HDLC debug output not available after IOS 15.7 upgrade

[michael.j.murphy3]

I recently upgraded my 2951 Router from IOS 15.4 to 15.7.  Before the upgrade, I woud type

debug serial int

to get the HDLC debug output

and I would get the following debug output

HDLC myseq 6, mineseen 6*, yourseen 7, line up

Now, after the upgrade, I can't get those debug messages anymore.  Any ideas?

[Georg Pauwen]

Hello,

is it possible that the default encapsulation on serial interfaces has changed from HDLC to PPP in that release ?

[michael.j.murphy3 · Accepted solution]

It wasn't a problem, specifically, with the debugging system.



It turns out, that in upgrading to the newer version of the firmware, the ignore-dcd setting became unset at some point. I need to ignore that signal, because there is inline crypto that brings the interface down until it has re-synchronized with it's peer. Once I set that to true, the keepalive messages began to run continuously as expected.



Thanks.