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The other day I took my one year old son on his first train ride. I knew that he would enjoy the short trip (just a couple of stops and back) and I wanted him to get the feeling of riding a train. While on the train I noticed a teenager text messaging on a phone.

I smiled to myself, thinking that here’s a teenager holding a Smartphone in hand on a train with a modern Wi-Fi enabled network with 3G coverage, and yet she’s still communicating via a 30 year old technology.

Text messaging, or as they call it in the professional language, Short Message Service (SMS) is a very basic form of communication between cellular devices. As opposed to emails or IMs, you don’t need to have a Smartphone with  3G/4G/Wi-Fi data connectivity to send or receive SMS, a standard old cellular phone with no data connectivity will do the job (some restrictions may apply with certain cellular plans, of course).

It’s ironic amid all the new technology how SMS is all around us in our everyday life. If you want to vote for your favorite artist on a TV show, you can do it via SMS, if you want to make a donation for disaster victims, you can just SMS the dollar amount and get charged on your cellular bill. I guess SMSing is so intuitive and convenient that it has lasted for the last 30 years and it’s here to stay.

Why am I telling you about something that you probably already know?

On the Cisco ISR G2 series (39xx, 29xx, 19xx and some models of the 8xx) you can add a 3G cellular data modem, and beyond of the obvious use of WAN connectivity redundancy, there are many cool features that come with that interface card. One of those cool features is enabling SMS capability to and from a router.

IT managers that buy the Cisco 3G eHWIC interface are usually buying it for the fast (up to 21Mbps download and up to 5.7Mbps upload) HSPA+ cellular WAN connectivity or as a WAN redundancy interface. But one of the many great features included with the eHWIC that they may not be aware of is SMSing.

When a router has a 3G interface, it is just like a regular cellular phone from the SMS point of view, it has a cellular telephone number that you get from the cellular provider and you can send or receive text messages to and from the router.

Ok, now that we know we can SMS the router from any standard cellular phone, the big question becomes: What can I text my router?? Can I text it to come to my house to watch the game on TV :-)? The answer is actually, yes, although I doubt if it will come.

The point is that you can send the router whatever text you want as long as you’ve pre-defined texts with the router and it knows what to do with them. All you need to do is to write (or use Cisco support to help you with that) an IOS Embedded Event Manager (EEM) script to make the router do what you want it to do. For a simple example, let’s say you want the router to reset, you can write a script that will look for the tag word “reset” and then tell the IOS to reload. The SMS that you will securely send from a pre-defined number, enforced by the caller screening feature, to the router can say “please reset” and the router will parse the body of the SMS and look for the tag word “reset.” When found it will send a “reload” command to the router’s IOS.

If you want to create a more “complicated” scenario, we can create an EEM script for QoS that will initiate QoS policies from remote via SMS.

Let’s picture this scenario: you’re an IT manager and you are out with your spouse on a romantic dinner for your anniversary. The restaurant is on a mountain that has a great view but no 3G/4G/Wi-Fi converge. Suddenly you get an SMS from your enterprise router triggered by a pre-configured EEM script that your network is 90% loaded. You know that the CEO has a Telepresence conference call with Japan later that night, which will be in danger given the current load. If you’ve pre-defined the router caller screening feature, all you’d have to do is reply to the SMS that you received from the router and tell it to “implement QoS policy 5” (or whatever you called it), and you can continue your evening and enjoy the food. You can even program the router to report back to you when it’s done.

Without the SMS option you would have to be connected via Smartphone, laptop, tablet, land line, or worse you could lose your job or have to cancel on dinner. (Personally, I’d rather go with the lose my job option over canceling an anniversary dinner ;-) ).

I guess that you get the idea by now, almost anything you can do on Cisco IOS you can create as an EEM script, and any EEM script can be triggered from regular SMS on a router with the 3G eHWIC interface card.

There you go, that’s my take on a very cool and feature-rich product. Almost hard to believe how many features and benefits you get out of such a small interface card. I find it amazing that most of the IT managers that I talked to are using this card “just” for the 3G data redundancy and WAN capabilities. For more information, visit the Cisco 3G eHWIC page. If you’ve used this feature before, I’d like to hear your comments. Enjoy!

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10 Comments.


  1. IF you like this post, please send a text msg to… :)

       12 likes

  2. please add a similar diagram that describe this feature

       0 likes

  3. Good read, very interesting and is a great option for extended monitoring.

       1 like

  4. Great atricle. Very interesting. Keep them coming….

       0 likes

  5. Very interesting, I didn’t know you can do that. It gives great new options to monitor and manage my network.

    BTW, did your son like the train ride :) ?

       0 likes

  6. I’m pretty sure that our IT managers are not aware of such capabilities!
    I’ll make sure to forward this article – thanks!

       0 likes

  7. I’ll check it our – thanks for the info!

       0 likes

  8. Fernando Blanco

    That´s a great feature and I´m sure it will help many network managers…

       0 likes

  9. güzel bir paylaşım teşekkürler

       2 likes

  10. Tracking state via SMS – it is really useful thing, but nobody knows whether you can manage via SMS?

       1 like

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