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Firms who sell SIP Trunking should be licensed – Here is why …

By February 10, 2013 Voip

For over 10 years now, we have been looking at VoIP as a mechanism to reduce costs. And for over 10 years now, we have seen the various vendors (Nortel, Mitel, Avaya, Cisco, NEC etc. etc. etc.) declaring their turf and superiority. The reality, it has never really been about the actual phone system, but more-so about the underlying network.

The real savings for this come by way of a neat word called ‘SIP’.

What is SIP

The Session Initiation Protocol (SIP) is an IETF-defined signaling protocol widely used for controlling communication sessions such as voice and video calls over Internet Protocol (IP). The protocol can be used for creating, modifying and terminating two-party (unicast) or multiparty (multicast) sessions.

What is SIP in English

This is fancy technical speak that basically says: “it is the way we deliver a phone like to your office”.

What does this mean for your business?

Phone systems have really two sides to them:

Trunk Side – the connection out to the Public Switched Telephone Network (PSTN) which is where the dial tone for our inbound and outbound calls come from (right now, you would consider this to be the actual phone line or phone lines that you pay monthly for).

Station Side – the actual link to the phone on your desk.

Funny thing, most IP phone systems produce an actual ‘ethernet’ phone, into a box that then translates all this lovely ethernet into their own respective protocols with nasty terms like MiNET , UNIStim , Skinny, MGCP. Loosely translated, they mean they are not SIP, but rather, a nasty proprietary protocol what means despite being ‘IP’ or ‘Ethernet’, it only supports their own infrastructure. Kind of a sad story to realize that most vendor’s state of the art equipment is not actually state of the art.

Remember the old days of the old IBM Mini Computer and Mainframes? (not to pick on IBM… but it is the first thing that popped in my mind). You bought an IBM Computer, which used an IBM printer, which used IBM cables which used IBM Software. Today…. most phone system vendors still work this way. They say they don’t… but… they do.

What does a SIP offering look like?

There is a business side, then a technical side.

First the business side:

At Frontier (as an example), we do two things. First, we can deliver the phone line equivalents that ultimately can replace the phone lines that you have. They can come in three flavors:

Type 1: Metered (or pay as you go): Pay a small per minute inbound and outbound rate for the use of the channel.

Under Type 1, All calls terminated to exchanges covered by our network (ON-NET) are charged at a rate of roughly 2.5 cent/min. All incoming calls are charged 2.5 cent/min as well. Outgoing calls outside our network and anywhere in continental USA and Canada are charged 2.5 cent/min. The rate is lower with volume. 800 Calls are considered rated calls and would be charged the per minute fee.

Best application for a Type 1 Trunk:

  • Occasional use
  • Retail sites or Quick Service Restaurants with limited use
  • Sites who predominantly call ‘long distance’ locations (since the usage and normal LD rates are basically the same, the trunks are effectively free when compared to similar models).
  • Sites with heavy 800 inbound usage
  • Sites with seasonal or heavy use fluctuations

Type 2: Unlimited Inbound, Metered Outbound

Under Type 2, Regular inbound calls received are included on a flat rate per month fee. All calls terminated work the same as our Type 1 channels. 800 Calls are considered rated calls and would be charged the per minute fee.

Type 3: Unlimited Inbound, Unlimited Outbound

Under Type 3, Regular inbound calls received are included on a flat rate per month fee. All outbound calls in the local calling area are also included. Calls outside of the local calling area as well as 800 Calls are considered rated calls and would be charged the per minute fee.

Second, the business side:

There are two ways to connect to a SIP provider. The wrong way and the right way.

A Public Connection – Over the Internet (we call this the terrible way)

A Private Connection – A link that is for the exclusive use of your voice traffic (we call this the right way)

Benefit of a Public Connection.

There really is only one benefit. Cost. It is a provider of SIP trunking’s way of saying ‘hey, connect to us via this IP address, and if it does not work, no worries, it is your problem not ours’.

Does it really not work?

Think of it this way. It works between 60- 80% of the time. Unlike a data packet, degradation is not that obvious, but with voice, you will see it immediately.

Here is an example of a service provider’s message to their customers during one of their own Internet based attacks:


The core routing facilities have registered a high volume network IP flood exceeding all the GigaBit interfaces physical limits.

As a result the connectivity handled by the core router has become intermittent and the VoIP switches have experienced a period of IP based Denial of Service, causing an outage.

Prevention Measures:

Applying a more segregated routing and firewall filtering policy, designed to increase the protection of the core services.

Want to know that it sounds like when degraded? Here is an example.

In English?

Their traffic was attacked as it sits on the public internet. While this happened, everyone on their network using their service had degradation, or no service to speak of.

With a Private Network, you are not subject to external vulnerabilities.


Like everything, if you are going to try a new technology, make sure you don’t put your business at risk. You can save money with SIP, big money, but factor some of the savings as an investment into your current infrastructure.

For example, you can use your Internet connection as a reasonable transport or ‘delivery’ method for your SIP trunks, just make sure you vendor is ‘well peered’. As an example with Frontier, we use a private connection to connect you to ‘us’, from there, we make a per packet determination of what needs to go to the Internet and what needs to hit the SIP proxy. It is a better way of doing it, and it eliminates the risk.

Short answer, try and minimize the number of finders to point at the multiple providers if/when there is a call degradation issue. For certain, the PBX (phone system) people will blame the SIP providers, the SIP providers will blame the Broadband and PBX provider and the Broadband provider will blame everyone.