Frame Relay Hardware and Cabling Question 1

[sk391]

Hi guys,
I have a question about the hardware and phyical connections needed to setup a frame relay network. I have the following routers and need to get them setup for frame relaying for CCNA studying. I dont really want people to give me the commands because I want to learn by doing, but can someone please let me know how I would go about cabling this up... or even if it is possible.

I have the following..

2 * 2503 routers both with two serial interface slots, 1 AUX , 1 * AUI, 1 * bri

1* 2801 router with 1 serial interface card and 2 * fa ports 1 * aux port

Is it possible???

Thanks

 

[nelsonrherron]

I have to set the clock on the host interface because my cabling can't be swapped - smart cable vs db60/WIC2T vs WIC1T. I've run out of pieces. The DCE cable will only fit the host adapter. I thought the physical DCE and the FR DCE had to overlay. Was it as simple as making the FR lmi-type dce on the FR switch (L2) and specifying a clock rate on the host interface (L1)? If so, you are absolutely right - I confused a couple of pretty simple ideas. If not, I give.

 

[jneiberger]

The FR DCE is not related in any way to the physical DCE. The frame relay switch must be the DCE. The router interface with the DCE cable must be the physical DCE providing clocking to the link.

 

[jneiberger]

I should rephrase. The frame relay switch must be the *FR* DCE. It can be the physical DCE, but that's a function of which end of the cable is connected to the box.

In a case like this, you have two different concepts using similar terminology. You have a layer one DCE/DTE based on the cabling, and then you have a layer two DCE/DTE based on signaling types and layer two protocols. They are completely unrelated.

 

[nelsonrherron]

John:

Very good. I like that explanation. It clarifies many things that I had never seen properly written out and sure makes troubleshooting FR make more sense. I had never really been in a position to think about it much for several years. Nobody I knew had either. The standard configs in the books/sites all have FR DCE and phy DCE on the same if so the issue isn't very obvious.

It was just the vagaries of various if cards and chassis's not working together in my junkpile of spares. My old FR switch blew its gaskets a couple of days ago and the assorted incompatabilities caused me to have to wire my fifth and sixth ifs up backwards.

Many thanks again. It was a good learning project for me and you got a co-worker into my lab with his six FR-connection scenarios accessible. When I was a kid there used to be comic that had some by-line like "A tip of the Hatlo hat" when he used somebody else's suggestion. In this case it's a tip of the Herron hat.

 

[burtsbees]

Huh???

Anyway, you may want to try a back-to-back frame lab, without the frame switch. Just a thought---works...

Burt

 

[nelsonrherron]

Burt:

Sorry, six FR links required in all. This is a regular CCIE lab set that I was requested to boost from four to six to accommodate some different scenarios. During the fussing the frame switch rolled over. My old faithful 7500/PA8 is out on loan, but probably draws too much power for a frame switch. The 2600s and 3600s (esp. 3620s) appear to have some NM/WIC incompatibilities. All the pieces have worked recently in different individual capacities but together they failed. The NMs would not show up in the running configs as unconfigured devices when I inserted them although they might appear erratically in the show ver. That led me to the problem I presented and John's observation that FR and phy DCEs are entirely different, a situation I either never knew or forgot so completely I don't know that I ever knew. In any event back-to-back is out in this situation.

 

[burtsbees]

The NMs would not show up in the running configs as unconfigured devices when I inserted them although they might appear erratically in the show ver.

Sounds like an IOS issue. NM modules should work together, especiall between 1700's, 2600's and 3600's. What exactly do you have? Give us a list---we can give you some really great lab suggestions, guaranteed. If Cluebird comes in to this thread, he's an instructor for NA and NP, so he may offer some suggestions, as he is working on the lab portion as well (he has passed the written). I will not be ready for a while---not much experience in the past 2 years of being a CCNP...

Burt

 

[nelsonrherron]

Burt:

E-mail at nelsonrherron[at]sbcglobal.net & I'll explain why I don't want to chase it further. Best not to carry this further in the forum.

Nelson