Tips for Implementing 4G for Internet Redundancy

Tips for Implementing 4G for Internet Redundancy

In today’s business reliable access to the internet is your lifeblood, without internet you won’t be able to send/receive emails and possibly be unable to process orders and run your normal operations, and if you running a phone system that’s using VoIP or SIP you will also be unable to take and receive calls which will not only annoy you and your staff, it will also prevent your customers from contacting you, which could possibly cause serious reputation damage to your brand.

Given the dependence on your internet connection, you may want to consider a ‘secondary’ internet connection, this secondary connection doesn’t need to be the same specs as your primary internet connection however, it needs to be capable of supporting your critical business operations.

One of the most cost-effective secondary connections available today would be mobile 4G, the same internet your mobile phones and tablets use, depending on the carrier 4G speeds can be as fast as 100 MBps and are very capable of supporting a handful of PC users and SIP/VoIP phones.

The real magic happens when you have a Router that supports automatic fail-over to 4G whenever your primary internet connection goes down, this will allow for a seamless transition to 4G without interrupting your users.

When choosing a 4G plan for use as a secondary connection, ensure that you understand how much data you consume during a month and ensure that you have enough 4G data for approx 1 week of usage, for example, if your using ADSL for a primary connection and the infrastructure and phone lines are damaged, depending on your carrier you may be without your ADSL service for several days.

When choosing a 4G service always ensure that you have good coverage with that carrier and ensure that the download/upload speeds are sufficient for your requirements. External antennas can be fitted which will dramatical increase 4G coverage, reliability and speed.

We recommend using a post-paid 4G service with a minimum of 1 GB of data each month that will automatically add more data as it’s needed, pre-paid services are also an option however ensure you understand when the pre-paid credit expires and once all the data has been consumed the service will stop working.


Test, test, test and make sure to add 4G fail-over testing to your DIY Maintenance register, regular testing will help you to feel confident that your 4G fail-over is working as expected and will help to identify any minor issues, some of the most common issues we see are “Routing” and “NAT” related issues.

  1. IP Addresses – In this article, we talk about External IPs which are “Real” IP’s that are accessible from the internet. And Internal IPs (in these scenarios they are sometimes referred to as NAT’d IPs), which are NOT accessible from the internet.
  2. Routing – is normally handled by your router or firewall (and your carriers) and is used to direct the data traffic to the correct location, routes can be static or dynamic depending on your setup.
  3. NAT – every device that uses the internet or a network, needs to have an IP address. Network-Address-Translation is a protocol used because there simply isn’t enough IP’s in the world to give every mobile device an external (internet) IP address, this protocol also creates a one-way bridge between the internet and your mobile device, that hides your mobile device from the internet.
    For example, you have a mobile phone that’s connected to the internet, you will see it has an IP address that has been assigned by your mobile carrier, this IP address isn’t the sort of normal IP address associated with an External IP addresses, and if you PING it from the Internet it won’t respond. Instead, this IP is an Internal IP address that belongs to your carrier’s Internal network and your carrier will route your traffic from the internet to your mobile device via their internal network.


Due to the nature of NAT, and the fact it’s controlled by your carrier, you want to ensure you test it regularly, some customer may experience issues with their carriers blocking specific traffic on the NAT or your carrier might change routes and IPs on their internal network which can break your 4G fail-over solution. One way around this is to use a VPN in combination with a Dynamic DNS service, this will force all traffic to a specific port (usually 443) which your carrier won’t block, and the dynamic DNS will keep track of your IP address in case it ever changes.


Check List

  1. Confirmed the need for a Secondary Internet connection to run your business?
  2. Confirmed if your Phone System uses your internet connection?
  3. Is Automatic Fail-over to 4G required?
  4. Confirmed how much Data you consume each month?
  5. Confirmed the 4G carrier has good coverage in your office?
  6. Confirmed if you need to install external 4G antennas to boost 4G reception?
  7. Added 4G Fail-over testing to the DIY Maintenance register?
  8. Tested and confirmed that you can route all your application traffic over 4G even when using your carriers NAT?
  9. Considered setting up a VPN and Dynamic DNS services for added reliability and security?

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