I’ve got a problem with phones failing to register on the system that have previously been OK. A setting on the phone has been used in an attempt to keep alive the registration but this hasn’t resolved the issue. There is a setting in Phone Configuration for Monitor / Keepalive Override but I can’t find any information on this option and can’t see it in Global settings.
Can anyone let me know what this does or if they’ve resolved the failing to register on one or more accounts on a phone ?
I’m still working on this issue and would appreciate any assistance from anyone who has resolved this type of issue in the past.
The monitor / keepalive override I was asking about can be found by navigating to:
System
Phone Hardware
Select a physical phone
Monitor / Keepalive override
Drop down options “Use system default” “Disable” or “Enable”
I think I’ve found where the system default is set :
System
Global
Network
Advanced
Default for monitor phones “false/off”
The tick box is unchecked
We implemented a work around on our Yealink T22P phones by
manually setting keep alive on each account available on the phone. However when all phones were rebooted from the pabx the configuration was gone. The only phones that weren’t altered were those that were powered off when the reboot
occurred. When these phones were powered on the keep alive setting was retained.
How can I get the configuration file that must be sent from the pabx to the phones to have the keep alive setting as part of its image ?
Hi Dave,
Just noticed this thread, and sorry it looks like you haven’t got a reply. Maybe you have been working with your reseller which is always the best way to get a fairly complex connectivity related issue like this resolved as they will hopefully know a bit about your network topology and me able to advise on more specifics.
Both of the keepalive/monitor options on the PBX appliance (global, or per phone) simply turn on monitor probes for the affected handsets. This causes us to send a SIP OPTIONS ping from the appliance to the device on an adaptive basis. We expect to get back either an OPTIONS response or even just a 404 (SIP devices that don’t understand OPTIONS should and generally do send a 404 response which is perfectly good enough to indicate that it is there).
Using monitor/keepalive is a great way to detect intermittent connectivity issues as you will then get log entries when a device doesn’t respond (UNAVAILABLE) or takes a long time to respond (LAGGED). As a side effect, it can also affect some kinds of network errors relating to one way firewall state timing out, as the periodic monitor probes in effect can keep some state alive even if your firewall is not configured to pass packets correctly and therefore cause things to work (for a while) that are otherwise broken. We wouldn’t recommend however that you use keepalives as a sticking-plaster for firewall configuration changes for a few reasons I can think of:
Even if they help the symptoms therefore, they are unlikely to be a complete solution as devices will still be able to “stick” in an unregistered state in some circumstances.
The best way to resolve this is to examine the packet filtering rules on any devices between the phones and appliance and/or trace the SIP packets on the network to determine where/how they are being dropped or mangled (e.g. SIP ALG enabled?) and then resolve that. Turning on phone monitor to keep track of any phone drop outs can then help work out if you still have a problem.
Let us know how you get on.
Rob
Thanks for the comprehensive reply, it’s more than we’ve had from other sources, I always treated the keep alive as a workaround and not a long term solution, hopefully this will be fixed properly.
Dave
Rob
As well as retaining the keep alive setting on the PABX we’ve now increased the timeout on the firewall, hope this is the end of the issue. Thanks for your help.
Dave
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