With the expansion of IoT, many device manufacturers are rushing to embed cellular connectivity into their solutions. Cellular module manufacturers have made the process of embedding a certified modem simple with single chip designs. This enables OEM’s to reduce the build cost, minimize the use of engineering resources and shorten the time for a new device to enter the market.
These branded cellular modem modules are FCC certified and in the US, there are specific modules built to work on the major cellular carriers AT&T, Sprint, T-Mobile, and Verizon.
Certified or Not?
There are already many benefits to implementing a device with embedded cellular. Users should be careful when selecting a cellular enabled device that is being marketed as “certified”. In reality, the cellular module itself may have gone through the certification process, but when the module is embedded it does not automatically transfer that certification to the complete solution. The device itself needs to be tested again to ensure it works in conjunction with the cellular module.
End to End Device Testing?
Unfortunately, the testing process is just as complicated, and varies between cellular carriers. While some carriers just require the use of certified modules, others require an extensive end-to-end device testing of the entire solution. These tests are very thorough to ensure the solution being implemented fits the standards of the carrier and that it works properly while connected to the network. In rare instances devices that are not properly certified could be disconnected from the network. Below are just a few of the carrier requirements
Evaluating Your Options
While there are many cellular solutions on the market, network administrators must do their due diligence during the evaluation process before rolling out onto their network infrastructure. This is critical in an out-of-band solution where the cellular connection is primarily used during a failure.
You should understand which cellular module is embedded in the device, to ensure it is compatible with your cellular carrier. Some resources are available on the carrier’s website, where they may publish a list of devices that have gone through the testing process.
All cellular enabled Opengear solutions are using certified modules and are carrier certified for VZW, AT&T and Sprint.
Cellular is increasingly being adopted as a reliable failover strategy of last resort for network infrastructure. But what if your data center is underground and/or loaded with high-density devices that emit interference that results in poor signal strength or signal interference? It’s vital that you have a way to check your signal strength using a Web or command line interface (CLI) to make sure that in the event of a cellular failover your devices remain connected to a network. Here are some strategies for doing that.
Why Cellular Rocks as a Failover Option
First, a little shout out for cellular failover. A cellular connection is a fraction of the cost of a WAN interface or PSTN connection. (Check out this calculator to see the ROI of using cellular over POTS.) 4G LTE provides speeds up to 1000 times faster than a 56K modem. 5G will be even faster. So it’s no wonder that data center and Internet of Things (IoT) device developers are gravitating to the use of cellular as a second or third level of failover.
But what do you do if your deployment is in a basement, underground or in some other location or region with spotty coverage? How do you ensure a strong wireless signal?
Measure Signal Strength
First, measure the signal strength of your wireless connection and device. Received Signal Strength Indicator (RSSI) is a measurement of the radio frequency (RF) power present in a radio signal that is received by a mobile device. The best cellular throughput is achieved when a device and/or its antennas are positioned to maximize RSSI. The signal your phone receives from a cell tower is measured in decibel-milliwatts (dBm).
|69 dBm or less||Strong signal|
|89 to 70 dBm||Medium to high signal|
|99 to 90 dBm||Weak signal|
|100 dBm or more||Unacceptable signal (check antenna connection)|
Before measuring signal strength, configure your cellular connection to ensure that the readings you get are measuring the appropriate carrier and band. You do this through the Access Point Name (APN) gateway from your carrier’s cellular network to another network (usually the Internet or, by special arrangement with your carrier, to your private corporate network). The configured APN determines the IP address of your device.
Usually, configuring your cellular model only requires configuring the APN and adding a user name and password. (Verizon customers can leave the APN field blank as it’s automatically programmed.)
There are three ways to check signal strength. You can use a tool with a Web interface, a command line interface (CLI) or check it using the chassis LEDs.
If your device has signal strength LEDs, you can determine signal strength based on how many LEDs are lit. The LED status is updated every 5 seconds.
|4 LEDs lit||Strong signal|
|2 LEDs lit||Medium to high signal|
|1 LED lit||Weak signal|
|No LEDs lit||Unacceptable signal (check antenna connection)|
Using the CLI
Login to your CLI and type the following below to obtain a display cellular information
cellctl -l -s
Using a Web Interface
Using a management product with a Web-based user interface, you can look at the current state of the cellular modem, including RSSI.
Conducting a signal strength site survey before an installation is a very good idea. But you can do one at any time. Specialized equipment is available but a standard cellular phone with a SIM card from your carrier will typically allow you to check signal strength throughout your site.
The Right Antenna and Placement Are Key
If you are consistently receiving a poor or marginal signal using a standard antenna, consider a specialized high gain or directional antenna, an extender or a booster. Extenders or boosters enable you to capture signal away from the device, where poor or marginal signal strength can’t be remedied.
