We are trying to push an image on 400 phones using the Phone.Push Method in CiscoSDK and we receive <CiscoIPPhoneError Number="6" /> on random phones.
the error occurs when trying to push to this huge number of phones, but doesn't occur when sending to few number of phones.
Can you please advise what's the reason of this issue?
Inspecting a network packet capture of the application traffic (e.g. via Wireshark) may be helpful. Feel free to attach here if you do not spot anything...
Thanks a lot for your reply.
Attached the Wire Shark Capture.
Error Number 6 indicates a timeout problem. I'm seeing TCP Window Full and TCP Zerowindow errors in the pcap (this happens when the TCP receiver cannot accept any more data), which may be related to your problem. Are the phones all the same? What type of phones, and what's the firmware version?
More information: The errors seem to be tied to the IP address 10.112.160.56.
The IP Address 10.112.160.56 is the IP of the server where the application is running on.
The phones are different, below are the models and their firmware:
Cisco 9971 sip9971.9-4-1-9
Cisco 7975 SCCP75.9-3-1SR4-1S
Cisco 7941 SCCP41.9-3-1SR4-1S
Cisco 7961 SCCP41.9-3-1SR4-1S
Can you tell us where this packet capture was taken? I suspect it is from the application server host..?
A typical error scenario looks like the below:
POST /CGI/Execute HTTP/1.1
HTTP/1.1 200 OK
<CiscoIPPhoneError Number="6" />
As there is >2 seconds between request and response, I would also suspect that the phone is timing out trying to establish a connection with the page it is supposed to retrieve (or possibly the Authorization URL.) As the retrieve URL seems to be the same host as the requestor - and per Nick's observation the app host network connection may be experiencing congestion - this may indicate that the server is overwhelmed and is unable to serve the page quickly enough, causing the phone to time out.
If you can manage to obtain a pcap from a phone (e.g. by plugging in a PC to the phone's extra switch port), this would give a clearer picture of what's happening at the phone during this 2 seconds. My expectation would be we would see the phone attempting to establish TCP connections and timing out. If not (for example if the phone appears to do nothing for 2 seconds and just returns the error) we may need to look at the onboard phone logs to see what's happening...
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