The Complete Guide to 4G WAN

Posted by SAS on Jul 14, 2017 02:42:00 PM


Most IT teams know the challenge of keeping colleagues joined-up and information flowing during changes to their business, their buildings or their connectivity.

Sometimes you need to roll out connectivity in places where there’s little or no existing infrastructure. Sometimes you may need to restore connectivity in disaster situations. Occasionally you may need to join networks after a corporate merger.

What’s most important is that you do this quickly, reliably and with the minimum of fuss. You cannot afford to have your operations compromised because the impact on the business could be enormous, as well as creating great pressure on you and your team.

4G WAN technology is about ensuring that this never happens. Think of it as your enterprise-class connectivity-in-a-box, providing your workforce with instant access to your corporate network and the internet from the moment you turn it on – wherever, whenever. It’s robust and offers great quality without lengthy lead times.

The result? You can obtain reliable short-term connectivity before a fixed line is set up, respond to seasonal or temporary events, connect vehicles and tackle disaster situations.

In this guide, we’ll introduce you to this technology, helping you to understand how it works, the problems it solves and the questions you should be asking before you implement it.

Download our free guide for 4G WAN to learn how to create high speed, reliable, secure connections to your corporate network within days.

What is 4G WAN?

4G WAN leverages the mobile data network to provide you with a reliable, high speed connection through multiple 4G SIM cards from a mix of carriers.

The technology bonds these SIMs together into a single data connection and connects to your corporate network, the internet, or both.

This means you can:

  • Provide interim connectivity until permanent circuits are installed
  • Provide connections for temporary or seasonal events
  • Provide connectivity to mobile sites such as cars, buses, trains and boats
  • Achieve high-performance backup for your network that is diversely routed in the last mile
  • Connect sites that are prohibitively expensive to connect with fixed lines

The technology provides a flexible, robust and cost-effective alternative to fixed line circuits. In particular, it can be implemented extremely quickly.  Services such as FTTC can take weeks to implement.  Fibre Ethernet can take months, and frequently suffers unplanned delays associated with digging roads and pavements to lay fibre.  

Ultimately, 4G WAN keeps businesses digitally agile, with infrastructure that allows them to stay connected and respond quickly to scenarios they face.


What problems does it solve?

Because it can provide high speed, reliable connectivity extremely quickly, 4G WAN is extremely versatile and can help businesses that are:

  • Operating in locations with no existing infrastructure, such as those in the construction industry
  • Moving office, merging networks, or making planned changes to their infrastructure
  • Seeking a continuity solution to protect them in disaster situations
  • Looking for a backup solution that is diversely routed (ie. that won’t be destroyed by the same road digger that takes out the main circuit)
  • Using popup stands at events such as festivals, conferences and exhibitions
  • Looking for in-vehicle connectivity that can turn their fleet into mobile offices

Here are some of the main scenarios:

Delayed circuits

When ordering fixed network connectivity, you are at the mercy of lead times – which are often lengthy. When a site is opening at short notice, the lead time to get a circuit provisioned, installed and made live can impact the site opening date. This is made worse if circuits are unexpectedly delayed because of wayleave, traffic disruption or unexpected construction that needs to be undertaken and paid for.

By implementing 4G WAN, you can bypass these delays because the technology does not require any fixed connectivity at a new site. You get your site fully connected in a matter of days. This means that you can set up a reliable, high-speed connection into your network with no operational impact while a fixed line circuit is being installed.

Temporary locations

If you operate in temporary locations or frequently relocate sites, you’ll be met with the same issues and delays mentioned above. This is especially true if you operate construction sites, trade at festivals or exhibit at shows and events.

Some companies will only be at a given location for a matter of days, making fixed line connectivity illogical, while others will be on-site for months or possibly years and must face the lead times associated with getting fixed line connectivity up and running. In both cases, IT Managers need to provide connectivity to the site, but cannot have this impacting project deadlines. This leads to administrative challenges that occur not once, but again and again.

In both these scenarios, 4G WAN can remove these challenges and help you maintain reliable, high speed connectivity for temporary and movable sites, while simplifying administration.

