Why SIP Problems Persist--and What to Do About Them
SIP trunk problems aren't usually technology issues, which means they are fixable with proper training and better implementation processes.
The survey results, which reflect the input of almost 1,100 respondents, show fewer problems have cropped up on the equipment side than in previous years. This isn't to say that equipment vendors don't have their problems; it's just that this year's survey respondents report having a greater number of problems with service providers.
Middle of the Pack
Session border controllers (SBCs) and network address translation (NAT) devices sit at the boundary between the IP PBX and the provider. Respondents associated about 21% of SIP trunk problems to these edge devices -- fewer than they attribute to providers but more than they consider the fault of IP PBX vendors. In this year's survey, IP PBX vendors accounted for 16% of the problems; this is a major improvement over 2013 and 2014.
Note that SIP trunk problems aren't usually technology issues. Rather, the problems stem from mismatches, improper configuration settings, impatient and inexperienced installers, poor training, and poor documentation.
Survey respondents indicated that they consider value-added resellers (VARs), the fifth component in SIP trunk implementations, as the weakest participants. As you can see below, results show a lack of confidence in VARs and hosted VoIP providers.
Problems at the Edge
When compared to 2014 and 2013 survey results, some problems with the SBC and NAT devices have worsened. The table below compares the percentage of problems reported over the last three years.
How can these problems persist year after year? The survey results are public. Aren't the right people paying attention?
Let's take a closer look at a few of these:
- One-way audio remains the dominant issue. Resolving one-way audio is one of the many reasons for installing an SBC in the first place, so there really should be no problem here. That points to misconfiguration as the most likely source of a problem. The same is true when the problem is a lack of audio altogether.
- Codec issues are still high on the problem list. People configuring this type of specialized equipment would be expected to have a good understanding of codecs. Again, the problems here most likely involve configuration issues, those specifically produced by ignorance or negligence. With the appropriate skill set, codecs can be easy to configure correctly and test thoroughly.
- SBC registration failures are frustrating because the loss of the SBC is the loss of SIP trunks. Unless the SBC configuration is fault-tolerant, it can present a single point of failure. Test thoroughly and work with the vendor to determine if the offered products come with any known reliability issues. Unless you keep testing the SBC yourself for a year or more, you cannot calculate its reliability. You have to depend on what the vendor tells you.
IP PBX Problems
That the IP PBX generates fewer SIP trunk problems is gratifying to see. Let's take a closer look at these, too:
- The single biggest source of problems is manual configuration errors, dropping two percentage points -- from 60% to 58% -- from 2014 to 2015, but still dominating the problem list. These could be the result of ignorance, negligence, impatience, and poor training. Whatever the cause, proper configuration testing should reduce problem incidents.
- Codec issues are preventable with the proper inspection of settings. Could we have an automated validation check to match codecs?
- Registration failures and SIP trunks dropping are attributable to misconfiguration or poor documentation.
- No licenses is a really ridiculous reason to have for experiencing SIP trunk problems. Don't enterprises know for what services they are paying? This should not happen.
Learn the Survey's Lessons
Enterprises are rapidly replacing T1/PRI trunks with SIP trunks. In comparison, these legacy trunks have few problems. Enterprises, of course, want their SIP trunk installations to be as clean as legacy trunk installations.
All five parties -- IP PBX and SBC vendors, trunk providers, VARs, and the enterprises themselves -- should develop a good working relationship before, during, and after the implementation. Problems after cutover won't disappear, but VARs and enterprise IT staffs must take responsibility for getting the chain of components to work together seamlessly and to stop the fingerpointing.
You can blame most of the aforementioned problems on ignorance, which points to the need for more training and experience, proper documentation, and more care to reduce typographical configuration entry errors. An enterprise can avoid all of these with installer patience, good training, and independent configuration verification.
Join me at Enterprise Connect 2016, coming March 7 to 10 in Orlando, Fla., where I'll be moderating the session, "SIP Trunking Triumphs and Torments." Register now using the code NOJITTER and receive $200 off the current conference price.)