03-27-2002 01:29 AM - edited 03-01-2019 09:02 PM
Basically I have 2 routers connected via serial leased line using HDLC encapsulation through a CO.
If the serial cable is removed at one end, the other Router still shows the line as up/up.
The 'debug serial interface' command isn't functioning, but I'm sure I've seen this problem on another Router and the keepalives were failing, but the Router still said line was up/up.
I had the idea to add EIGRP across the link, just to get the Routers to send 'hello' messages and to
form a relationship. However this didn't work either, i.e. the serial line is still indicating up/up when the far end cable is removed.
Is this a known IOS bug ?
03-27-2002 01:44 AM
If we experience status is up, line protocol is up too, when no cable is connected too. Then it's possible that
interface needs to be reseated. It may happen with modular devices.
03-29-2002 03:32 AM
I have this problems too but I using the PPP encapsulation with the IOS 12.2. Do you have this experience and why you suggested to be reseated the module ?
03-27-2002 03:55 AM
I should have added that the Router in question is a 1700 series with IOS Version 12.1(3).
03-28-2002 08:45 AM
I am pretty sure that the CO is providing the clocking to both of the routers so if the other side is down, it shouldn't affect the other router. Only on frame-relay if you have a PVC defined from point to point will you see and thing and that will be that the PVC is down.
03-29-2002 05:53 AM
first, be sure that you don't have the command: "no keepalive" in interface config.
i noted this problem in PPP encapsulation too.
but if i wait much enough time, the protocol will finally go down. so i think the problem is proportional to keepalive time. in fact, if i decrease the keepalive time, the time i will waiting for before the protocol goes down, decreases too.
03-29-2002 06:05 AM
So, how long are you waiting? The keep is usually something like 5 seconds, with the hold at something like 15 seconds, I think, for hdlc. The end that loses clock should go down immediately; other than this, you're limited to the dead time.
Russ
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