Remote or costly circuits

If you have a remote site, or one with especially challenging circuit construction requirements, the cost of installing a fixed circuit can be prohibitive. This is often the case for remote site monitoring, security, entry systems, roadside sites and CCTV.

4G WAN can provide the connectivity needed without the need for heavy investment in construction costs.

Backup circuits and Disaster Recovery

With applications increasingly utilising the cloud, having a business continuity solution to keep users connected during a disaster is imperative. Some IT departments combat this by installing backup fixed connections, but these services don’t protect against an outage of the provider’s network, or fire and flood disrupting both primary and secondary fixed circuits..

4G WAN provides a high-performance solution to backup circuits, especially when you want to connect over a different route to improve resilience, and over a different network in case of provider outage. The technology can provide:

  • On-site cold standby for rapid, low-cost failover in the event of a main circuit outage
  • On-site hot standby for instant failover
  • Off-site standby, delivering a preconfigured router at short notice

Mobile deployments

Connecting a fleet of vehicles to your network allows the transfer of vital information between them and your business. You do this by deploying 4G WAN ‘in vehicle’, effectively turning your fleet into mobile offices. You can then connect these vehicles to your network, just as you would a standard ‘bricks and mortar’ office.

This enables your mobile workforce to enjoy connectivity to video and CCTV streaming, and GPS telematics through wireless hotspots. As well as automobile, 4G WAN is suitable for deployment into rail, emergency vehicles, bus and marine installations.

Key questions you should be asking yourself

  • Do you ever need new sites to be set up more quickly than fixed network circuits can be delivered?
  • How important is it to get these sites connected before they go live?
  • Are new sites ever delayed by wayleave or traffic management?
  • Do Excess Construction Charges (ECCs) ever impact your decision on a new circuit?
  • How are you providing resilience and diverse site connectivity currently?
  • Do you use mobile sites such as vehicles or boats? How do you connect these to your corporate network?
  • What’s the cost to your business of slow, unreliable connectivity? 


How does it work?

For best performance, you use multiple SIMs

  • Within a multi-SIM 4G router at your remote site

From multiple carriers

  • This delivers maximum performance in demanding (eg congested) environments
  • And provides additional resilience and diversity

To the internet or your corporate network

  • For connection to a corporate network, you set up a secure tunnel to a hub router
  • With onward connection to your WAN


Bonded Mobile Broadband 2v-01c


If your priority is to achieve the most stable, reliable, lossless connection, you would bond multiple 4G connections together into a single, reliable and connection that links into your corporate network or the internet.

The solution would then start with a hub router being installed in your Data Centre (or your Managed Service Provider’s (MSP’s) Data Centre, should you wish to use a hosted service). The hub allows multiple 4G connections to be bonded into a single, reliable, high performance connection with the lowest possible latency.

After that, a business grade multi-SIM 4G router is installed at each of your remote sites. If you’re using 4G WAN as a continuity solution, you’ll house these routers on-site for hot and cold standby, or off-site and ready for dispatch should you opt for an off-site standby setup.

Once both elements are set up, you set up a secure tunnel to your Data Centre, with onward connection to your WAN or the internet.

It is good practice to use multiple SIM cards from different mobile carriers.  This mitigates the risk of any one carrier having a poor signal or a congested cell.

If you don’t have time to install a hub, or perhaps if you don’t have latency-sensitive applications, you may choose to load balance the multiple SIMs instead of bonding them. Here, the router makes intelligent decisions about which channel to use for each conversation, based on intelligent algorithms such as lowest-latency.

It is not necessary to source the SIMs yourself.  In fact, it can be preferable to source them through a service provider, who can avoid the pain of managing SIMs and performance.   Some service providers will be able to provide a single bill for all the hardware, the SIMs and usage, which will make things far easier to manage. 

In theory it should be possible to deliver high speed, reliable connectivity within days using this technology.  This can be really valuable in the face of a connectivity disaster, where you need to connect sites temporarily, for example.  Some service providers will offer turnaround within these timescales (although you should check when the clock is started, and whether they can rent you a shared hub to get the fastest installation).

