Not able to communicate with remote IP phones

[SwathyEdayath]

Dear Team,

We have one remote site with three phones connected via VPN from main site. the phones are having same configuration as in main site .

we are able to make outgoing calls from these phones both internal and PSTN . but we are unable to reach these phones dialing extension and direct line as well . even the phones are not mutually reachable . please suggest .

Regards

swathy

[SwathyEdayath]

Dear Team,

We have been following up with network and firewall team. They said they can see phone sending Reset request instead of packets .PFA logs provided by them .still issue is unresolved.

[Manish Gogna]

There are no logs attached, again to see why the phone is sending a Reset request we need the entire sequence of packets that lead to the phone sending such a request, getting the captures from either CUCM or IP phone is required. How do we know that all the traffic from CUCM is reaching IP phone or vice versa? This troubleshooting can go on forever if the correct info is not captured, you can engage TAC to get their perspective as well.

Manish

[SwathyEdayath]

Hi Manish,

sorry for delay in replying, we had holidays last week .We do not have direct contract with cisco ,hence I couldn't check with them .The issue seems to be very rare , as a 6901 phone recieves calls without any trouble . problem with other advanced models ,i.e. 7821,8865 etc. what i understood is 6901 is only sccp here other phones are sip .

[SwathyEdayath]

Hi, Finally it has given a temporary solution . The problem was that TCP three way hand shake not happening . Hence the communication problem . Created a new phone security profile with transport type only as UDP , which resolved the issue.

[HARIS_HUSSAIN]

Good to know that issue is resolved.

[Mohammed al Baqari]

Good news. Please remember to rate useful posts

[Manish Gogna]

Check the Route Plan report to see if there are any Unassigned DN's or overlapping patterns which are same as the extensions of these phones. You may try changing the extension of one of these 3 phones to a completely new series like 4444 instead of 2222.

Manish

[SwathyEdayath]

Hi Manish , I did the same . assigned a fresh extension number to one of the phones , but no luck .

yesterday there were no audio on IP phone's side for PSTN calls .the other end can hear . later I added IP route to the new network in gateway and issue resolved . our network is 192.168.7.X and the remote site is in 172.21.20.X .

[Manish Gogna]

CUCM is responding with a 100 trying and 503 Serv Unavailable immediately after getting the Invite w/SDP , this error would point to an issue on the server side. Can you try registering these phones with a different callmanager server or try restarting the callmanager service on this one.

Manish

[SwathyEdayath]

Hi Manish,

Tried the same . Registered phones with primary CUCM but no luck . I have restarted call manager service on both servers , but still didn't work.

[Manish Gogna]

I would suggest opening a TAC SR in that case.

Manish