IP phone registration to core site

[wpetilli]

When IP phones are located in a remote branch LSP and register to a core site what is the protocol used by the phones to keep their registrations?? Are they doing ping and is there a time built in that tells them when to unregister ?

 

[dignoffo]

wpetilli,

H.323 endpoints use H.225 protocol for registration. I am not sure what you asking about regarding an unregister interval.

 

[wpetilli]

We are troubleshooting an issue with phones in India registering to a CM in HK. Random phones are going into discover... what is the full process of phone registration and what keeps the phone registering.. is it sending pings?

 

[bpitt]

Sounds like a network issue between India and Hong Kong. Something is dropping the link. The ip phones should be loaded with the ip address of the call server, the vlan id, and the gateway. If they connect, and then later disconnect and go into discover mode, that tells me that the network connection between the ip phone and the call server is being dropped/failing. Next time it does it, set you laptops ip address as if it was a phone, and try to ping the call server. Do a tracert and see which path it's taking and note the routers between the two sites. Either a router could be failing or a link (carrier) is failing.

 

[wpetilli]

I agree, but if there was a blip the entire office would go discover. Only a random phone or 2 does it so that's what led me to the question about what the phones are actually doing in the background to keep registration. I don't think they would continuously be pinging.. wondering if they do some sort of polling of random intervals depending on when they came up.

 

[wpetilli]

Is there something that can be changed in the phones to not make them as sensitive to go into discover?

 

[latitude12]

The phones send keepalives to maintain their registration. The settings can be adjusted on the first page of the IP network region form. There's more information on the actual mechanisms used in the Network Region Configuration Guide and IP Telephony Implementation Guide.

 

[wpetilli]

Thanks, found this and implemented changes.

 

[smokinjoe2938]

look at the recovery rules for thelsp on page 2, this will tell the phones when to try and reregister back to the core switch

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