Commonly required options

The most common requirements we find people have when implementing 4G WAN are:

  • Wireless LAN access
  • Guest internet access
  • Internet breakout for corporate traffic (split tunnelling)


What do you need to set it up?

A 4G WAN solution is made up of four main components. Once these have been set up and configured, your connection will be available immediately.

  • Site routers
  • 4G SIMs from multiple carriers
  • An optional central hub if you are bonding (which is sited in your data centre or hosted on your behalf)
  • A management service

Your hub will be set up in your data centre (or your MSP may offer to host it in theirs).  The site routers need to be sent to site along with the SIMs, ready for set-up, configuration and importantly, tuning (which is best done by an engineer working with a Network Operations Centre).

A central hub

The central hub is what bonds the traffic from the SIMs at your sites. It can support multiple sites, and can be installed at multiple data centres if required, or hosted on your behalf.

A 4G router

Your 4G router is delivered to site together with your SIMs. The router provides the secure connection back to your central hub. We’ll highlight things to look out for in a router, later in this document. We generally specify 4G routers from industry-leading Peplink.


Multiple 4G SIMs are bonded to provide you with a single, high speed connection. For additional resilience and 100% coverage, you can bond SIMs from multiple mobile networks. However, you should avoid mixing 3G and 4G SIMs in the bond as the maximum performance of the network will be determined by the slowest connection – which will be the much slower 3G network in this situation.


This means that your department, and your chosen supplier, can monitor the performance of your solution 24/7 – giving you complete confidence and peace of mind.

All in one box

Since 4G WAN is so often required quickly, experienced suppliers will hold pre-configured routers, with SIMs and aerials ready to go.  They’ll have them boxed in appropriate containers because of the environments they’re commonly going to. They’ll usually also have a mix of aerial types to cope with the specific location that they’ll be going to.  The best providers will be able to have an engineer bring this to site and set it up for you within a couple of working days. 


Understanding 4G WAN concepts


Bonding and Load Balancing

There are a couple of ways to combine the traffic from multiple SIMs.  You can bond or you can load balance. Bonding involves combining each of the connections together into one, single, connection.  Load Balancing distributes traffic across a number of connections but keeps them separate.  

Bonding gives you reliability, because dropped packets can immediately be retransmitted.  It gives you great performance when connecting to your corporate network, because all of the channels can be used for the VPN and failover is instant when one channel has a problem.

Load Balancing can help if you want to prioritise local internet breakout performance and the ability to monitor quality of service parameters together.

We usually recommend bonding, but there are occasions when Load Balancing will work for you.  

You can read more in our post about Bonding vs Load Balancing >>, and in this one about 4G WAN: Design Considerations >>.


The Importance of latency

Latency refers to the delay involved in getting data to its destination across the network.  We generally time it as a round trip delay - to get information to its destination and back again.   Latency is usually measured in milliseconds (ms). Round trip delay is important because a computer that uses a TCP/IP network sends a limited amount of data to its destination and then waits for an acknowledgement to come back before sending any more. Thus, the round trip delay has a key impact on the performance of the network.

Why is latency important for a 4G WAN?   

Well, first, the latency of a 4G cellular data connection can be of the order of 60 milliseconds (ms).  This is greater than the best fixed line networks (such as an Ethernet VPN  that might have as little as 10ms latency).  Thus, you need to be mindful of latency-sensitive applications that you want to run over a 4G connection.

Secondly,  when you bond multiple connections, the overall latency tends towards that of the connection with greatest latency within the bond.  If one of your SIMs is only managing to establish a 3G connection, then that will have a detrimental effect on the performance.

You can find more detail in this post: What is network latency? >>


Managing 4G cost and usage

It’s important to think from the outset about measuring your data usage and controlling your costs. It doesn't need to be a huge problem, but it can become so if you aren't proactive.  There are a couple of different approaches to paying for your usage.

