[SR-Users] Dispatcher algorithm 9 ignores weight=xx attribute

[Alejandro Recarey]

Hi,

I have a kamailio with the dispatcher module setup. I use:

ds_select_dst("1", "9");

to load balance between 3 gateways.

My database looks like this:

id setid destination flags priority attrs

5 1 sip:1.1.1.1 0 0 weight=10
8 1 sip:1.1.1.2 0 0 weight=45
9 1 sip:1.1.1.3 0 0 weight=45

As I understand it, most of the calls should be split evenly between
gateways 8 and 9, and some calls (around 10%) going to gateway 5.

Well, gateway 8 gets 99% of the calls. I am using kamailio 4.1 and I really
cannot understand why this is happening. Running ds_list shows me that all
gateays and weights are correctly parsed into kamailio.

This is the result of my ds_list:

SET:: 1
URI:: sip:1.1.1.1 flags=AP priority=0 attrs=weight=10
URI:: sip:1.1.1.2 flags=AP priority=0 attrs=weight=45
URI:: sip:1.1.1.3 flags=AP priority=0 attrs=weight=45

I have tried changing the priority to 100, or to 1 in every gateway, and
the result is still the same. I have tried adding ; after the weight
parameter, the colon is gone in the ds_list once kamailio parses it.

If, keeping the same database, I use ds_select_dst("1", "0") the calls are
split evenly across all 3 gateways. This is great, but not what I want, but
it at least proves that something is working.

Is there anything else I can try?

Thanks a lot for the help!

Alex

[Daniel-Constantin Mierla]

Hello,

can you add a log message inside c code and send the output at startup?

You have to edit modules/dispatcher/dispach.c

Locate the function:

int dp_init_weights(ds_set_t *dset)

And update the next block:

randomize:
srand(time(0));
for (j=0; j<100; j++)
{
k = j + (rand() % (100-j));
t = (int)dset->wlist[j];
dset->wlist[j] = dset->wlist[k];
dset->wlist[k] = (unsigned int)t;
}

To become:

randomize:
srand(time(0));
for (j=0; j<100; j++)
{
k = j + (rand() % (100-j));
t = (int)dset->wlist[j];
dset->wlist[j] = dset->wlist[k];
dset->wlist[k] = (unsigned int)t;
LM_INFO("weight distribution: wlist[%d]=%u and wlist[%d]=%u\n",
j, dset->wlist[j], k, dset->wlist[k]);
}

Recompile, reinstall and restart kamailio. You should get many log
messages in the syslog starting with 'weight distribution:'. Send them here.

Cheers,
Daniel

Post by Alejandro Recarey
Hi,
ds_select_dst("1", "9");
to load balance between 3 gateways.
id setid destination flags priority attrs
5 1 sip:1.1.1.1 0 0 weight=10
8 1 sip:1.1.1.2 0 0 weight=45
9 1 sip:1.1.1.3 0 0 weight=45
As I understand it, most of the calls should be split evenly between
gateways 8 and 9, and some calls (around 10%) going to gateway 5.
Well, gateway 8 gets 99% of the calls. I am using kamailio 4.1 and I
really cannot understand why this is happening. Running ds_list shows
me that all gateays and weights are correctly parsed into kamailio.
SET:: 1
URI:: sip:1.1.1.1 flags=AP priority=0 attrs=weight=10
URI:: sip:1.1.1.2 flags=AP priority=0 attrs=weight=45
URI:: sip:1.1.1.3 flags=AP priority=0 attrs=weight=45
I have tried changing the priority to 100, or to 1 in every gateway,
and the result is still the same. I have tried adding ; after the
weight parameter, the colon is gone in the ds_list once kamailio
parses it.
If, keeping the same database, I use ds_select_dst("1", "0") the calls
are split evenly across all 3 gateways. This is great, but not what I
want, but it at least proves that something is working.
Is there anything else I can try?
Thanks a lot for the help!
Alex
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