If your company requires guaranteed data communications to a WAN or the Internet, what have you installed for a back-up circuit?  Is it a second Internet or MPLS loop?  A different carrier or the same?  Is the back-up loop on a different geographical path?

When it comes to providing a secure secondary circuit, two alternatives that should be considered are:

• Microwave, which can provide >20Mbps of bandwidth, and
• Cellular routers using EVDO or HSUPA (600Kbps – 3Mbps)

In this blog posted, I’ll discuss cellular routers.

Cellular routers are a technology that is widely used in the retail and banking industry.  Surprisingly, IT professionals outside of these vertical markets are often unfamiliar with them.

In their simplest form, they provide a black-box with an Ethernet port to connect to your network and a cellular antenna jack to connect an antenna.  There is hardware available to use with any of the wireless service providers.  If they are used for back-up, there is no need for a $90/month unlimited data plan.

There are three approaches to installation:

• Install as a second Internet connection on your router, allowing your present router to handle all the routing.
• Install as the primary router, with your router connected to the cellular router WAN port.
• Install a Cisco HWIC GSM OR CDMA card with antenna in your Cisco router, although we don’t recommend this approach.

With either approach, the intent is that the wireless connection will ping the carrier network to keep this connection alive to allow fast roll-over if your primary circuit fails.  VRRP+ is used.

If you use this technology for a large number of sites, there are software tools to help you manage them.  The cellular carriers also offer pooled-data plans, which they never will tell you, to keep the monthly fees low.  There are also special back-up data plans that have low monthly fees with maximum fees not to exceed $125 for a month, to protect you on the upside.

The two technologies offered, EVDO and HSUPA differ as follows:

• EVDO is what you very likely use today with a wireless modem card in your laptop or on your Blackberry if you use Verizon or Sprint.  It’s benefit is relatively consistent speed as your distance from the cell-tower increases, or your field signal strength decreases.  Average speeds of 400-700Kbits/second are typical.
• HSUPA, or High-Speed Up-link Access is a new technology used by AT&T Wireless.  It has a theoretical up-link speed of 5.76 Mbit/second, depending on the device the user uses and carrier throttling efforts.  Unlike EVDO,  with HSUPA, your speed decreases rapidly as your field signal strength drops.

So what does it cost to install a cellular router?

• Pass-through device to install as second internet connection: $750.  This assumes that your present router can support the fail-over functionality.
• Device that supports BGP & VRRP for automatic fail-over, with built-in VPN hardware: $973
• Your monthly wireless fee: $30 to $75

If you would like to learn more about using a cellular router for your network, please contact the MPLS-Experts.

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