SIP phone not re-registering

Hi

I have a client that has nine sites in the West Indies, with six of them using SDSL connections and the remaining three connected via ADSL. All sites are equipped with an RB951G and two Yealink phones and they all have the same setup.

The local links are a little unstable and it is pretty frequent to suffer small (5 to 10 mins) interruptions in service, with both SDSL and ADSL

With the ADSL linked sites the local IP phones (Yealink) in some instances don’t seem able to re-register : we have to delete their presence from the RB951G connection tracking table in order to enable proper registration
This re-registration issue affects both phones on a site, but rarely both at once i.e. one phone will fail to re-register while the other continues to operate perfectly

The common denominator here seems to be the ADSL

I’m not sure what to test to understand what is going on; I redirected packets from both phones to a remote Wireshark capture
and all I can gather is that, before deleting the connection, the blocked phone keeps sending unanswered registration requests

Any ideas ?
thanks
yann

Two things you can check

  1. make sure you turn off the SIP alg helper: /ip firewall service-port disable sip
  2. On the yealink phones go to “Accounts” then “Advanced” and under Local SIP Port make sure your phones have different ports (5060,5061..etc..)

Number 2 is usually not necessary but lately i’ve had a couple of mikrotiks that for some reason do not let me register and this is the work around for that.

Let me know

Thanks ytuxedo002
The SIP helper is indeed disabled on all the RB951G
I have assigned different local SIP ports and re-registered the phones
will keep you posted
cheers
yann

NB
I came across a post this morning that seems to describe the same symptom we are having
SIP has trouble re-registering when PPPoE links are involved
http://forum.mikrotik.com/t/mikrotik-router-sip-connection-blocked/31641/1

I’m afraid that assigning a different local SIP port provided no improvement whatsoever
I’ll have to settle for a port 5060 connection reset every ten minutes