ip phone registration remote sites

[jack samuel]

Dears,

i have an issue for the phones registration on remote site, i have a CUCM in HQ and remote sites are registering on HQ CUCM, the link between the HQ and remote sites is 1 MB, i have 9971,8945,7841,3905 phone models, once the bandwidth is consumed high on the link most of the time 3905 phone deregisters first and then the other phone models and when the consumption on the link decreases all phone registers again except the 3905.

why that so is it 3905 phones has very less timers for the keepalive or some other technical stuff to understand??

also i want to justify to customer the problem is not with the cucm but with the bandwidth between the sites.

thanks 

[Chris Deren]

I think you are asking the wrong question, rather focusing on re-registration timing (could be bug, etc) you should ask why phones are unregistering and how to avoid. Typically phones are more important that other local apps and for that reason you prioritize their traffic on the network, if that is your desire then you need to make sure your signaling traffic (SIP, SCCP) gets adequate bucket in your QoS policy over the WAN to avoid issues like these.

[jack samuel]

Dear chris,

thank for the reply,

Have already informed the customer according to your suggestion as to reserve bandwidth for signalling but i want to make sure and justify from my end to the customer,

so i want to know the traces that i need to collect from the cucm for justifying the problem is not from my end but from the ISP end.

Thanks

[Wilson Samuel]

Years ago I have had a similar situation with a customer whose phone re-register on occasion.

After few testing we found that the WAN Link was flapping :-(

So I would want to see if there is any inconsistencies in their link like higher packet drop rates, or congestion etc.

What is the kind of WAN interface they are using at the remote sites?

HTH

Plz rate all helpful posts.

[Dennis Mink]

First of all, I am with Chris on this one, use QoS to allow signalling traffic, its not a lot of traffic, so you should be able to slot it in even though you have 1Mbps.

As far as I know, station keepalives are set to 30 seconds for primary and 60 for secondary server. this is enterprise wide. So I am not sure why you are seeing differences between phone types.

Are all phones on SIP or are some on SCCP?