Files downloaded by cisco phones from TFTP server

Nadav · ‎02-07-2016

Hi everyone,

I'd appreciate clarification regarding the files being downloaded by phones in my lab from the CUCM TFTP server. I've read online only partial explanations of the files being downloaded, and some of the files which my phones are downloading don't appear in any of these papers (as far as I can tell).

These files are:

1) CTLSEP<MAC>.tlv

2) ITLSEP<MAC>.tlv

3) SEP<MAC>.cnf.xml.sgn

4) tzupdater.jar.sgn

5) DR....xml

6) SK.....xml

Why would the phone download the CTL file? Shouldn't it be installed once from a secure segment?

Why would it bother to ask for an ITL file if a CTL file is available?

Is it acceptable that timezone files are downloaded to phones rather than being dependent on the firmware version of the phone?

What are these DR and SK xmls? I can't find any reference to them online.

Thank you very much for you time!

Nadav · ‎02-07-2016

Short update,

After some fishing, DR are dialplan files and SK are softkey templates. My other questions are still viable though :)

By the way, after checking out the download times for the different files it seems that the tzupdater.jar file is the largest by orders of magnitude (nearly 600 blocks of TFTP). Is there any way to ensure that 79xx and 78xx phones won't download these files? TFTP over high-latency connections may suffer several minutes of boot time due to downloading tzupdater.jar and timezone configurations usually change only once every few years.

Rajan · ‎02-07-2016

Hi Hod,

TFTP servers will provide CTL file to phone only when the cluster is in secure mode but the phones while booting up will request for both CTL and ITL by default but gets it only when the cluster is secure. Even though the phone has CTL file, it will request for iTL starting with CUCM version 8.x with the introduction of SBD feature.

The below document by Jason clarifies more on CTL, ITL and SBD very well.

https://supportforums.cisco.com/document/68701/communications-manager-security-default-and-itl-operation-and-troubleshooting

HTH

Rajan