IP phones don't ring

[FinaMorten]

We have two problems with our newly installed IP phone system with MD110 BC13 sp2 with IP phones dialog 4422IP.
Sometimes the receiver phone (IP) don't ring at all, but the caller hears ring tones. They have to hang up and try once more. Then the call gets through. This happens often, but I have not found any pattern yet.
The second problem is that sometime the caller gets an error in the display saying "Overbelastning" (We have a Norwegian system), this means something like "Overload".

So far our Vendor has tried to
* reset the board
* reset the hole MD
* Updated the phone software to the newest version R4F
* Changed the config file parameter RRQTtl from 600 to 290 to make it lower than the mac ttl value on our switch.

All ideas will be appreciated.

 

[whosrdaddy]

seems like a network problem to me.
anyway latest servicepack is SP3
you are using IPLU, what firmware revision? (CNBIP:BRDID=119,LIM=ALL)

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What You See Is What You Get
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[FinaMorten]

I think the next step from our vendor is planned to be an upgrade to SP3.
CNBIP generated :

002-1-00 IPLU
ROF1375067/2 R1A
CAA 158 0040 R2G EXE APPL
CAA 158 0037 R1B EXE KERNEL
CAA 158 0038 R1D EXE ROOTFS
CAA 158 0039 R1F EXE MSP
CAA 158 0046 R1A EXE INITRD
RYS 102 770 R1A EXE BOOT
RYS 102 777 R2B EXE FPGA
PCB CODE 2 EXE HW CODE 0
Wed Sep 20 2006 EXE 17:03:29

 

[whosrdaddy]

ok,
make sure that IPLU is R3A after the upgrade to SP3.
if the problem persists, the vendor will need to make ethereal LAN traces to see what's the problem...

-----------------------------------------------------
What You See Is What You Get
Never underestimate tha powah of tha google!

 

[FinaMorten]

OK, thanks for the tips so far.

I will check after the upgrade.

 

[FinaMorten]

Now, everything have been upgraded to the latest version. The problems are still there.

We have noticed that if we run a script that pings directly to the phones every 30 sec., the problem seems to go away. So I believe that there is something to do with a timeout of a session somewhere.

 

[himdp]

Could be this -

Security setup on the net-work switches


There is an "aging" timer in the switch which determines when a certain MAC address is unloaded from a table, and sofar becomes unvalid after a certain time without traffic.
In that case the switch will not accept traffic towards this terminal, until the terminal itself has updated the table again with active traffic (e.g RRQ).
After that the traffic in both directions is accepted again.
To avoid this "aging time out", the RRQ time in the IPPhones config file should be shorter than the aging time in the switch. Observe that we have terminals or applications(SEC) with FIXED RRQ times, in this case the switch parameter has to be adjusted.

 

[FinaMorten]

Yes, this is what We also thought could be the problem. Early in this case we changed the variable RRQTL in the config file to be 290 instead of 600. But it could be that we compared with the wrong variable in the switch.

Do you know which variables/settings in our switch that we should look into?

We have a Cisco WS-C3560-48PS-S as a end switch and a Cisco WS-C3750G-24TS as core switch.

I also figured that, since it helps to just do PING to keep the connection alive, the problem exists in the lower part of the OSI model.