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If you cannot send me an emergency text message that has a distinctive sound when it arrives and is guaranteed to arrive in a timely manner, don't bother sending it

SMS Alerting Falls Short, Just Ask Obama

Monday, August 25, 2008

There is a new law that says FEMA will decide when to send SMS messages to people who need to be alerted to a problem. However, Obama just proved beyond a doubt that SMS is NOT a mission-critical service. Thousands of SMS messages announcing Obama's running mate were sent, but many people did not receive them until the next day and many newspapers awaiting verification of his selection missed the front page placement of the news because the alert arrived after deadlines passed.


Was this because the alert was sent too late? No, it was sent on time but the delays in delivering SMS messages are unpredictable. The more you send, the less likely people are to receive them in a timely manner. Each intended recipient's cell phone has its own phone number so each message must be sent individually-SMS messages are sent sequentially, one number at a time. In the case of Obama's text message, networks were clogged with SMS traffic that had to wait its turn.


This probably wouldn't happen in an emergency situation, but hackers and others who wanted to have a little fun were busy sending out bogus text messages about Obama's running mate as well.


Now, in addition to the typical SMS message delivery delays, with the new federal system of alerting, FEMA will decide which messages qualify for emergency SMS notification. Remember Katrina when the Federal Government sat on its hands for several days before deciding New Orleans was in trouble? Think about the same people at FEMA calling a meeting to determine whether a request for an emergency SMS message was warranted. If I were mayor of New Orleans, I would want to be the one to say when to send an SMS alert to the citizens of my city.


We have been taught to call 911 if we think there is a problem, and we are told not to wait-call 911 and ask for help. If the SMS rules were applied to 911 calls, the way I read them, we would need a vote of a committee within FEMA before we could dial the phone. This makes very little sense and the reality is that even after FEMA "blesses" an emergency alert to be sent out, SMS is not the most effective way to alert people, as the Obama SMS text message has shown.


What if Obama's message had been about a major disaster? It might not have reached all the media, radio stations, TV stations and press, and those who did not receive it would not have known there was a problem. They might have received the alert the next day or the day after. And, honestly, I get so many junk text messages that I usually ignore them. If one was an alert for me to vacate my house because of an impending storm or fire, I probably wouldn't notice it.


If you cannot send me an emergency text message that has a distinctive sound when it arrives and is guaranteed to arrive in a timely manner, don't bother sending it. Obama, who is said to be technically literate, was not aware of the issues with SMS or text messaging-very few people are. They simply assume that when a message is sent to a phone it will arrive quickly and alert the person it was sent to. The reality is that text messages are not guaranteed-delivery messages, and the time to deliver one can run from minutes to non-delivery. My understanding is that any undelivered messages are flushed out of the system after 72 hours. SMS is not a mission-critical system.


I hear there are things afoot to change how SMS is delivered and several companies are working on a way to send messages to thousands of people at the same time, but this probably is not true SMS since SMS requires messages to be sent to specific phone numbers. I see two problems with changing how SMS is delivered. The first is that all of us (260 million) will need a new phone and it will take at least five years for everyone to trade in their phones for new ones, especially if they have to sign up for a full two years of service. (There were still subscribers with analog phones when analog was turned off in February 2008.)


Summarizing SMS as it is today, each SMS message must be sent to a specific phone number and even "group" SMS is nothing more than a string of phone numbers dialed sequentially, it is not a guaranteed-delivery service and many systems flush out undelivered SMS messages after 72 hours.


When I receive an SMS message today, my phone vibrates or sets off a tone. There is no distinction between an emergency alert message and a message from anyone who sends me SMS messages during the day. And there are times when my phone has to be turned off-in a doctor's office, in a classroom or other settings where there are signs indicating that the use of cell phones is not permitted. Then, of course, there is the period of time when I am on an airplane with my phone turned off, or just plain out of range. Some of these issues will affect any type of mass alerting system, but most of them can be resolved by finding a different technology to deliver the messages.


You could liken SMS alerts to reverse 911 systems that are being deployed in many cities and counties around the nation, but with one difference. Many of these reverse 911 systems are connected to multiple phone lines and really can simultaneously deliver a voice message to groups of phones. But during the recent Gap fire just north of Santa Barbara, as well as the fires in Orange and San Diego counties, the reverse 911 systems still took many hours to notify a relatively small group of people who needed to evacuate. Two hours during a fire storm can mean the difference between getting out and being trapped in your home.


Obama's attempt at SMS alerting should be considered one of many warnings to the powers that be. SMS is NOT a mission-critical method of notification for large groups of people. In this case, the only harm was to reporters who were waiting for confirmation of his choice of running mate and missed their paper's deadline, and the disappointment of people who expected to be among the first to know, only to find out from news reports before they received their SMS notification.


I haven't heard any comments from network operators about SMS overload, but in a situation where we are trying to notify people in large numbers, even in a small portion of the country (say New Orleans and surrounding areas), there will be some network congestion. SMS messages are not carried on the voice channels, and only a finite number can be sent per hour over the data channels.


