If you've ever been to a large music festival or sporting event with tens of thousands of people, all with something to say, gathering together in relatively small area, you'll probably be familiar with how hard it can be to get in touch with other people using a mobile phone.
"Getting a signal" can be a problem in rural areas, although many events are now sponsored by mobile phone companies who bring in additional cell towers to cope with sudden surge in demand.
If you can get a signal, getting a connection can be the next problem - mobile phone cell areas are limited in the number of concurrent connections they can support. Even sending SMS text messages can be problematic.
If you do manage to get a connection, it may take several minutes, or even hours, for the message to work its way through the various message queues it encounters until it reaches its destination.
We don't tend to help matters, of course. A common behaviour associated with failing to get a connection is to try call again. Immediately. This doesn't just apply to telephone communications - how many times have you tried to load a web page to see a "Connection timed out" or "Site is Down - Try Again Later", and then immediately tried to reload it?
For the connection server at the other end, the difficulties associated with trying to satisfy a sudden surge of connection requests is only compounded if, on failing to get a connection, users immediately try again. Reload, reload, RELOAD, RELOAD.
As the communication engineers would tell you, what we should really do is backoff, and then try again at random times selected from within increasingly long time windows.
Handling access control problems on networks and coming up with strategies for trying to avoid collisions between competing requests to access a network connection is a key issue for communication and network engineers. How to cope with this sort of challenge is one of the things that you might expect to learn about in the Open University course Communication and information technologies.
Planning communications capacity for known events is one thing, but even then, resource limitations may mean we can't satisfy everyone's needs at peak time in as timely a fashion as we'd like. But how much more demanding are things when disaster strikes?
In contrast to even a few years ago, where major news events came to popular attention through text ticker newsflashes interrupting regular television broadcasts, it was through the growing realtime international urban news network that is Twitter that I learned of the Boston marathon bombings (April, 2013).
My Twitter timeline, which includes updates from a significant numbers of both runners (I don't) and Americans (I'm not), was filled with retweets announcing the event.
At times like this - event related news bursts - it can be easy for "signal" to get lost in the noise of multiple retweets on a common theme; and even though I trust a lot of the people I follow not to post or retweet things that they don't trust, there's often little more story than speculation and same old news headline even amongst the unique updates.
No new information, in other words.
There are, however, story angles that can be picked out of a wider sample of updates (for example, updates "on topic" from people I don't follow). Twitter search tools can provide a stream of updates containing particular search terms, or from users within a particular geographical locale.
Journalists can also act as filters, using "beat" knowledge (and occasionally source verification) to filter the mass of updates and retweet those that they trust. The Guardian's technology editor, Charles Arthur (@charlesarthur on Twitter) is a good example. Several of Charles' retweets in particular caught my interest as someone interested in communication technologies, documenting as they did the dynamic communications environment around the emergency event. Here's the first retweet that caught my attention:
Worst thing people can do in emergencies is flood telephone lines. Use SMS (texting) to communicate so emergency responders can make calls
— Raymond Pritchett (@Galrahn) April 15, 2013
Although emergency services make use of radio communications on frequencies allocated, it makes sense to keep mobile phone traffic to a minimum to allow people who need to call the emergency services gain access to the network. Here's the next one:
— Nota Lemming #TGDN (@notalemming) April 15, 2013
What might justify such an action? According to the Associated Press, "A law enforcement official, citing an intelligence briefing, said cellphone service had been shut down Monday in the Boston area to prevent any potential remote detonations of explosives", although network operators denied this [Cellphone Use Heavy, but still operating in Boston].
As a "data sleuth", the sentiment behind this next retweet is one I shall take away and add to my data-sleuthing toolbox:
— WBTV_News (@WBTV_News) April 15, 2013
Which is to say: make use of data sources that may have been created around the event to track people participating in the event.
From news flashes and television dramas, we're probably all familiar with the idea of phoning helplines to help in tracking down particular individuals involved in emergencies; but we might also be able to help ourselves by looking for evidence that certain people have already left an event.
