SHARE



ABOUT THE AUTHOR


Melissa Swartz
Melissa guides enterprise business clients through the complex process of finding the right communications solutions for their business, and getting...
Read Full Bio >>
SHARE



Melissa Swartz | March 23, 2016 |

 
   

SIP Trunking: Not a Simple Replacement -- Part 2

SIP Trunking: Not a Simple Replacement -- Part 2 A deeper dive into factors around facilities, configuration, and failover that can complicate a move to SIP trunks.

A deeper dive into factors around facilities, configuration, and failover that can complicate a move to SIP trunks.

portable

There are many ways that a move to SIP trunking is more than a simple replacement of current digital or analog services, as I began to explore in my previous article on No Jitter.

When moving to SIP trunks, you need to consider a range of factors related to facilities, configuration, and failover.

Facilities

There needs to be a way for SIP trunks to reach your network. You have two main options:

  1. A private connection such as MPLS. Some clients have added a connection to the SIP trunk provider, or have had the SIP trunks come in over an existing MPLS connection when the carrier was the same for both.
  2. OTT, or Over The Top services, where SIP trunks come in over an existing connection such as your Internet.

Of course, there can be costs for these services if it requires you increase bandwidth or add a new location to your network; this needs to be factored into your pricing analysis.

However, there are other considerations as well:

  • If you are using an OTT connection, you will lose QoS once your calls hit the public Internet. This can result in poor call quality, since the priority markings don't stay with the call. Even if you have a private connection, you can still run into call quality issues, but normally you can work with the carrier to get the issues resolved.
  • Are you on the same carrier the entire route, or is there another provider for the last mile? Adding another provider into the mix can create delays when there are problems with the service.
  • Depending on how services reach you, there may be different equipment needed on your end. Is the physical connection fiber, Ethernet, or bonded T-1s? You may need to buy some gear to support a different type of connection. If you are getting bonded T-1s, ask the provider how you will be alerted if one of the T-1s is lost. We had a client who was getting a lot of complaints about slow service and finally figured out that one of the bonded T-1s was down. It took some digging to figure out the cause.
  • Installation intervals are typically longer for private connections if you can't use an existing one. We are routinely seeing it take 90 days to install new MPLS connections.
  • Number porting can be unpredictable. We've seen it go very well, and we have seen nightmares. In some rural locations, numbers may not even be able to be ported. We've run into this scenario three times in the past year. The process can be frustrating and create delays (see this article).

When evaluating SIP trunking, be sure you understand:

  • How your provider will be bringing the services to you
  • Whether there is a different last-mile provider involved
  • What the physical handoff will be
  • How long it will take to get services and port numbers. (Then add more time into your project time line to account for unexpected delays. If you don't have any delays, it will give you extra time for testing).
Configuration

Once you get your SIP trunks installed, they must be configured properly to do what you want them to do.

If you are moving to SIP trunks at the same time that you are installing a new communications system, the system provider will usually include SBCs (Session Border Controllers) in its proposal. But not all of them do. If you are adding SIP trunks to an existing system, SBCs could fall through the cracks.

I'm often asked, "Do I really need a session border controller? I have a firewall already." My answer is always, "Yes, you need the SBC." And it must be configured correctly. It's been my experience that when there are problems with calls not going through, it's usually caused by the programming in the SBC or the firewall. Testing various types of calls (local, long distance, etc.) can uncover these types of issues.

Of course, this can also be another unanticipated cost item, so be sure that an SBC is included in your pricing analysis.

Your SIP trunks need to be configured so that 911 calls are routed to the correct Public Safety Answering Point (PSAP). This is especially important if you have multiple locations on centralized SIP trunks. We have clients who have left a POTS line in at every location to handle 911, due to liability concerns. Remember, if you lose power, you won't be able to call 911 on your SIP trunks, but that POTS line will still work.

Faxing can be an issue with VoIP and SIP trunks. Some carriers can change the settings in their network to work better with fax, but in my experience, that has not fixed all of the issues. Other fixes include slowing down the fax machines to 9600 baud, changing the codec to G.711, and tweaking the settings on the phone system. But even with all of that, faxes can still have issues. We have clients that have kept a PRI or analog lines just to keep their faxes working.

