Sahana SMS Module – Thoughts and suggestions

I was invited by Lirneasia to a presentation on Sahana’s new SMS module yesterday. Lara’s live blogging of the event is available here. The module works well and looks nice and is particularly well suited for sending early warning messages to the disaster response network of Sarvodaya around Sri Lanka (there’s an acronym for this that I can’t remember). Scalability of the module to deal with a larger constituency (thousands of journalists and millions of citizens) is very suspect, but that’s not what it was designed for. As was explained to us, it’s also a problem of the sequential nature of sending SMSs out from the system.

But as was noted, no tests to date have been made on the actual performance of the system that for the moment runs on Dialog. My experience with SMS communications last year after a bombing close to home suggests that SMS is also prone to congestion that can last for hours, though a technical agreement with Dialog may possibly address this by prioritising message delivery for a specific set of numbers.

Cost was whatever the cost of sending an SMS within or through the Dialog network. It was clear that setting up this module needed to be done in consultation with (or at the very least, adequate notification given to) the mobile telecoms provider it used for message delivery. Else, as was pointed out, warning messages to hundreds could easily be shut down by automated SMS spam guards, which would defeat the purpose of the system.

One suggestion I had was to simplify their three character survey response code. My suggestion was to limit the characters to the first key press of a mobile keypad (a,d, g, j, m, p, t, w and *, 0 # if necessary) since multiple key presses to get to the other letters could lead to, particularly when also dealing with a chaotic context, high levels of stress and possibly sleep depravation, higher levels of error in input. 

The suggestion was also made to made the UI a bit more like Twitter, with notification of how many characters had been used in a message and how many there were left. 

It would also be necessary for Sahana to encourage the best practice of the most urgent numbers at the top of any group list, given the sequential nature of SMS delivery, ensuring that they got the message first. It would be useful then to also encourage the creation of groups based on geo-location – so that say in the case of a tsunami alert, disaster responders along the coastal belt most likely to be affected could be alerted as first and then others. Extrapolating key numbers from a group that contained a whole bunch of numbers at the time of sending the message out would be next to impossible. 

It would be interesting to see if the Government Information Dept. or National Disaster Management Centre takes this up as a means of communicating disaster early warning and subsequent information to journalists and other key actors. A key conversation in this regard was facilitated by an article of Chamath Ariyadasa from JNW news on Groundviews, well worth reading even today.

One feature I would like to see in the Sahana SMS module is an automated keyword response mechanism, akin to what FrontlineSMS already has. For example, someone in the field types “emc colombo” which could be a short-code understood by the system as a request for emergency contacts for that particular location / district / GN division. Those managing the module would be responsible for updating responses with current information. So in this example, “emc colombo” could result in as SMS like “N.D. Hettiarachchi,, +94112431590 T, +94112431593 F”.

It would be interesting if the system actually logged the delivery time of messages to the extent made possible by delivery receipts with Dialog and Mobitel (maybe with Tigo too). It would be interesting to get a a baseline on a normal day (a dry run of the system with Sarvodaya’s network) and another during an actual disaster warning / early response context to compare how the system deals with stress placed on it and on the larger mobile network. 

I wonder if Sahana can and will provide this module as a web service delinked from the larger Sahana system? I can see far broader applications for this than disaster early warning and a web services approach or at worst a thin client approach would allow it to be used by those who don’t necessarily want or need the full blown Sahana system. 

11 thoughts on “Sahana SMS Module – Thoughts and suggestions

  1. I want to emphasize that one should not run behind the chimera of an SMS system of early warning for the general population. Cannot be done. SMS is subject to congestion; no way to avoid it.

    The solution for that problem is cell broadcasting. We are working with the Maldives authorities on ironing out the implementation and institutional bugs on CB.

    Thane hatiyatai ane. Different (appropriate) solutions for different problems. For early and reliable communication to first responders (closed user group), ahead of the hazard and the resultant wave of congestion: SMS. For warning the general population: congestion-free cell broadcasting (in countries like Maldives where penetration is very high).

  2. It should be noted that the SMS messaging module described here was created specifically for the Sahana disaster management system with a CLOSED-USER group in mind. This means, that it is not ideal nor recommended for use for mass SMS alerts. Indeed, I too would consider that suspect. That was clarified in yesterday’s colloquium. Dialog Telekom is aware of the development of this system as GSM modems have been purchased for this particular purpose. This SMS module system does log messages sent and received within the Sahana system, and it was also mentioned that these messages (in a Google email-type format) would never be deleted, but archived for future reference.

    It would be useful for the government/DMC if it were to be picked up and used so that it could notify media/first responders rather than having to deal with countless calls asking about the status of an impending disaster. But that is up to government, for now, the idea is that this will streamline hazard alert dissemination within the closed-user group that is Sarvodaya.

  3. Rohan,

    For the record, I think your / Sarvodaya model of alerts sent to a closed set of persons who know what to do depending on the nature of the alert and importantly live in / deal with communities who are also trained in disaster preparedness and response is far better than SMS / media alerts to the general population which I think will just quickly lead to panic and chaos.

    Point is however that if the NDMC wishes to use this same module, they will quickly encounter the technical difficulties of sequential SMS delivery as opposed to CB unless they partner with every single mobile telco in Sri Lanka and are granted access to CB themselves. This I doubt will happen. So an SMS based alerting system for the general public I think will always be suspect from a SINGLE / CENTRAL node.

    There is another problem and it is that there is nothing to stop the SMS sent to the Sarvodaya network getting out to the public. My point is quite simply that early SMS parallelism (resulting out of users in the closed network forwarding SMS alerts to friends and family outside the closed group and so on) and the resulting congestion needs to be factored into early warning usage scenarios even if this system will only ever be used in / designed for a limited user group.


  4. Great article. We were also looking at having the functionality as a service: so that messaging can be done using web services and the likes: however, there are limitations, both procedural and technical, of using the currently sequential mechanism of sending SMSs. I guess that aspect needs to be clarified by the telcos: and it is very region specific as well.
    A service would be quite useful though: consider the many services available elsewhere, such as the SWN []. I see a service that allows for alerting via multiple media, duplicating the number of means a message has of reaching its recipient as a very useful application. Along with the idea of allowing for self subscription to various channels, of course…

  5. Mifan,

    Spot on. I also wonder whether some of the functionality of Txtmob ( can be integrated into a standalone package as it were of the SMS module. My interest here is to use it as a tool for the communications between and within communities on a range of issues and less on disaster early warning, which though subject to limitations, the system could also be used for.

    Also consider putting a unique user ID to each application along with a registration process for the app that asks for the user location. This allows a national level organisation, with the appropriate admin interface, to easily target specific installations in specific regions for messages, which can be very helpful. A bit like CB, but more low tech.

    Could you please explain a bit more the region specific nature of sequential SMS sending? Not sure I follow – do you mean to say that different countries and different telcos have different ways of prioritising the delivery of SMS messages?

    I know SWN well and have longed for a comparable service in SL since I read New York City’s alerting service that started early December last year.

    Keep me posted on further developments please and try to develop something along the lines I’ve suggest – this stuff is integral to the work I do in Sri Lanka and increasingly with the UN in NY.



  6. Sanjana,
    What I meant by region specific is the process of implementing such systems: some telcos and some countries allow users to implement mass SM services: with or without the support of the telco: sometimes as a profit-sharing model with the telco itself; whereas in some situations, it is quite difficult for a normal user/developer/organization to develop stuff themselves without the approval of the telcos: this also applies for Location Based Services and the likes.

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