[OpenSIPS-Users] dispatcher problem

Fri Feb 3 01:59:14 CET 2012

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.12DBG: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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