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Community Member

Urgent Frame Relay Question

I know I'm showing my inexperience here, but I desperately need help. =) Installing a new 3745 router at our corporate office. I was unable to 'preconfigure' as I needed to remove WICs from existing router (3640) to add to new router so that I could configure it.

Here's the problem, copied and pasted config into new router - connected and booted it up - everything looked greatu up until I tried to bring up all of the interfaces. Frame-Relay will not come up.

I was doing research and there was a note stating that when using subinterfaces for FR, they must be configured and brought up before their serial interface is brought up. That if the serial interface was brought up before the subinterfaces, it could screw up the Inverse ARP, preventing connection?

This is our main router (internally), I have to bring down all of our branches (and automated teller machines!) to replace it - so if this is definitely not my issue, I need to do more research before attempting again.

P.S. When I put the 3640 back together and booted it, FR came right up, so I know it's me - not them. =)

Thanks in advance for the assistance!

Community Member

Re: Urgent Frame Relay Question

I've haven't encountered a situation where the sub-interface had to be configured before the physical interface was operational. In fact, I'm frequently adding new sub-interfaces to existing ports as the telco provisions new PVC's.

A couple of things that do come to mind are:

This is something that I have overlooked in the past. When copying a configuration from one router to another, the "no shutdown" command on the interfaces isn't present in the configuration that is pasted into the new router. After pasting in the configuration, you will still need to issue a "no shutdown" command on the serial interface and any other inteface that you need operational.

There's also another issue that I've encountered when copying and pasting in a large configuration all at once. With a 9600 connection, the transfer rate is slow enough that many terminal programs are unable to buffer the entire configuration. The result is that the router receives an incomplete or corrupted configuration. The solution is to use multiple copy and paste operations or to assign an IP to the device and then tftp the configuration.

Lastly, when you populated the slots on the 3745 with the WIC's did the interface designation for the serial interface stay the same as it had been on the 3640? If the interface was s0/0 on the 3640, is it s0/0 on the 3745. If not, before pasting the configuration into the 3745, it will need to be modified to reflect the differences.

Community Member

Re: Urgent Frame Relay Question

Well, this is certainly disappointing. =)

In answer to your suggestions: When I boot the router, I bring the interfaces up with the no shutdown command. Transfer rate - I double-checked the config against the text file I was working with - everything matched. Finally, the interface designations did change, I updated the changes on my text config before I pasted to the new router.

So, the upside is that I did all the easy to miss stuff... The downside, my FR won't come up... It's just weird - everything looks like it should work - the config (interface designations not withstanding) matches the old router exactly. It's almost as though I need to find the "on" switch to make it talk.

Thanks for your assistance!! I appreciate your attempt to help!


Community Member

Re: Urgent Frame Relay Question

Like you said, so much for the simple things. If you have resolved the issue, you might want to:

- if you have an internal csu/dsu, verify that layer 1 is active by using the "show service-module t1" command

- check on the number of lmi enquiries sent and recieved "show frame lmi". The should be incrementing pretty much in lock step with each other. If not, is the lmi type set correctly?

- check on the pvc status using "show frame pvc". the dlci's usage should be local, the status active and are the dlci's associated with the appropriate sub-interface.

failing all that, there's a troubleshooting guide at <>


Community Member

Re: Urgent Frame Relay Question

Thanks for the tips!

And no, the situation has not yet been resolved. The next attempt has been rescheduled until next week. I'll keep you posted either way. Keep your fingers crossed for me!


Community Member

Re: Urgent Frame Relay Question

Ms. Scully,

I also may be showing my inexperience, but I recently have been having trouble setting up frame-relay. This may (probably won't) apply to you, but in my case I had very similar trouble setting up the frame-relay... the end result being I had the wrong wic cards. Do you by chance need 56k cards instead of fractional t1? If you are running 56k then the copied-pasted config for t1 won't work.... just a longshot thought. GL! =)

Community Member

Re: Urgent Frame Relay Question

if it is a 56k lease line, and not a frac t1 with just one channel allocated, then you need the 56k wic card. irregardless of configuration, 56k leased line uses pins 1,2, 7,8, and frac t1/t1 uses pins 1,2,4,5.

Community Member

Re: Urgent Frame Relay Question

Thanks for the suggestion, but nope - it's definitely T1. The only thing changing on the network is the router. Same WICs... Same config - in theory... (sigh)

Since I'm obviously such a Cisco GENIUS (NOT!), shouldn't I be able to just wave my hands over the device and have everything work perfectly? Or do I have to be a CCIE for that to start happening, lol?

Community Member

Re: Urgent Frame Relay Question

In case anyone stumbles across this, I finally have the answer!! We were taking modules from our old router (3645) to put into the new router (3745). The module that the T1 WICS were on was not supported by the 3745. We moved the WICS onto a different module and removed the unsupported one - frame relay came up beautifully - just like it's supposed to...

This is one I'll not soon forget!

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