Re: Dispatcher Probing issues

Hello,

try to set ds_timer_mode to 1 to use a dedicated timer for that many destinations and really short probing frequency.

If you are using ds_probing_mode 1 it should continue to probe even when there is a failure.

I don’t fully understand the reason behind using the tm event routes for this job. There are dispatcher event routes, and you can just query the dispatcher destination UP/DOWN status in the script as well with ds_is_active.

Cheers,

Henning

From: Sergio Charrua via sr-users <[email protected]>
Sent: Mittwoch, 11. März 2026 13:55
To: Kamailio (SER) - Users Mailing List <[email protected]>
Cc: Sergio Charrua <[email protected]>
Subject: [SR-Users] Dispatcher Probing issues

Hi all,

I'm having issues to get the dispatcher probing settings right.
the requirements are:
- when Kamailio starts, it needs to probe all endpoints to check availablility (nearly 5000 endpoints, in total) by probing each one of them, sending SIP OPTIONS every ds_ping_interval=5
- when receiving a valid reply (ds_ping_reply_codes set toclass=2), and after ds_inactive_threshold=2, Kamailio should send an EVAPI message to inform endpoint is UP
- htable gw_last is reset with key=IP:PORT of endpoint, value = timestamp)
- htable gw_probe is reset with key=IP:PORT of endpoint, value = 0 (NOT PROBING)

- when receiving an invalid reply or timeout, and after ds_probing_threshold=3, Kamailio should send an EVAPI message to inform endpoint is DOWN
- htable gw_last is reset (key=IP:PORT of endpoint , value = $null) and htable gw_probe reset with key=IP:PORT value = 1 (PROBING)

- an htable gw_last with autoexpire=60s will launch a probe to the endpoint set in the key of gw_last (key=IP:PORT , value = timestamp).
Once probing, it should send an EVAPI message with the endpoint's status (UP or DOWN) respecting the ds_inactive_threshold and ds_probing_threshold parameters.
- and htable gw_probe with key=IP:PORT is updated to 1
- probing is started by updating dispatcher's endpoint status using:
jsonrpc_exec('{"jsonrpc":"2.0","method":"dispatcher.set_state", "params" : ["ip", 1,  "' + $var(endpointIPPort) + '" ]  }');

- I have events like dispatcher:dst-up and dispatcher:dst-down, where it resets gw_last and sets gw_probe to respective values, depending on probing response.

My issues:
- Kamailio is starting with all endpoints set as FLAGS=IP and starts probing all endpoints
- if endpoint fails replying to SIP Options, because it is offline, and there is a TIMEOUT, it will be set with FLAGS=IX *AND* Probing stops without any instructions from my script; AND dispatcher:dst-down is never called
- if endpoint replies OK to SIP Options, dispatcher:dst-up is not called neither so I cannot reset gw_probe and gw_last values.
- I have event_route[tm:local-request] who detects the sending of the SIP OPTIONS and implements t_on_reply("PROBE_REPLY") and t_on_failure("PROBE_FAILURE").
if SIP Options receives a reply, endpoint is UP, t_on_reply("PROBE_REPLY") is launched as expected; if SIP Options fails,  t_on_failure("PROBE_FAILURE") is not called.
- when the gw_last expires (every 60s) and starts Probing the endpoint, it is never on 60s but always after 70s of last probe period, and in time it increases up to 85s. Why??
- SIP OPTIONS retransmissions are indeed correct: 0.5s + 1s + 2s + 4s then timeout (as per TM fr_timer=10000 setting)

Questions:
- what dispatcher settings should I use to achieve my goal? I have been playing with ds_probing_mode and with dispatcher's list FLAGS value, but no results so far....
- any solution?

NOTES:
- dispatcher is only used for probing, not failover or call distribution

Current Dispatcher definitions:
    modparam("dispatcher", "db_url",                        "cluster://k1")
    modparam("dispatcher", "ds_ping_interval",              5)
    modparam("dispatcher", "ds_ping_method",                "OPTIONS")
    modparam("dispatcher", "ds_ping_from",                  "sip:[email protected]<mailto:sip%[email protected]>")
    modparam("dispatcher", "ds_probing_threshold",          3)
    modparam("dispatcher", "ds_inactive_threshold",         2)
    modparam("dispatcher", "ds_ping_latency_stats",         1)
    modparam("dispatcher", "ds_probing_mode",               0)
    modparam("dispatcher", "ds_latency_estimator_alpha",    200)
    modparam("dispatcher", "reload_delta",                  0)
    modparam("dispatcher", "flags",                         0)
    modparam("dispatcher", "ds_ping_reply_codes",           "class=2")
    modparam("dispatcher", "xavp_dst",                      "DISPATCHER_DST")
    modparam("dispatcher", "ds_timer_mode",                 0)

Current TM definitions:
    modparam("tm", "auto_inv_100",               1)
     modparam("tm", "failure_reply_mode",        3)
    modparam("tm", "fr_timer",                  10000)
    modparam("tm", "fr_inv_timer",              120000
    modparam("tm", "max_inv_lifetime",          180000
    modparam("tm", "max_noninv_lifetime",       32000)
    modparam("tm", "retr_timer1",               500)
    modparam("tm", "retr_timer2",               4000)
    modparam("tm", "wt_timer",                  5000)
    modparam("tm", "cancel_b_method",           2)

Current Dispatcher list:
+----+-------+--------------------+-------+----------+----------------+-------------+
| id | setid | destination        | flags | priority | attrs          | description |
+----+-------+--------------------+-------+----------+----------------+-------------+
|  4 |     1 | sip:10.20.0.6:5060<http://10.20.0.6:5060> |     9 |        1 | cc=1;duid=sbc1 |             |
+----+-------+--------------------+-------+----------+----------------+-------------+

Atenciosamente / Kind Regards / Cordialement / Un saludo,



Sérgio Charrua

www.kahea.ai<http://www.kahea.ai> / www.voip.pt<http://www.voip.pt>

OpenTelecom - Consulting for Telecoms, Lda
Tel.: +351 <callto:+351+91+104+12+66> 91 631 11 44

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