This country is having problems solving its first responder communications issues, and progress since 9/11 has come only because the first responder community has not waited for the Federal Government. Some seem to think they have alerts to the general population covered. I don't think so. The real solution for public alerts needs to include all forms of communications-radio, TV, SMS (perhaps), reverse 911, etc. Trusting only one method to get the message out is not a good idea, and if SMS is the method of choice, many alerts will be received too late to seek refuge from the storm, fire, etc.


As a final note, if I were a mayor or governor, I would not want to have to wait for someone at HLS or FEMA to decide whether or not to send out an alert to the citizens I govern. I can see it now: [FEMA Person] "If I authorize this alert and my boss disagrees that it was necessary, I might get in trouble. Perhaps I should wait a little while or try to reach my boss (who is at a party, on vacation or somewhere unreachable)."


I, for one, would trust the judgment of a mayor or a governor. In Florida, the governor was criticized for his too-early declaration of an emergency-but it turned out he was right and because of his assessment of the situation, the state was better prepared. I don't for a moment think SMS or any one technology by itself is the answer for alerting the general population. Better solutions are out there.
Andrew M. Seybold

COMMENTS: This is an archived post. Commenting is no longer available.

Chris Purpura - 08/25/2008 18:44:48

this is why for enterprise applications and embedded systems, Aeris has implemented our SMS Direct service which carries and delivers with priority, acknowledgments and retries, SMS in a mission critical manner. We talk about SMS's lack of reliability all the time, but customer just don't believe it well enough. This is such a great example. Thanks, Andy

Andrew Seybold - 08/25/2008 18:58:26

Chris--I did remember that Aeris did something to make SMS more robust and that is good, but there are still many problems with it when used for mass reporting. And, of course, adding a layer of people who have to give their permission before a message is sent out makes it even worse.

Nick Ruark - 08/25/2008 21:01:23

hmmmm.....maybe we should thank the Obama camp for pointing this issue out, albeit his SMS message was only "mission-critical" to certain selected recipients.

Andrew Seybold - 08/25/2008 21:03:26

Thanks for the comment Nick--and yes, perhaps with the national attention this has people will learn the truth and not count on a technology which has a lot of flaws when you are talking about thousands of text messages.

Fred B - 08/26/2008 08:46:11

Mostly right I think. However it isn't technically necessary to have a new phone to solve the batching and priority issues - they can be done at the system level. And I'm not so quick to assume there's a technical fix to getting messages absolutely everywhere. Lots of problems to solve there, some of them quite daunting technically, some require cooperation (like on airplanes). But your basic message is certainly right. In fact you could go further. Most emergency types assume the cell system is out during an emergency. In the San Diego fire, the fire quickly incinerated the phone lines to cell towers, the cell tower batteries fail after a few hours. I believe it was about a month to get that all back working in many areas. In addition people calling in an emergency quickly overwhelm the limited capacity. These kinds of events are not unusual and happen in rainstorms, quakes, etc.

Alexander Pournelle - 08/26/2008 17:48:56


I appreciate that SMS is not mission-critical for conversation, and I'm glad you raised the issue. Unless your phone makes a distinct HEY YOU MIGHT WANT TO READ THIS RIGHT NOW noise, how would you even know? My Blackberry does this when I dial 9-1-1 to report an overturned vehicle in the #3 lane of the 210 Westbound at Sunland, but it sure couldn't tell me that LA County is calling or SMS'ing me a warning about Mothra attacking downtown.

But it's important NOT to discount SMS as a possible avenue of emergency notification. During the recent 5.2 earthquake here in the San Gabriel Valley, all the phone lines were busy--everyone from Covina to the Mexican Border was calling everyone else to see if they were OK. The only way I could get an "I'm ok" message back home was via SMS, which is of course far more bandwidth-efficient than voice conversations. This happened during the 9/11/01 response, too. So, the big questions: Can "Critical SMS" be engineered into the network? Should it be? Should there be statutory support for such a direction? Would the FCC support it? Should we encourage them to?

Alternative #2 is a <i>de facto</i> approach, like that of Aeris, but unless they get 100% carrier acceptance and handset code support, it'll (of course) be for their customers only.

Alternative #3, the "peer to peer" SMS chatter after a major emergency will continue, but (as Andy rightly points out) it's best-effort and wholly unreliable.

A side note: blaming FEMA for not jumping in to help in Katrina is somewhat incomplete. Many postmortems, from people with a right to an opinion, say that FEMA was standing by, ready to move in, if only Louisiana had said they needed it. (And they did, much earlier, in the other affected states.) Louisiana suffered administrative paralysis at the very top, and by statute FEMA must wait for a state request which was late by two days.

Not to say FEMA was blameless during Katrina--far from. Once they got moving, there was a great deal of wasted effort, lost opportunities and just plain bad management on their part. That certainly cost lives. But FEMA weren't the first responders, who must bear the brunt of the blame.

