lab troubleshooting

I just started with a real lab and i need some troubleshooting tips. I've got 2 2612s.

When i use routerA as my DCE, the line protocol status toggles up/down about every 30 seconds or so. When I switch the cable around and configure RouterB for clocking there is no problem.

any thoughts on what could be wrong?

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Comments

Alien

Under normal circumstances the DCE cable is usually connected to interface serial 0 and the DTE cable is connected to interface serial 1. Sometimes they can be interchanged but the interface connected to DCE must be assigned a clock rate setting to enable it provide clocking and signalling. Could it be that you are connecting the DCE connector to RouterA's serial 1 interface? Have you assigned the clock rate to interface connected to the DCE?

Drakonblayde

Honestly, on 2600's it doesn't matter... I've routinely connected s0 to s0 and s1 to s1 with no problems. As long as one is set for clocking, it's all good (I tend to set both ends for clocking just so I don't have to actually pay attention to which cable is which... the DTE end will just ignore the clock rate command)

Shuffles, switch the wics in your routers. If the same card produces the same effect in the other router when you set it to clock, it's a bad WIC

tunerX

You can have several problems.

1) You have a bad cable.

2) You have the wrong cable (RS-232 should only clock to 128000; clocking the cable higher will cause those symptoms).

3) You have a bad serial interface.

4) You do not have the same encapsulation.

5) your cables are not really DCE/DTE (do a show controllers and verify that one of them senses DCE and the other end senses DTE with TX/RX clocks received).

Alien

Wow, TunerX has surely put his immense knowledge here. I couldn't think of all those physical layer possibilities before. By the way those certs are PHAT to say the least. I wonder when i'll ever get there.

Cheers!

Drakonblayde

If it works one way and not the other way, it's probably not the cable though. If I had to guess, I'd say he's probably using WIC-1T's or WIC-2T's, and if it's WIC-2T's, I wouldn't be the least bit surprised if one of them were bad, seen more than a few. If it works one way and swapping the cables and configuring clocking on the new DCE interface is all that's going on, it's probably not encapsulation either.

So if I had to guess, I'd say probably a bad interface, but you can't ever discount a configuration error hehehe

Like I said though, easiest way to see if it's a bad card is to swap them around in the routers and see if they still do the same thing (it could also be something as simple as a card not seated properly, seen several act funky because of that). If so, then chances are better than even that he's got a bad (and if he got it off ebay cheap, probably counterfeit) WIC

shuffles62

thanks for the replies. i'll try swapping the cards when i get home tonight.

-if the cable were bad or the wrong one, how would it work when reversed? the cable actually says DCE & DTE on each end. I set the clock rate on the end that says DCE, but i'll do a sh controller tonight as well to verify.

-encapsulation is definitely set to hdlc on both sides.

I guess the signs are pointing towards a bad serial card, the one that is supposed to be providing the clocking, i assume.

I bought it all as a kit from ciscokits.com. The chassis are definitely used, but the serial cards look new. I'd be pretty pissed if they turned out to be counterfeit....is there any way to verify?

tunerX

I didn't catch the second part of your post that said the problem was corrected when you flip-flopped the cable.

From what you described, your cable is a standard V.35 crossover so you should be able to clock it at 8MB without any timing slips.

I have some MC3810s that when you enable the DVM module you cannot provide clock out of the S1 interface but you have modular bays so you should not have this problem.

Fu Loser

I cant remember this one right....

Doesnt it matter what type of encapsulation he is using? I thought on some encapsulation types clocking doesnt actually effect the transmission speed of an interface, its only used as a variable in some routing protocols?

Or was this only when connectiong to T1's??

I could be way off here, I dont really remember.

Hope you can get the problem solve soon buddy!

Drakonblayde

Fu Loser wrote:

I cant remember this one right....

Doesnt it matter what type of encapsulation he is using? I thought on some encapsulation types clocking doesnt actually effect the transmission speed of an interface, its only used as a variable in some routing protocols?

Or was this only when connectiong to T1's??

I could be way off here, I dont really remember.

Hope you can get the problem solve soon buddy!

Well, yes, encapsulation matters, but he said after he flipped the cable, it worked, which means that encapsulation isn't his problem, they're both running the same thing.

shuffles62 wrote:

I bought it all as a kit from ciscokits.com. The chassis are definitely used, but the serial cards look new. I'd be pretty pissed if they turned out to be counterfeit....is there any way to verify?

Well, if you can post a picture of the cards, I can probably tell you whether or not they're fake. Anyone who deals with mass quantities of cisco equipment quickly learns to pick out the good stuff from the bad stuff, and I would hope ciscokits would know the difference and not knowingly ship fake stuff, so it's possible that the card is just faulty. And again, like I said, it may be something as simple as the card not seated properly.

Now what'll be real interesting is if it works alright in the other router. If that's the case, then it's possible somethings up with the wic slot on the router, or maybe the contacts aren't clean, or some other pain in the rear problem.

Fu Loser

< Duh

THanks for the quarity

shuffles62

looks like the problem is within the wic.

now i'm torn. i was planning to take the ccna on 5/28 so i don't want to lose study time by sending it back right now. i can get everything up and running as long as wicA isn't the dce, but i'm just worried that this is going to be a sign of more problems down the road.

Drakonblayde

shuffles62 wrote:

looks like the problem is within the wic.

now i'm torn. i was planning to take the ccna on 5/28 so i don't want to lose study time by sending it back right now. i can get everything up and running as long as wicA isn't the dce, but i'm just worried that this is going to be a sign of more problems down the road.

Well, honestly, if you were planning on taking it that soon, I'd just go ahead and do your studying and prepping if it's behaving alright as the DTE. Then I'd seek a replacement after you took the CCNA.

Which WIC is it, out of curiosity?

shuffles62

its a wic-1t