SIP trunking technology has developed a lot over the years so why haven’t more businesses replaced their old ISDN lines and PRI trunks with SIP trunks? What’s holding them back? When you compare the two, it’s clear that SIP is just better value.

SIP trunking can save money in a number of ways, including:

  • by reducing/eliminating the number of ports,
  • consolidating the communications infrastructure into centralized sites,
  • by enabling arbitrage between multiple providers

Despite these cost-cutting upsides, the move to SIP has not moved that quickly. This is because traditional telco’s are trying to keep existing customers on ISDN lines by either matching the financial incentive to move to SIP or simply by not communicating the existing of SIP-based services to their customer base.

From the service provider’s point of view, it makes sense to encourage the continued use of ISDN lines; they’re still capitalizing on a depreciated asset and avoiding the competitive potential of a SIP service procurement as well as the hassle of a potentially complex migration project. Beyond the price, concerns about the reliability of a SIP trunking service is also a factor that seems to hold businesses back.

The result is that while the number of business adopting SIP trunk services has risen, it’s not been an immediate switch. In a recent regional survey of those using a major UC vendor, more than 80% of the users represented said their organizations still used ISDN lines, having transitioned only partially to VoIP.

When an organization deploys SIP trunking in such hybrid environments, voice quality is at risk. Earlier this year, in a No Jitter postPhil Edholm raised the issue of ‘VoIPmaggedon’. Phil breaks down the different issues, but the main point was that the act of combining SIP trunking services with ISDN lines has been shown to introduce significantly increased latency.

The reality is that making the switch to a 100% SIP trunking-based telecommunications service can dramatically enhance voice-call quality. As the call stays as a VoIP call end-to-end, there is only one packet process. This can reduce latency by up to 67% versus a call with ISDN trunks on both ends and the carrier also using VoIP/SIP. It’s clear, therefore, that one key way of improving overall voice quality is to move to SIP 100%, in one complete transition.

To make the switch, the SIP trunking vendor needs to be carefully selected, based on how their VoIP and IP network is set up. How the SIP vendor peers with other service providers, both at SIP as well as at IP level, can have a dramatic impact on the voice quality. For example, some services have minimal peering, so a voice call to someone down the street may be peering between your carrier and theirs on the other side of the country — not desperately efficient.

For any organization, moving to SIP trunking to replace ISDN lines is not just a question of cost-cutting: it’s also about quality enhancement. Any company with ISDN trunks will start to see a rapid increase in call quality issues, as the number of VoIP endpoints continues to rise. So moving to SIP in one go, and avoiding hybrid set-ups, is not an option – it is a requirement.

Choosing the right SIP vendor is a critical part of that decision. Going with the wrong SIP/IP vendor could be a lot like jumping from the frying pan into the fire so our conclusion is: choose wisely!

Read the full article on UCStrategies