Since this topic has come up several times over the last few weeks, I’ve decided to blog about creating custom report templates in Denika, our MRTG Performance Trender.

The first request was for monitoring Sensatronics temperature probes.  And then today we received the following request on our forums:

“Are there any way to make denika support mibs of ZTE or Huawei? Can i edit the template by some way, or some other method is available?”

And the answer is Yes, you can create new device and report templates with Denika. For Sensatronics, ZTE, Huawei, and other vendors also.  If they support SNMP, we can monitor them.  All you need is the IP Address, OID string, and the SNMP Credential for the device.
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OK, let’s say you’ve decided to live a healthier life. You’re exercising regularly, stopped getting drunk every night, and you’re eating healthy. You’ve been eating more salads, almost cut out red meat, and even eating annoyingly healthy desserts, if any. Read more »

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Yet again, it’s raining here in Maine. I think it has been raining for four days straight and now I’m beginning to get a little antsy to see some sunshine.

Usually, I don’t watch the Weather Channel. I just take every day as it comes and adapt to the weather. If I wake up and it’s rainy and cold, I wear something warmer. If it’s bright and sunny, I wear a t-shirt.
I’m simple that way.

But when we have a run in weather like this, I ask myself: “When is this going to end?!?”
That’s when I break out of my normal habit and check the forecast for the next couple days. I must admit, there is a sense of peace knowing that the rain SHOULD end by tomorrow night.

Much like monitoring the weather, you can use SNMP to monitor your daily, weekly or even monthly traffic statistics to help you project what tomorrow may bring.

Notice the Port Utilization graph shown above: Not only does it provide statistics based on current data collected, it also estimates future projections based on your current trend using those strike lines.

With limiting budgets, it’s more difficult to rationalize spending on a new DS3 circuit for the company. However, network performance monitoring applications, such as Denika, make life easy by forecasting network growth, so that you can see a problem before it ever begins.

Think about this: Would you feel better knowing that tomorrow was always going to be a bright and sunny day?

If you are not fortunate enough to have equipment that supports Cisco NetFlow technology, but still need to know bandwidth utilization statistics across network links, then there may be no better solution than the combination of SNMP and MRTG.

MRTG (or Multi Router Traffic Grapher) is a free software tool, developed by Tobias Oetiker, that uses SNMP (Simple Network Management Protocol) to poll network devices. MRTG stores the retrieved data to a log file, where it then generates a graphical representation of the stored data.

There are several third party network monitoring tools, like Denika, that use MRTG and SNMP as the means to capture this valuable data. In Denika’s case, the functionality of MRTG is expanded on by incorporating a MySQL database, which provides long term data storage.

If you have ever used MRTG, then you know that it is not easy to configure. MRTG uses a system of templates to send the neccessary object identifiers (OIDs) to the device, which then must have a MIB (or management information base).

Plixer has gone a long way to simplifying this process by making its database of MRTG templates available on the web. In Plixer’s MRTG repository, one can browse a number of different vendors, hardware models and templates. So whether you want to gather port utilization information on your Adtran devices, or frame relay utilization on your Cisco Catalyst 6509, or maybe just CPU utilization on your Foundry BigIron switch, it’s much easier to configure MRTG using Plixer’s MRTG repository.

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MRTG is a Multi Router Traffic Grapher that monitors network traffic and provides a live images of your network traffic.

The way MRTG works, as described by Wikipedia, is “MRTG uses the Simple Network Management Protocol (SNMP) to send requests with two object identifiers (OIDs) to a device. The device, which must be SNMP-enabled, will have a management information base (MIB) to look up the OIDs specified. After collecting the information it will send back the raw data encapsulated in an SNMP protocol. MRTG records this data in a log on the client along with previously recorded data for the device. The software then creates an HTML document from the logs, containing a list of graphs detailing traffic for the selected device.”

Plixer International has a variety or software that monitors network traffic.  Denika users MRTG report when monitoring and trending bandwidth usage.  It provides historical trends and real-time information on the status of network devices.  The most common use is bandwidth utilization.  However, it can be used to trend CPU, memory, hard drive space, sysUpTime, and any other SNMP OID; including non-SNMP variables (e.g. script monitoring for database activity). There is also a free Denika download.

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“What is going on here? It’s freezing!” is something I seem to hear here from time to time.  My friends who sit directly under the air vents have been saying the vents blow very cold air for a few minutes, then warm, then cold etc.  On the bright side they seem to stay warm from the activity of putting on and taking off their coats through out the day.  It’s all fun and games until I have to put my coat on.  Time to get to business…

Ironically, when the maintenance guy who we call KennyG shows up to check it out it, it miraculously warms up.  We know we have a problem because we’ve “temperature lasered” the vents and found that they were about 55 degrees.  What we need is cold hard proof, so why not score points for style while we’re at it?

We decided we were going to shove an SNMP temperature sensor in the air vent and graph the temperature with Denika so that we can show KennyG what really is going on here and when.  Ravica offers Bitsights, which are really cool little environmental probes that we use to monitor our server room’s temperature and humidity.

It turns out the temperature swings are pretty substantial, and probably shouldn’t be blowing air that cold in the first place.   KennyG now has the information that he needs to do whatever KennyG does and hopefully the need to wear our jackets inside will be a thing of the Christmas past.

So, if your maintenance guy isn’t working too hard on solving your problem with the HVAC, tell him to go shove a temperature sensor in the vent.

Merry Christmas,

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