(Tracking people's locations via their mobile phones - with their permission, of course - is another way of doing this. Such facilities also exist through social network services, such as Google Latitude.)
How about this one?
If you're looking for some tiny good thing you could do from your desk right, now report these jackals for spam twitter.com/_BostonMarathon
— Josh Fruhlinger (@jfruh) April 15, 2013
Where there are people, there are spammers and pushers of malware. Hoax accounts can be created in seconds, have names likely to attract large numbers of followers in quick time, and can be used to send people to websites containing malicious software. Blocking such accounts and marking them as spam can help get them closed down.
As well as fake Twitter accounts, it seems that the incident became embedded in the fabric of the web by means of a variety of quickly and opportunistically registered domain names (this via is a retweet by @SamKinsley, 18 hours or so after the event):
— furtherfield (@furtherfield) April 16, 2013
Whereas bottlenecks tend to cause more blocking in on-the-ground communication networks as people repeatedly try to connect, some barriers to information are enforced "arbitrarily" (that is, limitations don't arise as a consequence of the "physics" of the technological system).
Like paywalls - financial barriers placed in the way of access to particular sources of information - or pay meters that track usage and levy charges, or page access limits, as a result. In emergencies, it seems, the paywalls may come down, at least on the breaking news pages...
The @nytimes is suspending the pay meter in wake of Boston explosions.
— Patrick LaForge, NYT (@palafo) April 15, 2013
Whilst access to the mobile phone network can quickly hit a limit when faced with a large surge in connection attempts, wired networks may be more resilient. With more and more mobile phones supporting WiFi access as well as connectivity to the mobile phone network, opening up channels to broadband network connections through the opening up of WiFi networks to allow unauthenticated access is one possibility:
If you’re a business in Boston, now would be a good time to unlock your Wi-Fi to help people connect with concerned family and friends.
— Roberto Baldwin (@strngwys) April 15, 2013
(In part this reminds me of RayNet, the UK Radio Amateurs' Emergency Network, a group of licensed radio amateurs who act as an additional "emergency infrastructure" service and set up ad hoc radio communications networks in the event of major incidents.)
One thing to beware of when using such open WiFi networks, of course, is the fact that the hotspot provider will be able to see all your internet traffic, and may set up an open WiFi network with the intention of stealing passwords or hijacking your online accounts.
Whilst I can well imagine many people around the vicinity of the event trying to get onto the web in order to look up local news sources to try to find out the cause of the chaos around them, I also wonder how many turned to "traditional" sources of broadcast news, such as radio stations. As radio industry commentator James Cridland observed,
... there are news reports that the cellular network was officially shut down for a time in Boston after the event, to ensure terrorists couldn't use the network for communications. Whether that's true, other reports from the scene do point to cellphones being unusable from sheer traffic on the networks for some time.
Even on wifi, the increase in demand for streaming produced issues. While WBZ isn't listed on TuneIn [an online service for listening to radio station feeds], WBUR is: but the signal quickly started buffering and became partially unavailable for me (from a fast UK network) around an hour after the event.
FM reception, of course, continued without incident. Broadcast radio is perfect to reach millions of people at the same time - and copes flawlessly with massive demand.
If you owned an FM-equipped smartphone in Boston yesterday, you'd have been able to get fast-breaking news and information that only radio can give.
If you had to rely on IP, you'd have had nothing: just when you needed it most. [Boston marathon: radio's future isn't just smartphone-shaped]
It seems that in the same way that different forms of media tend not to replace one another, but to complement each other - as the spoken word was added to by the written word; as television complemented radio - so too do different technological communications systems find - and retain - their own particular niche.
PS. Just as I was finishing this article, I came across a March 2013 report by the US Congressional Research Service on The First Responder Network and Next-Generation Communications for Public Safety: Issues for Congress. I wonder how a reading of that report will compare to the situations that were thrown up this most recent event?
If you would like to learn more about how communication networks have become embedded into today's world, why not check out the OpenLearn unit ICTs in everyday life? to learn how networked information communication technologies (ICTs) have come to play a pivotal role in our home, work and civic lives.