Unless FEMA is planning to usurp the role of the states, counties/parishes, and municipalities, and become the sole arbiter of what is Truly Worth SMS Notices, then early notification is still the right and responsibility of the locals. And if FEMA is truly trying to strip that right from the states and municipalities, there should be a national stink raised over it. (I can think of few people more suited to the task than Andy.)

--Alex Pournelle

P.S. I'm sure someone will try to start a flamewar about how I'm siding with the Feds on the Katrina response or something. Nope. People died because of the bungled response to the hurricane, and government at all levels must share the blame. But FEMA isn't a first responder organization, and can only respond if invited. You really wouldn't want it the other way 'round, would you?

If the FEMOids are trying to strip the right of the locals to use SMS as a notification tool, that is (in my opinion) a dangerous expansion of Federal powers--and would directly contravene their charter as NOT a first responder organization.

Stacey Black - 08/27/2008 11:25:39

Andy: AT&T and other carriers have understood the limitations of SMS for quite a while. SMS for emergency notification is a bad idea considering that a Standalone Dedicated Control Channel (SDCCH) channel can only process 15 SMS messages mer minute. A typcial cell sector can uses eight SDCCH channels which means the maximum message rate is 120 SMS miessages per minute. You do the math of trying to alert 30000 students in a campus served by a single sector. That is why messages sent under the recent Commercial Mobile Alert System (CMAS) that you reference will not use SMS as transport. AT&T along with other carriers participated in the CMAS advisory committee and jointly agreed to use Cell Broadcasting Service as the message transport. While the specifications exist, CBS is not deployed in the US and only in a few carrier's networks in Europe and will require new handsets. Since this is a multicast-type service (as opposed to unicast) this will eliminate the inherent delays of using SMS, For more information on this service, the FCC First Report and order on CMAS under FCC docket 08-99

For those local agencies that are concerned about being told what technology to use - SMS will still be available - but they need to be aware that delivery of messages is "best effort only" and subject to being caught in a spam filter.

Dallas KD4HNX - 08/27/2008 12:02:30

Stacey, Your math doesn't add up... A campus with 30K students will have multiple cell sites and multiple carriers... So your 120 per minute becomes 1200 per minute, maybe more... Some of the 30K students wil be off site... Hopefully the ones that get the message gasp, OMG their is XYZ going on and share the info with the folks around them... Not every person needs to get the message...

Chris Purpura - 08/27/2008 13:41:40

I won't argue math, but to say that not all carriers have implemented the same allocations for SDCCH channels, etc... Regardless of volume, latencies around consumer SMS is not reliable for mission-critical anything. We've done extensive drive testing over the last 3 years and found that even 2-4 test units sending an SMS every 2 miles experience large variances in latency between when they were sent and when they arrive. Think "long tail effect". We've tested all the major carriers side by side, along with our own network. The biggest variances seem to be whether the originative device is roaming outside it's home market (meaning a Verizon subscriber that might be in a Sprint market). It's pretty clear that these messages can travel through multiple routes, filters, gateways, etc...and in volume get very different levels of performance in terms of latency. These long tales, while in the <5% of total messages range, can take up to hours, days, weeks, and even "never". If we are taking consumer texting, it's probably acceptable (like dropped calls). If it's emergencies, airbag crash notifications, home alarms, seems obvious that this isn't acceptable. Where there is an interesting gray area is things like the Obama communication, or maybe more interesting are in some of the emerging products that use Cellular networks and SMS in particular to trigger functions. Imagine the Amazon Kindle that needs to be "woken up" by Amazon to open an EVDO connection to receive today's version of the NY Times. If they use SMS to wake up the device and establish an IP session, and that SMS shows up a Noon, nobody dies. But the consumer missed his morning paper, which reflects on Amazon's brand as well as the NY Times brand. Imagine an OnStar type service where a mom lock's her kid in the car and needs a remote door unlock. What's her impression if that doesn't happen right away? What is the impact on the brand image of her Auto OEM? There are many ideas out there for great new products and services to use SMS, but they just can't depend on it. I think this middle category of potential products is huge, but doesn't get the visibility of Obama and first responder type of examples. Regardless, thanks for a great topic Andy. It's a fun discussion.

Andrew Seybold - 08/27/2008 21:45:28

Great comments, and worth considering, and yes, Fred B it IS necessary to have a new phone (see Stacy's comments) in order to have one-to-many alerts. The bottom line for me is this:
1) An true emergency alerting system needs to be made up of many parts.
2) Guarenteed delivery for ALL notification systems
3) And understanding that even using every type of communications tehcnologies we are available to us, we are not going to be able to warn every single person in an affected area, the issue is to make sure that we alert as many as we can.

Frank Bulk - 09/01/2008 21:44:32

Stacey is right on the money here. Broadcast SMS is out there (read this article for an example: but it apparently hasn't been implemented by all operators.

FEMA and which ever other organizations are working together to put this alerting together ought to work together to make the the standards-based stuff work now, and work with manufacturers to make such SMS notifications obvious on the mobile devices (i.e. flash and ring and vibrate with special message on screen).