There is no standardization yet on SIP features. In fact, carriers will often use the same term but it will have different meaning to each of them. For example, there is a feature called SIP Refer. In the old days, we would have called it a "trunk to trunk transfer". Here's the scenario: An outside call comes in to a user, who then decides to transfer the caller to another number outside the system (such as a cell phone). For some providers, this would end up tying up two call paths, or sessions, including two sessions in the SBC, even though there is no one in the system on the call. For other carriers, this scenario might play out differently, as some might make the connection in their network so as to not tie up customer resources. Other providers still, by default, don't allow SIP refer, and you have to make sure that you request it. Don't assume that just because a term is used by multiple parties, that it has the same meaning to all of them.

Caller ID is another area where I have seen configuration issues. Outbound caller ID must be properly configured or it can override the settings in your phone system. Incoming caller ID can be lost when calls come through an IVR. Sometimes transferred calls will send out incorrect caller ID. I've also seen the wrong caller ID displayed when a user makes a call to conference in a third person.

To avoid problems with configuration issues:

  1. Create a test plan
  2. Execute the test plan
  3. Fix the problems
  4. Test again
Failover

Configuration problems can impact failover. I have a client who has multiple locations on SIP trunks that come into two separate locations for failover. A cable cut took out the SIP trunks in the main location, and DID calls failed over to the second site as planned. Their toll free calls did NOT fail over. The carrier did not configure them to fail over, even though it did configure the DID numbers to fail over. The toll free numbers were moved to the SIP trunks at a different time, and the carrier missed the failover programming. The same thing can occur when you have multiple SIP routes within an organization; all of it must be properly configured for fail over.

Be sure that you also know what triggers your SIP trunks to failover. My team and I were testing failover with a client, and we took down the phone system. No failover. We took down the data network. No failover. We unplugged the SBC, and then the SIP trunks failed over. That particular carrier doesn't see past the SBC into the customer's network, so for them, there's no failover as long as the SBC is operational. This is important information.

If you want to re-route numbers, how is that done? Most carriers have a portal that allows the customer to control the number routing. We have a client that regularly re-routes about seven critical numbers. In the carrier portal, there is no way to re-route all seven numbers as a group. Each number needs to be routed individually. I guess it's a good thing they don't want to re-route 700 numbers...

Many of our clients have a different backup carrier in place to allow them to continue service in case of an outage by their primary carrier. It can be tricky to get the SIP trunks set up to use another carrier service; but some are able to do this.

To avoid these failover problems, discuss your requirements with your SIP provider in detail, and (again) test.

"SCTC Perspectives" is written by members of the Society of Communications Technology Consultants, an international organization of independent information and communications technology professionals serving clients in all business sectors and government worldwide.

Follow Melissa Swartz on Twitter and LinkedIn!
@MelissaSwartz
Melissa Swartz on LinkedIn





COMMENTS




Enterprise Connect Orlando 2018
March 12-15 | Orlando, FL

Connect with the Entire Enterprise Communications & Collaboration Ecosystem


Stay Up-to-Date: Hear industry visionaries in Keynotes and General Sessions delivering the latest insight on UC, mobility, collaboration and cloud

Grow Your Network: Connect with the largest gathering of enterprise IT and business leaders and influencers

Learn From Industry Leaders: Attend a full range of Conference Sessions, Free Programs and Special Events

Evaluate All Your Options: Engage with 190+ of the leading equipment, software and service providers

Have Fun! Mingle with sponsors, exhibitors, attendees, guest speakers and industry players during evening receptions

Register now with code NOJITTEREB to save $200 Off Advance Rates or get a FREE Expo Pass!

January 24, 2018

Communications, collaboration, and contact center systems are all being delivered from the cloud, to more enterprises each year. With the cloud growing in strategic importance, the question is what

December 13, 2017

The two major vendors in the Unified Communications space, Cisco and Microsoft, are both strongly promoting their cloud UC deployments. If cloud UC is on your enterprises roadmap, but you dont want

November 29, 2017

As video conferencing use rises in the enterprise, businesses are looking for ways to bring this technology out of traditional conference room and make it more broadly accessible. That's made the h

