Serial line bouncing - keepalive time mismatch

[scjslcc]

I have a serial line that bounces periodically. I've had the carrier test it extensively with no problems found. Today I turned on "debug serial interface" and I see the the hdlc keepalive sequence messages. I'll see the interface miss 3 keepalives and then reset itself. At this time I also see a message "Keepalive time mismatch - should be 10 secs, is X" where X can be any number. I've tried adjusted the keepalive's on each router to different numbers but this hasn't improved the situation. Any ideas on what else to try or where I can find info about the keepalive message?

[steven-dunn]

if you have got a missmatch in default settings for HDLC and can't figure it out, try PPP or frame-relay encapsulation and hope the defaults match.

[vincent-n]

How about doing this:

1. Save the configuration and edit the serial interface to take out any keepalive settings.

2. Clear the router's config and reboot the router to factory settings.

3. Paste the config back and turn on debug serial interface.

4. If still not work then try changing encapsulation method to say PPP or FR (as recommended by previous post) and then change back to HDLC. By the book, when you change back to HDLC, the router should clear any previous HDLC settings.

Godd luck and let me know how you go.

[sainatara]

I tried PPP and changed back to HDLC still same issue persist(serial interface flapping/line protocol down)

[Richard Burts]

You picked an old discussion to join with your issue. But we will try to find a solution for your issue. As a start would you tell us what type of devices are connected on this serial link, would you post the output of show interface for the serial interface on both devices. If that does not show the problem we would want to see the configuration from both devices. So you might as well include the configurations in your post.