Sending out SMS messages with SCOM

In order for SCOM to send out SMS messages a regular cellular phone needs to be attached to the RMS server. When this phone is being recognized by the server OS running on the RMS, SCOM is capable of sending out SMS messages.

Drawbacks:
However with this kind of setup there are some drawbacks to reckon with:

1. A cellular phone is a bit clunky and prone to hard- and software errors. So changes are the cellular will fail sooner or later;
2. A cellular phone attached to a server can invite certain administrators to use it for doing some private calls, so the RMS can no longer send out SMS messages;
3. When a RMS fails and a MS is promoted to RMS, it takes time to reconnect the mobile device to the new RMS. Many times people forget it;
4. A cellular phone requires software which is mostly written for desktops not for servers. Changes are likely new bugs are pumped into the server hosting the RMS role;
5. A cellular phone is an overkill: one only needs SMS capability nothing more, nothing less;
6. When the RMS is virtualized, how to go about connecting a cellular phone to that server?

So how to go about it? How to take care of these earlier mentioned drawbacks in such a way that one can send out SMS messages with SCOM and not being all to vulnerable? One can use internet solutions in order to send out SMS messages but that introduces new risks, many of which one can not influence at all. So another approach is required here.

The whole solution:
The solution is to be found in two pieces of hardware:

1. a SIM box;
2. a ‘translator’ of a serial connection over IP.

With the first mentioned solution one could do almost the trick and cover most earlier mentioned drawbacks. However, numbers 3 and 6 are still not covered for. Why? The SIM box needs to be directly attached to the RMS, using a serial connection. So when the RMS is virtualized, this cannot be done. Or when the RMS is physical and it fails, the new RMS (a promoted MS) cannot send out any SMS messages, only when the SIM box is attached to that server and the software is installed and properly configured.

In order to tackle number 3 and 6, the ‘translator’ comes into play. This solution connects on one site to the SIM box over a serial connection and translates it to an ordinary IP connection. When the software for this device is installed on the RMS it becomes ‘transparent’ and the RMS will be able to use the SIM Box as a modem using a ordinary LAN connection!

So the setup looks like this schematic drawing:

Explanation:

• The RMS is connected to the LAN;
• The Serial-Over-IP device (Digi One SP for instance) is connected to the LAN as well;
• The SIM Box (Siemens TC35i for instance) is connected to the Serial-Over-IP Device through a serial connection;
• On the RMS the software for the Serial-Over-IP Device is installed and configured (really easy);
• On the RMS a Modem is added, the Siemens TC35i is being used here.

This way all the earlier mentioned drawbacks have been covered. On the MS the software for the Digi One is easily installed. So when that MS is promoted to RMS, the Notification Model using SMS is also easily transferred to that server.

Another huge advantage of the SIM Box is its robustness. It is not easily wrecked nor used by a systems engineer looking for a cheap way to make a phone call…

Where to get what:
- SIM Box, like the Siemens TC35i;
- Serial-Over-IP, like the Digi One SP.

Special Credits:
Without the help and advice of Alexandre Verkinderen this posting could not have been written. So all credits go to him.