December 20, 2017
Kevin Kieller, partner with enableUC, provides advice on how to move forward with your Skype for Business and Teams deployments.
December 20, 2017
Zeus Kerravala, principal analyst with ZK Research, shares his perspective on artificial intelligence and the future of team collaboration.
December 20, 2017
Delanda Coleman, Microsoft senior marketing manager, explains the Teams vision and shares use case examples.
November 30, 2017
With a ruling on the FCC's proposed order to dismantle the Open Internet Order expected this month, communications technology attorney Martha Buyer walks us through what's at stake.
October 23, 2017
Wondering which Office 365 collaboration tool to use when? Get quick pointers from CBT Nuggets instructor Simona Millham.
September 22, 2017
In this podcast, we explore the future of work with Robert Brown, AVP of the Cognizant Center for the Future of Work, who helps us answer the question, "What do we do when machines do everything?"
September 8, 2017
Greg Collins, a technology analyst and strategist with Exact Ventures, delivers a status report on 5G implementation plans and tells enterprises why they shouldn't wait to move ahead on potential use ....
August 25, 2017
Find out what business considerations are driving the SIP trunking market today, and learn a bit about how satisfied enterprises are with their providers. We talk with John Malone, president of The Ea....
August 16, 2017
World Vision U.S. is finding lots of goodness in RingCentral's cloud communications service, but as Randy Boyd, infrastructure architect at the global humanitarian nonprofit, tells us, he and his team....
August 11, 2017
Alicia Gee, director of unified communications at Sutter Physician Services, oversees the technical team supporting a 1,000-agent contact center running on Genesys PureConnect. She catches us up on th....
August 4, 2017
Andrew Prokop, communications evangelist with Arrow Systems Integration, has lately been working on integrating enterprise communications into Internet of Things ecosystems. He shares examples and off....
July 27, 2017
Industry watcher Elka Popova, a Frost & Sullivan program director, shares her perspective on this acquisition, discussing Mitel's market positioning, why the move makes sense, and more.
July 14, 2017
Lantre Barr, founder and CEO of Blacc Spot Media, urges any enterprise that's been on the fence about integrating real-time communications into business workflows to jump off and get started. Tune and....
June 28, 2017
Communications expert Tsahi Levent-Levi, author of the popular BlogGeek.me blog, keeps a running tally and comprehensive overview of communications platform-as-a-service offerings in his "Choosing a W....
June 9, 2017
If you think telecom expense management applies to nothing more than business phone lines, think again. Hyoun Park, founder and principal investigator with technology advisory Amalgam Insights, tells ....
June 2, 2017
Enterprises strategizing on mobility today, including for internal collaboration, don't have the luxury of learning as they go. Tony Rizzo, enterprise mobility specialist with Blue Hill Research, expl....
May 24, 2017
Mark Winther, head of IDC's global telecom consulting practice, gives us his take on how CPaaS providers evolve beyond the basic building blocks and address maturing enterprise needs.
May 18, 2017
Diane Myers, senior research director at IHS Markit, walks us through her 2017 UC-as-a-service report... and shares what might be to come in 2018.
April 28, 2017
Change isn't easy, but it is necessary. Tune in for advice and perspective from Zeus Kerravala, co-author of a "Digital Transformation for Dummies" special edition.
April 20, 2017
Robin Gareiss, president of Nemertes Research, shares insight gleaned from the firm's 12th annual UCC Total Cost of Operations study.
March 23, 2017
Tim Banting, of Current Analysis, gives us a peek into what the next three years will bring in advance of his Enterprise Connect session exploring the question: Will there be a new model for enterpris....
March 15, 2017
Andrew Prokop, communications evangelist with Arrow Systems Integration, discusses the evolving role of the all-important session border controller.
March 9, 2017
Organizer Alan Quayle gives us the lowdown on programmable communications and all you need to know about participating in this pre-Enterprise Connect hackathon.
March 3, 2017
From protecting against new vulnerabilities to keeping security assessments up to date, security consultant Mark Collier shares tips on how best to protect your UC systems.
February 24, 2017
UC analyst Blair Pleasant sorts through the myriad cloud architectural models underlying UCaaS and CCaaS offerings, and explains why knowing the differences matter.
February 17, 2017
From the most basics of basics to the hidden gotchas, UC consultant Melissa Swartz helps demystify the complex world of SIP trunking.
February 7, 2017
UC&C consultant Kevin Kieller, a partner at enableUC, shares pointers for making the right architectural choices for your Skype for Business deployment.
February 1, 2017
Elka Popova, a Frost & Sullivan program director, shares a status report on the UCaaS market today and offers her perspective on what large enterprises need before committing to UC in the cloud.
January 26, 2017
Andrew Davis, co-founder of Wainhouse Research and chair of the Video track at Enterprise Connect 2017, sorts through the myriad cloud video service options and shares how to tell if your choice is en....
January 23, 2017
Sheila McGee-Smith, Contact Center/Customer Experience track chair for Enterprise Connect 2017, tells us what we need to know about the role cloud software is playing in contact centers today.