Cisco 8945 drops calls at first ring

[yogesh.mhatre]

ello All,

We have issue with one of our site having 8945 phones. It only happens with this site. Phone firmware SIP 9-4-2SR3-1.

We have a centralized deployment with many other sites and different model phones.

Randomly, when outbound calls are made internally or externally, sometimes 1 ring on far end phone call drops at calling party phone with phone screen display "phone not registered".

Jan 29 13:38:36, S3, Error, Cisco Call Manager, ccm: 100875: S3.net Jan 29 2021 19:38:36 UTC : %UC_CALLMANAGER-3-EndPointUnregistered: %[Device Name=SEPC4143CB01ABCD][IPAddress=x.x.x.x][Protocol=SIP][Device Type=585][Description=Glen Leary 7231][Reason=6][IPAddrAttributes=0][LastSignalReceived=SIPConnControlInd][CallState=19165697231-call_delivered4][ClusterID=SYS-CL1][NodeID=S3]: An endpoint has unregistered, 1813

On the phone, we performed capture and found phone retransmits the signaling packet (possibly keep alive timeout).

I checked with network team and they have checked and confirmed that there is no network issue. Signaling is marked and don't see any drops.

I also see "481 Subscription does not exist" in packet capture from phone to Call Manager.

Could it be possible that it might be a BUG related?

Any assistance will be helpful?

Regards,

Yogesh

[Nithin Eluvathingal]

[Reason=6]

6: ConnectivityError - Network communication between the device and Unified CM has been interrupted. Possible causes include device power outage, network power outage, network configuration error, network delay, packet drops, and packet corruption. It is also possible to get this error if the Unified CM node is experiencing high CPU usage. Verify that the device is powered up and operating, verify that network connectivity exists between the device and Unified CM, and verify that the CPU utilization is in the safe range (you can monitor this via the CPU Pegging Alert in RTMT).

[yogesh.mhatre]

Hello Nithin,

Thanks. I saw the same and confirm there are no Network issues on LAN or WAN.

I believe that error code is miss guiding towards resolution.

Could this be Bug related?

Thanks,

Yogesh Mhatre

[Nithin Eluvathingal]

Is there a firewall in between ? if yes can you cross check from firewall side too.. 

[yogesh.mhatre]

Thanks.. No Firewall.. its a direct MPLS connection from site to Datacenter. But will check with the Firewall Team if they find anything.

[Scott Leport]

Hi, 

I appreciate it may not be so easy to do this during these times, but I am wondering if you took the 8945 from the problem site to another site, do you experience the same issue? 

Alternatively, if you take a known good working phone of a different model to the site where you have the issues with the 8945 model of phones, do you experience issues with this different model? IMO, that would get a step closer to discovering if it's phone specific or site specific. 

Does it affect internal calls between the same site, this site and a different site or does the issue occur on inbound or outbound calls to the PSTN? 

As for whether or it's a bug, not sure, but I suppose you could also have one 8945 phone upgraded to rule it out.