PSTN vs. POTS and Understanding “Good Enough”

Jeff Pulver, someone I like a lot, and respect a great deal, and someone I believe wears a really big white hat, has a petition to the FCC, drafted wirth Tom Evslin (who I also like and respect).

I completely agree with Toim and Jeff in that all people want to do in a distaster is communicate and share key status with loved ones and others. They don’t care about QoS and perfect call quality. It’s far more important to be able to get the key message across than be able to hear a pin drop, in these cases.

Aswath notes about the primary recommendations of the petition:

These two suggestions taken together are beneficial for the society at large; state clearly when it could be invoked and the effective period; do not adversely impact any business prospects for the service providers. For these reasons, the petition should receive wide support and all of us should urge FCC to consider it favorably.

I agree.

Taking things a bit beyond that however, Om makes the very contrary assertion that the petition implies that “despite all the marketing dollars and early adopter fascination with VoIP, basic phone service from the bells is better on all counts, except price.”

  1. You lose reliability of the phone system.
  2. You sacrifice quality.
  3. You lose 911 service

I agree with Om here too. I would add that you may also lose your existing number (number portability doesn’t work everywhere, with all VoIP services, and if you do port your number to the VoIP service, you may never be able to get it back).

The other side of this coin is that VoIP services, at least as commercial VoIP services are conceived today, don’t really expose the promise of IP Communications to the user either. They mostly just offer the same old services, at a cheaper rate. They offer virtual numbers and ‘nomadicity’, and some offer a softphone service, but none of them offer anything near the richness we enjoy in other Internet applications. So not only does one lose the benefits of PSTN, they get few if any benefits of the Internet.

This is where this post gets difficult for me. I generally avoid speaking of my own commercial enterprises on this blog. However, in this case, I can’t avoid it. PhoneGnome was conceived exactly to address these kinds of issues.

We recognized five years ago what this recent Pulver/Evslin petition points out, that the Internet has a long way to go to achieve a few of the base attributes of the 125 year-old POTS network. More importantly, being involved in Internet architecture and design for 20+ years, I have a unique appreciation that changing the Internet to be more like the POTS network, as many are suggesting, is exactly the wrong thing to do. It is completely inconsistent with the exact thing that makes the Internet so powerful, so useful, so flexible. As Aswath mentions “This petition dilutes, if not totally eliminate the inherent advantage IP networks have during a disaster.”

The Internet is about being “good enough”. I mean this in an extremely broad sense, all the way from a low level technical description, to a very abstract application level, and even to the core of the operating and business mdoel. The POTS/PSTN network is about all or nothing quality. It is the ultimate falacy to say POTS/PSTN QoS is better than Internet QoS. The two operate on completely different principles. And people in their real lives have been enjoying these two models together, and getting immense benefit from them in parallel, for 10 or more years (depending on when one started using the net). Neither can fulfill the benefits of the other. There are times when one QoS model suits us better than the other.

This “good enough” aspect of the Internet is what makes it work, both technically and economically. It is what permits the tremendous variety of applications (uses for) the Internet that we enjoy. The Internet cannot support a POTS/PSTN QoS model, not because I say so, but because it is inconsistent with its very nature. If one tries to make it do that, or more importantly, if they succeed in doing that, the result will be a diffferent kind of Internet that will no longer give us the things it has provided for the past 20+ years. It will cost as much (or more) as the current POTS network to build and operate. Who knows — people may do it because it seems like the “right” thing to do, the “obvious” thing to do. But if it happens, the Internet will no longer be the Internet.

However, what PhoneGnome is about, is using the strengths of the two networks to give more than the sum of their parts – HERE AND NOW using the Internet as it exists today and the POTS network as it exists today. We get a great deal of benefit from the Internet, and Internet applications. We use them to give us things nothing else has ever given us before. That’s how PhoneGnome let’s people use the Internet too, to do new things, not just the same thing at a lower price, and all while not ignoring the very real and practical value of the traditional POTS network, and letting people enjoy those benefits too, simuletneously.

Since I talk about it here, I will include: a gratuitous link to

1 comment for “PSTN vs. POTS and Understanding “Good Enough”

  1. You are perfectly right. This whole situation reminds me of the beginnings of PC-based computing.

    Back then people would grind and point out that a PC will never be able to match the performance and computing power of proprietary mainframes and supercomputers. Look what happened: by combining these pieces of hardware that are just "good enough" to do the job (but an order of magnitude cheaper) in a smart way we ended up being capable of doing a lot more than a supercomputer (think of Google) with just commodity hardware.

    The same phenomenon is happening with telephony. Sure VoIP can’t offer five-nines but who cares? VoIP may represent one step back in quality when measured with POTS metrics but these criteria are no longer those that matter. It is just a small step back before a huge leap forward.

    Just like they are willing to trade voice quality for mobility with cellular phones, users will go for voice/data integrations at the expense of call reliability if necessary.

    The game is moving towards fields where POTS won’t be able to follow: voice/data service integration (presence, etc.). Let’s compare again when these become uiquitous and decide which one comes out first.

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