Can I use SIP if my PBX is behind a NAT firewall?

Yes, using SIP registration, this is possible.

Two Types of SIP Providers

In my experience, I’ve come across two types of organizations who sell SIP service.

Provider 1

This is a traditional LEC or CLEC who offers SIP as a “me too” service—or in addition to their traditional analog lines, PRIs, Internet T1′s, MPLS, etc. Often they will require that you purchase their T1, provision 23 to 30 SIP trunks on it, and charge you the same as a standard PRI. Additionally, they can’t / won’t offer the additional flexibility of SIP trunks (porting numbers across calling areas, fail over, etc.) I haven’t seen very many of these products sold by agents or direct sales reps. It makes sense to me. Why sell an unknown (SIP) when you can sell the good old all mighty PRI? After all, there are no cost savings advantages. Note, this is me generalizing. It’s not the case with all SIP providers. In fact, I’ve recently worked with one that requires you to use their T1, but will offer the porting flexibility and cost savings benefits of SIP (.01/minute LD, 40+SIP trunks on the T1, etc).

No wonder less than 10% of businesses have moved over to SIP. It’s not because it doesn’t work, it’s because they don’t know about it! Your average telecommunications sales representative isn’t educating their customers.

Provider 2

The second type of SIP provider breaks the traditional mold of telecommunications providers. They can offer SIP trunks over your own bandwidth, can port and source numbers from most areas of the country, can provide fail-over, and are usually MUCH less than your traditional CLECs and LECs. [ read more ]

SIP Trunks Without an IP PBX

Can this be done? We’re doing it. By using third party equipment, we can terminate SIP trunks and convert back to traditional PRI signaling. This extends the benefits of SIP trunking to those that don’t want to upgrade their PBX yet.

Don’t get me wrong – if your organization needs to upgrade their phone system, but doesn’t have the money, by all means use the 40% – 70% SAVINGS associated with SIP trunks to justify the purchase. We’ll often wrap the phone system acquisition into a lease, convert the customer to SIP trunks, and still save the customer money AFTER the lease payment.

Sorry, back to converting SIP trunks to traditional connections…So far it works great. Depending on the scenario, it’s solved some other issues too. In our testing, we’ve realized that  this SIP conversion  equipment drastically speeds up the fail-over between two Internet connections. That’s because this equipment negotiates between the two Internet connections and reestablishes SIP trunking on the backup should the primary fail. In some cases, we were on a live call when we killed the primary Internet connection and didn’t drop the call! Other times we dropped the call but the SIP trunks were back up within seconds. Ask your traditional PRI provider to do that! [ read more ]

Do I need a specific type of VOIP phone system?

Different SIP providers are certified to work with various IP phone system manufactures. Some IP phone system manufactures require additional equipment to operate. Check with an Access Technologies representative to determine if your phone system is certified.

Note: It is important that you test your phone system EXTENSIVELY with the SIP provider before implementing production systems with SIP. Often, demo trunks can be ordered on a monthly basis for this purpose. Test all important features like call forwarding, conferencing, transferring, etc. Often a phone system can be “certified” but certain features can be missing. As an agent, we’ll try to get you in touch with another agent who is using the same type of phone system for technical / feature discussions.

SIP – A great disaster recovery solution!

Beyond simply saving large sums of money, SIP is also a great disaster recovery / business continuity solution. Up until now, we have just had to accept the fact that we can’t build any sort of reasonable amount of redundancy into our phone services.  The proper deployment of an IP phone system and SIP trunking providers has changed that and Inflow has been leading that charge for over three years now!

Our Portland, OR and Northwest-based customers love us.  Every Allworx / ShoreTel phone solution that we propose for our customers has a full disaster recovery component to it.

Unlike traditional wire-line technologies like analog and PRI, VOIP / SIP trunking providers provide dial tone over an IP connection(s).  Because of that, a whole new world of dial tone redundancy is available to the organization.  Currently, if your PRI gets severed by the all-mighty back hoe, your options are pretty much limited to waiting for the Local Exchange Carrier (LEC) to restore your service.  In the meantime, you’re sitting without the lifeblood to your business – your telephones!

With the proper SIP providers, we can deliver dial tone over one connection (T1, fiber optics, etc).  If that connection to the world fails, we can automatically fail over to an alternate IP connection (cable, DSL, etc).   This is all made possible because SIP trunks are merely packets containing voice, traversing the network.  Like a standard Internet connection, we can re-route those packets over an alternate connection and re-establish communications with the SIP trunking provider.  Since when could we provide 100% dial-tone fail-over with traditional analog lines or PRIs?

Often, we recommend our customers use two different connections with different physical mediums (copper vs. fiber optics, coax vs. copper) to facilitate (1) their primary Internet connection and (2) their primary voice (SIP VOIP) connection.  With the proper network configuration, we can enable these connections to BACK EACH OTHER UP. How’s that for an SLA?

In theory it’s simple.  However, Inflow Communications has been perfecting the manner in which it’s done with a unique solution that combines SIP trunks, a business phone system (preferably an IP phone system), and adjunct SIP / networking technology.  It works, we have many happy customers whom have benefited from it (and they’re happy to talk to you).

Oh yeah, you can load balance and fail SIP across physical locations too….

Oh yeah, if both IP connections go away, we can automatically fail to copper POTS line…