Beyond BRI??

Unanswered Question
Feb 7th, 2007

I have 6 BRI lines attached to our router for DDR backups. We are finding we need to double these BRI lines to keep up with the number of remotes.

The problem is my router doesn't have enought slots.

Can I replace all those BRI lines with a single PRI or does PRI not work the same?

This is strictly for data communications.


I have this problem too.
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sundar.palaniappan Wed, 02/07/2007 - 15:04


Unfortunately, that's not possible with the BRI components. The circuit has to be provisioned as a PRI by Telco and you would need a serial interface on the router and CSU/DSU to connect a PRI to the network. With PRI, you can subscribe to whatever # of channels you desire and do not have subscribe all 24 channels.



christopher.s.d... Wed, 02/07/2007 - 15:10

Yes you can use a PRI assuming the hardware supports it. A PRI runs over T1 so you will need a T1 interface. Since the PRI has 23B+1D channel you can terminate 23 64k data calls from BRIs at remotes.


To avoid confusion as stated above BRIs do not work the same as PRIs different line coding,line rate, etc. So you would need a t1 csu/dsu as stated above, but you can get a PRI to terminate BRIs at remote sites if you have the right hardware.

dennylester Wed, 02/07/2007 - 15:21

Hi Christopher,

Thank you for responding to me. I have a Cisco 2811 router with a free port open on a VWIC2-2MFT-T1/E1 card. So, if I order a T1 configured as PRI does it pretty much setup the same as a BRI with each channel having a SPID?

So far my circuit vendor told me a PRI wouldn't work this way and the data could possibly get corrupted with the compression used on the backend. Perhaps they have never sold a PRI configured for data only.



dgahm Wed, 02/07/2007 - 17:55


We have over 40 remote sites in 3 states with BRIs dialing into 2 sites with PRIs. Another 10 sites dial into the same PRIs using modems, though this requires a digital modem module in the PRI router. The PRIs use a single phone number, and that does not have to be configured in the PRI router. Our PRI routers are 3640s with channelized T1 NMs with internal CSU/DSUs. Your 2MFT-T1 would probably not work.

Don't know what your vendor is talking about. This setup performs very well. I can post a config if you decide to try it.

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