Encryption drops causing connections to be re-established

[Joe C.]

Hi - we run mostly encrypted calls using AES on Tandberg equipment. Most of our connections are on ISDN to a Tandberg bridge. During an ISDN call we will loose encryption and have to drop the call to re-establish encryption. This happens quite frequentlly and sometime a few time during a 1 hour call. Anyone know what would cause the encryption to fail so regularly?
cheers
joe

[Sean Lessman]

Hi - we run mostly encrypted calls using AES on Tandberg equipment. Most of our connections are on ISDN to a Tandberg bridge. During an ISDN call we will loose encryption and have to drop the call to re-establish encryption. This happens quite frequentlly and sometime a few time during a 1 hour call. Anyone know what would cause the encryption to fail so regularly?
cheers
joe

I don't think it is encryption failing. Probably something failing within the Bonding routine, maybe the delay between ISDN channels has increased to the point they cannot be synchronized causing the downspeeding mechanisms to kick in. If the channels cannot be synced back up again due to flaky network, the call will drop or may have to be dropped by you and re-established. When this happens, the first thing that goes is encryption.

Just a thought. Only way to figure this out is to work with the support people at TANDBERG and to take a few logs.

Sean

[nomad]

Sean,

On a similar thread I got this message: "Encryption could not be verified" when a call dropped, is this bonding?

[11B-33T]

On a similar thread I got this message: "Encryption could not be verified" when a call dropped, is this bonding?

Are you calling H.323 or H.320 to the other endpoint?

I'd say no, it's not a bonding issue. The call has been established and your codec is attempting to sync its encryption algorithum (either AES or DES) to another codec whose security features may not be enabled.

We just tested a TB 6K MXP (SW F7.0) w/Encryption set to on, Encryption Mode set on auto, with a TB 25K (SW E5.3) and Polycom VSX 8K (SW 8.7.1) both with encryption set to off. Calls were placed to/from the 6K MXP @384k via IP & ISDN networks and the calls were fully bonded yet both non-encrypted codecs would display a TB message stating encryption needed to be intiated before the conference would continue. After 2-3 minutes an audio warning would alert us taht the conference call is dropping and disconnect the session.

I did not observe a message of "Encryption could not be verified" when a call dropped however...

[nomad]

H.323 internal call between US and UK, call was running for 15 minutes or so before it dropped...

[Sean Lessman]

H.323 internal call between US and UK, call was running for 15 minutes or so before it dropped...

I haven't seen that. If its H.323, Bonding does not apply. Was the message a banner on the bottom of the screen (codec generated) or a full screen picture (MCU generated)?

Sean

[nomad]

Hi,

Was hosted on a Codian MCU, I never saw the error message so not sure. I'll do an Xhistory next time, but never heard of that error before.