  • Bundles and packages are useful, if you know exactly how much your sites are using and expect little or no variation – but beware of excess usage charges;
  • Pay as you use offers a true reflection of what you use, billing you more accurately - but beware the resolution they use to measure the amount used;

If you use a service provider to deliver a 4G WAN solution, they should help evaluate your usage and make a recommendation. They should also be able to set you up with accurate usage reporting and alerts when limits are being reached, to help you control cost and reduce bill shock.

It can be tempting to obtain SIM cards yourself, but we have found that this often leads to problems down the line.  For example, if you obtain a SIM yourself and at some point it's usage breaches some fair usage policy (that may not be clear to you),  you may find that the connection stops working without notice.  Your initial inclination will be to ask the managed service provider to check why your service is slow (or stopped),  but they won't be able to help because the problem is with your part of the solution, and they won't have access to systems to identify that.    We find there are fewer problems when you get your SIMs as part of a service package from a service provider.

However,  there are lots of questions to ask them before you give them that role.  Here are just a few examples: 

  • Can you pool your usage across all the SIMs you use from a carrier? This can really help to lower cost costs. 
  • What’s the minimum term? It might be as little as one month, but watch out for longer contracts!
  • Does your managed service provider provide access to all the UK carriers? And International carriers?
  • If you exceed your bundled usage, what are the overage charges?

For more information, why not read our post: 4G WAN: Design Considerations >>

How to choose a 4G router

There are many 4G routers on the market, offering a wide variety of features. Here are the main questions you should ask when comparing 4G routers for your business. 

  • Does it support Multiple SIMs?
  • What is the SIM Capacity?
  • Does it support Bonding
  • Does it support Load Balancing
  • Does it support SIM Failover
  • Can it prioritise by traffic type?
  • Does it support Caching
  • Can it include other WAN interfaces
  • Does it offer WiFi access?
  • Can it act as a WiFi controller for larger installations with multiple WiFi access points?
  • Does it have a Modular Design (and do I need one)?
  • Does it support Power over Ethernet (POE)
  • Does it offer reporting?

Download our free guide to help you choose the right 4G router for your business.


How to choose a 4G service provider

4G WAN is non-trivial to set up really well, so many people opt for a service provider to do it for them. There is a wide range of services and capabilities available, so you will need to consider carefully the features and the service experience that best meet your needs.  Here are a few of the initial questions you might ask prospective service providers:

  • Can they connect into your Corporate WAN? 
  • Do they offer bonded multi-SIM, multi-carrier solutions?
  • Can they show experience and give customer references?
  • How quickly can they deploy? When do they start the clock when citing a time?
  • Can they migrate your 4G circuit to a fixed circuit once that becomes available?
  • Do they support specialist aerials for remote sites, portakabins etc?
  • Do they provide on-site cabling and WiFi that might also be required?

This is just a sample of the questions you should be asking.  

You can find more in our blog: 30 questions to ask a prospective 4G WAN provider


Rapid Site Deployment from SAS

Rapid Site Deployment (RSD) is SAS’ innovative 4G WAN service offering business grade performance and resilience for the most demanding applications via a bonded multi-SIM, multi-carrier solution. With RSD, your solution can be provisioned, on-site and active within as little as two days.  We can offer solutions to all the scenarios outlined within this guide.

A different approach

Unlike other MSPs, we bond multiple SIMs from multiple mobile operators. This gives reliable, high speed connections for critical applications. Alongside this, our service is fully-managed – giving you peace of mind and flexibility.

Our solution is designed to address key business challenges such as:

  • Temporary site deployment
  • Mobile and remote site connectivity
  • Resilience and diverse site connectivity

Download the Rapid Site Deployment Brochure to find out more.

How we work

Consult: We consult on the design that will achieve the best connectivity for each situation you need to address, drawing on expertise gained from many hundreds of deployments.

Design: We’ll design a solution to match your needs, combining the best hardware, network operators and data packages for each deployment.

Install & Configure: We will install and configure each of your sites to make sure you obtain optimum performance.

Support: We’ll provide year-round support for your solution, including monitoring and usage management, tailored to match the business-critical needs of your sites and applications.