When placing antennas, first ensure that both Main and Aux antennas are properly connected. Make sure to place the antenna outside any metal racks and cabinets to avoid the Faraday cage effect, which blocks electromagnetic fields. Keep the antenna and cable away from AC wiring and other interference from other electrical or radio devices.
The optimum placement for an antenna is close to an exterior window or in a higher point in the building, such as on top of tall cabinets. Another factor to consider in antenna placement is the location of the carrier’s closest cell tower. Position it facing the tower if possible.
If All Else Fails…
If your signal strength still isn’t satisfactory, it might be time to look for another wireless carrier.
At Opengear we believe in giving our customers freedom of choice when it comes to wireless failover. That’s why our out-of-band (OOB) management consoles support pre-provisioning your wireless connection with dual SIMs, allowing you to test each carrier quickly and easily so you can choose the optimal carrier―the carrier that could be the difference between failover and downtime when all other network connections go down.
Cloud, IoT, M2M, failover, failback and security; a bunch of buzzwords that probably define the challenges you face today as a remote network administrator. You’re no longer sitting at the location ready to hop into action to fix problems. What makes the challenge even greater is the adoption of cloud based solutions taxing the network infrastructure, and becoming more dependent on internet connectivity to retrieve data. In retail markets these remote sites are even more critical since they are customer facing and are a revenue generating asset. They are becoming populated with increasingly complex POS systems, payment systems, advanced signage, data logging sensors and even guest network connectivity.
Unfortunately, many remote sites do not have the tools, on-site skills or the ability to react during a critical failure. Even sites deployed with failover connectivity are left at a severe disadvantage until they return to their normal operational status.
Is your backup connection up for the task of supporting your network? Your primary remote service relies on a physical connection typically provided by a cable company or a dedicated internet provider. Unless a redundant connection is available, building a new one can be cost prohibitive. One alternative is cellular connectivity that can provide a connection that is quicker and easier to deploy. In the United States, some cellular providers are offering connections up to 50 Mbps utilizing 4G LTE data. This is a vast improvement over 3G, which was only able to achieve 1/10th of that speed. Thus, many companies now rely on the cellular connectivity as a method of network failover.
In many instances, the speed and bandwidth provided by cellular is still insufficient to transmit the data being generated at the remote site. During peak hours, all the devices are trying to access the data at once, creating a backlog of traffic leaving your network at an unusable state. Imagine 5 lanes of traffic now merging onto a single lane. During this downtime, there could be a loss of sales, low productivity, and/or customer dissatisfaction – all of this affecting the bottom line. Can’t afford to have your remote site go down? Check out our eBook “Living on the Edge” here.
Recovery > failover
To manage the limited bandwidth, proper management tools are required on site to ensure that the most critical traffic is prioritized, leaving other parts of the network inactive during this period. The ability to recover or repair issues on site is a far more effective method than relying only on backup connectivity.
Management tools can generate notification of issues before they become failures, identify the problem remotely and possibly resolve simple issues with a restart. A hardware failure can be easily identified, and ensure that remote technicians traveling to the site are equipped with the correct parts for repair. And if a network connection is the reason for the failure, they can deploy difficult configurations to allow critical parts of the network to function while shutting others down.
Since employing network administrators at every single remote location is impractical, companies that deploy integrated advanced management tools have a competitive advantage by resolving issues faster, and bringing their networks back to their full operational state.
Businesses strive to be more agile to keep up with the competition and to meet ever-changing market demands. To keep up with the business, IT departments need to adapt to become leaner and more agile as well. On the networking side the drive for big data has put a strain on existing networks. The demand for larger data centers is increasing as well as a spread of these sites around the world.
Unfortunately, the deployment of data centers is still a slow and arduous process. In a traditional setup the networks were racked, powered and connected. After the hardware setup was complete, network administrators would come on site to deploy configurations into each individual device. This traditional model is still being used by many companies but a faster more agile way is available.
Day one is how we describe a brand new data center that has all the hardware physically installed but not configured and the network is not turned on or available. Coming on site is an option that could require network administrators to travel to remote areas for deployments. In colocation situations that additional time on site can be costly and limited as the company only rents the space.
An Opengear cellular out of band solution can give your network administrators the access as well as provide the connection necessary to access those devices on site. For example, a new site half way across the world can be prepared with all the necessary hardware setup by an outside vendor. Once the Opengear OOB management console is setup they can have full control of all the hardware at the site without ever setting foot on it.
Utilizing traditional OOB devices with POTS (modems) only allow a one to one connection. This severely limits the number of people working on deploying the network. In addition, with the slower data connections it also limits the ability to upload configurations or even upgrade firmware. Check out our new Cellular vs POTS calculator to find out how cellular has a better ROI.
One of the other benefits with utilizing Opengear for day one deployments is your network is completely setup for out of band management. The same critical devices connected via console are also the same ones that need management during failures. With our SmartOOB technology you can be sure your network will be resilient even if you are thousands of miles away.