The WAN or Wide Area Network link is the weak link in this chain. If most computing is done locally or by downloading applications from an in-house server, you’ve got control of the system. You only lose your ability to communicate with the outside world when your link goes down. But lose that link on a cloud-based system and your client device becomes the proverbial doorstop -- one that's really too lightweight to make even a good doorstop. If everything you do is in the cloud, you’ve got to have a pathway to that cloud at all times.
Mobile device can get connection redundancy by having two wireless technologies embedded. The primary link is through the carrier’s data network that’s on the same towers used for cellular telephone service. You are more likely to encounter a weak signal area than for the carrier service to fail. But Hurricane Katrina taught us that even well designed wireless systems can go dark if the emergency is dire enough.
A commonly used second path is WiFi connectivity. WiFi has a couple of advantages. There’s almost always a WiFi hotspot, and usually a free one, within walking or driving distance. If the nearest hotspot is down because a line break has shut down all telecommunications in the area, you can simply venture out further until you find a place that’s connected to a different broadband service. It might be inconvenient, but at least you can get to your apps and data.
It’s not quite as easy to work around an outage in a bricks and mortar office or store. You can’t easily just have everybody pick up and move to the nearest coffee shop with service. Instead of depending on someone else for backup, you need to provide that redundancy yourself.
What makes a good backup service? A carbon copy of what you have now is better than nothing, but has limitations. For instance, if a nearby construction activity cuts the wire bundle containing your T1 line, it will likely cut through your second T1 line as well. In backing up T1 or DS3 connections, you want service from two separate suppliers that approach your building from different directions and have no wires or equipment in common. You may elect to set up your routers to use both lines normally but fall back to the single working line when failure occurs. That cuts your bandwidth in half, but everything else continues to work as usual.
You should think about what you need to get by during an emergency. Perhaps less bandwidth will slow things down but can be lived with for a short period of time. A T1 line makes a good backup for DS3 service despite the huge difference in bandwidth: 1.5 Mbps versus 45 Mbps. Since T1 is copper based and DS3 is fiber based, outages that affect one won’t necessarily take down the other.
You should also look at the newer Ethernet services for primary or backup bandwidth. An advantage of Ethernet is that it is often much lower cost per Mbps than traditional carrier grade services. It offers high reliability, and the lower speeds from 1 to 45 Mbps might be available over copper as well as fiber.
What’s the best backup service for your cloud based computing architecture? Check out the variety of bandwidth services available for your location.