Backup PRI Line?

[John Apricena]

Hello Support,

Is it possible to run dual PRI's that can route over the same phone numbers through the backup PRI in the event your primary PRI goes down? If so, what devices are typically needed for this?

Really am seeking a solution to keep our phones afloat in case our primary PRI goes down, so any solution would certainly be helpful. 

Thanks in advance!

[Chris Deren]

For outbound you are in full control, so simply configure your dial peers accordingly with preference command, or use trunk group configuration (assuming SIP or H323 config), if MGCP list accordingly in route group. 

For inbound this is on telco and the only way to make it work is to have the telco company put both PRIs in common trunk group.

Chris

[John Apricena]

Thanks Chris!

We were really looking to use two separate providers for the PRI trunks though. We assume that if that ISP is having an issue, both our PRI lines will go down from them. 

Is it just as simple as running the two separate PRI lines into a PBX and configuring the PBX as needed? Thanks again Chris!

[Chris Deren]

Well, not that simple.

Again, lets separate inbound from outbound:

Outbound - You can certainly use both PRIs for outbound calling as long as the ISP does not do ANI screening, so if they only allow outbound calls with their calling party presentation you would need to mask the caller ID on the secondary PRI to something they trust

Inbound - you cannot have PRIs from different carriers in one trunk group, so each one would be responsible for different DIDs. I suppose you can do second set of DIDs and then perform translations to internal extensions, but to me it's not worth the effort.

[John Apricena]

Understood. So, a company looking for PRI redundancy just uses multiple trunks from the same ISP in most cases if they want numbers to stay the same?

[Chris Deren · Accepted solution]

Correct, another common approach is to have separate Local and LD ISPs, having one provider to handle Local calls, and another for Long Distance.

Not sure if you are looking to implement new system or add onto an existing and which country you are at, but SIP trunking is the technology of choice for new implementations and same consideration needs to take place, hence many larger customer opt to get SIP trunks from 2 different carriers.

[John Apricena]

With the SIP trunks from two providers scenario, in the event an entire trunk goes down from one provider, do larger companies configure numbers incoming and outgoing to route the same DIDs over the backup carrier?

[Chris Deren]

No, you cannot share DIDs across providers, typically customer would use one provider to server some locations and another provider to server other locations, so that when one trunk is down it does not affect inbound calling to entire enterprise.

[Tagir Temirgaliyev]

ask your telco providers what they can do may be for extfa charge