to
                    serverB  

                    Here is my code:

                    modparam("dispatcher", "hash_pvar", "$avp(75)")

                    in the script, I'm setting $avp(75) to one of the
                    following "061002", "061003", "061004", "061005",
                    "061006" just before calling ds_select_dst.

                    $avp(75)=..

                    ds_select_dst("1", "7");

                    Any ideas why this is happening?

                    Regards,

                    Matt

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