ISDN PRI - What is it for? 1

[slyride]

Hello,
I am new to this and am trying to learn more. I am going over our contract and am curious about the ISDN PRI. It is provided with the sites that house our servers. The note are:
The Colo site has a 3Mbps Frame Relay port, 1 ISDN PRI, and 1 Price Protected Internet T1.
Site 2 has 1.5Mbps port with a 768Kbps CIR PVC and an ILEC provided ISDN PRI.
33 Remote Sites have 128k frame relay ports and 64k CIR PVCs back to the host site.(Colo).
1 Remote site has a 64k frame relay port and 64k CIR back to the host site.
So what I understand is this.
1 Price Protected Internet T1 is our connection to the internet.
They said nothing of a CIR for the Colo which may mean there is no guarantee of speed?
Site 2 is guaranteed 768K.
All remote sites are guaranteed 64k.
So what are the ISDN PRI's? Backup lines?
TIA
L

 

[workaholic24x7]

It appears that you are using ISDN/PRI as a 'dial back up' means in the event you lose your FR/connection. Some customers implement a back up method to their FR network if the data is critical. It appears the Colo Site and Site 2 are critical data, thus the reason for the ISDN/PRI. A FR network is desgined typically from the remote to Hub or remote to 'COLO'...in this case all the remote's have various CIR's back to the Colo site...and the CIR is a duplex PVC.

 

[slyride]

workaholic24x7 - Thanks, that makes sense. I just have to figure out how we would use it now. I assume that the provider should know.
Thanks again.
Leon

 

[workaholic24x7]

Leon.... or whoever is providing the router/equipment also knows because they should have implemented the isdn back up feature in the router to work w/ the appropriate interface.

 

[nemes75]

keep in mind that the ISDN circuits can be utilized as local dial tone service. Im not sure if you are looking at the Visio or an actual bill.

 

[slyride]

The setup was in place when I inheritted it, but I looked at the router and it looks like the interface is there. Would it roll over if the frame line went down by itself or would I have to do configuration on the router?
Thanks
Leon

 

[gdschertz]

If it is used for backup there will be a routing statment that uses the isdn pri ip address as the gateway. it will have a higher number in the metric that the frame relay route.

 

[julius1]

If you are an ISP, most use the ISDN PRI for the customer to actually dial thru to reach your modem bank/router. If it is for back up, they generally do not use a pri circuit for that, but rather a BRI. That is usually configured to go to another destination to allow for connectivity in case the lease line goes down. That is basically "out bound" the PRI is generally in bound depending on the telco's tariff's. Some telemarketers use the PRI as well for out bound calling as does some business customers to track for billing, and or to send and receive caller ID. Caller ID does not work on a BRI.

Im a Telco guy, I can get you where you want to go, but I can't guarantee it will work when you get there!

 

[lui3]

you might also see a dialer interface configured with dial watch commands to provide dial backup in the case of a routing failure. that way the ISDN line would be able come backdown once the frame relay came back up.

 

[julius1]

That would generally be on the BRI's, not normally on the PRI's.

julius.gazdag@centurytel.com
Im a Telco guy, I can get you where you want to go, but I can't guarantee it will work when you get there!

 

[tomsullivan]

pri for redundancy is not nor has ever been a cost effectice solution, it would make alot more sense to utilize a 2nd isp or alternate entrance facility for redundancy/disaster recovery. that way you could utilize the bandwidth 24X7 not just when the dedicated circuit fails.
tom
617-469-3310

 

[slyride]

Thanks Tom and all
It is looking more and more like it was never set up. Hopefully we have not been paying for it. We are looking at setting up a VPN connection to use for redundancy, possibly also replacing the frame lines with vpn.
Thanks
Leon

 

[tetaguila]

the better way to implement fully redundancy is to add another isp that will provide you a technology similar to bgp4, meaning the ip address that will be assign to you is routable to other isp, they said linux can now handle it..im stil researching for it, take time to research also and let us know....

 

[slyride]

Thanks tetaguila,
I'll look into it and post what I find out, although right now we don't have any Linux expertise on our team so that's going to make things hard, unlessone of us decides to take it on, but pretty busy with other stuff right now...
More to follow.
L-