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Network load balancing for businesses
Network load balancing (NLB) is a set of technologies that help business applications, services, and networks share traffic intelligently across multiple pathways.
It works at every level, from within applications and local networks to wide-area connections and globally distributed data centres.
In this guide, we break down the main types of load balancing by scale, explain how each one works, what it’s used for, and share real-world business examples.
Contents:
- What is network load balancing (NLB)?
- How does network load balancing work?
- Types of network load balancing
- Load balancing algorithms
What is network load balancing (NLB)?
Network Load Balancing (NLB) refers to a set of techniques used to improve network performance, reliability, and resilience by distributing traffic across multiple network paths.
It’s applied to a wide range of business applications at multiple scales, from apps and local networks to global networks. Common areas where load balancing is applied include:
- Multiple broadband connections: Leased lines, 5G, Starlink.
- Multiple LAN links: Ethernet CAT cables, wireless access points
- Multiple WAN links: Business Ethernet, MPLS, VPN tunnels
- Multiple cloud endpoints or servers: AWS Network Load Balancer, Load balancing within the data centre.
- Globally-distributed data centres: DNS based geo-routing.
Load balancing optimises traffic across these connections, helping ensure services stay fast, stable, and resilient.
Interestingly, recent improvements in load balancing techniques (e.g., software defined controllers and AI) have significantly enhanced the performance of online services.
Businesses use load balancing to improve connectivity, from VoIP communications and file transfers at the office, to global access to cloud services 24/7.
How does network load balancing work?
At its core, Network Load Balancing (NLB) intelligently directs traffic across multiple available paths to maximise performance and reliability.
It can be applied across networks of all sizes, handling various types of traffic under different rules and conditions, utilising both physical and virtual pathways.
However, each type of load balancing works differently, so we’ll look at how each one operates in the sections that follow.
Types of network load balancing
Network Load Balancing (NLB) can be categorised in several practical ways. The simplest approach, and the most useful for business decision-makers, is by scale.
We begin with how load balancing occurs within applications and servers, then move outward to the local area network (LAN), the business wide area network (WAN), and finally, global-scale enterprise infrastructure.
These layers often overlap in practice, and many businesses utilise load balancing at multiple scales to meet various needs.
💡 Note: While we group load balancing by scale here for clarity, IT professionals often classify it by OSI layer (e.g. Layer 4 vs Layer 7), load balancing algorithm (e.g. round robin, least connections), or deployment model (hardware, software, or cloud).
Application-level load balancing
Application-level load balancing operates within apps, microservices, and APIs. It distributes traffic based on request data such as URL paths, HTTP headers, or cookies.
This approach ensures apps remain responsive and resilient, especially under high traffic loads. Most businesses don’t need to manage it directly, as it’s built into services from cloud and app providers. However, for companies developing their digital platforms, it’s essential.
Who it’s for
Businesses hosting their own customer-facing portals, APIs, or internal applications.
Who it’s not for
Most small and local businesses. Those using off-the-shelf cloud apps (e.g. Microsoft 365, Salesforce, Shopify) with no need for infrastructure control.
Deployment
Software only. Deployed within web servers, reverse proxies, containers, or service mesh platforms.
Pathways
Application-level load balancing is typically implemented using:
- Service meshes: Internal routing between microservices (e.g. with Istio, Linkerd).
- API gateways or proxies: Routing traffic to backend services based on request data (e.g. NGINX, Envoy, HAProxy).
- Container platforms: Built-in routing within systems like Kubernetes using Ingress controllers.
How it works
User traffic reaches an application front end such as a website, API gateway, or reverse proxy, and is routed to the appropriate service or container instance based on:
- Type of request (e.g. /login, /checkout)
- Server load or instance health
- Application-specific rules (e.g. A/B testing, version targeting)
This allows granular control over performance, scaling, and resilience.
Business examples
Customer portals: An e-commerce company running its own platform routes traffic between login, product, and payment microservices.
APIs: A SaaS provider offering ID verification routes API calls across several back-end services to handle regional demand and traffic spikes.
LAN load balancing
LAN load balancing distributes traffic across internal resources within a single site, such as an office, warehouse, or branch, to improve local performance and add resilience for on-site services and devices.
Who it’s for
Businesses with critical on-site infrastructure such as office servers, internal apps, or a business VoIP phone system.
Who it’s not for
Cloud-only or fully remote businesses with no local network infrastructure.
Deployment
Primarily hardware-based. Managed through network switches, routers, and wireless access points, with some software tools used for internal services.
Pathways
LAN load balancing manages traffic across:
- Ethernet links: Combining multiple wired connections between switches and servers (e.g. using LACP).
- Wi-Fi access points: Distributing wireless client connections using mesh networks or controller-based systems.
- Internal servers or gateways: Spreading requests across redundant on-premises devices or service interfaces.
How it works
Embedded network controllers and protocols handle local load balancing decisions. These ensure local redundancy and prevent bottlenecks that could degrade performance.
Key technologies include:
- LACP (Link Aggregation Control Protocol): Combines Ethernet links into one logical channel for greater throughput and failover
- Wi-Fi controllers or mesh systems: Optimise client access based on signal strength, load, and performance (e.g. Cisco Meraki, Ubiquiti, Aruba)
- VLANs and QoS policies: Prioritise traffic types (e.g. VoIP traffic vs general data) for performance and security.
Business examples
- Multiple access points: A retail shop balances Wi-Fi traffic across mesh-connected access points to avoid congestion.
- Critical servers: A business uses LACP to increase bandwidth and redundancy between core switches and on-site servers.
- VoIP prioritisation: A call centre uses VLANs and QoS to ensure voice traffic isn’t disrupted by downloads or internal data use.
Broadband load balancing
Broadband load balancing distributes traffic across multiple internet connections to maintain performance and reliability at a site (e.g. an office, clinic, or industrial facility).
It’s particularly useful for managing outbound traffic and ensuring uptime.
This setup typically uses a multi-WAN router and controller to combine lines into a single logical connection.
Who it’s for
Businesses with multiple internet connections or those reliant on cloud apps, VoIP, or remote work.
Who it’s not for
Single-connection setups or micro businesses with minimal uptime needs.
Deployment
Hardware-based. Managed via routers or firewalls that support multi-WAN or business broadband failover functionality.
Pathways
Broadband load balancing is implemented using various UK business connection types:
- Leased line broadband: Highest performance line with fully dedicated bandwidth, often exceeding 1Gbps. Can be adapted into a Point-to-point Ethernet line for site-to-site communication.
- Full fibre business broadband: Shared (contended) fibre, typically sufficient for small business broadband needs or used as a secondary link in a load-balanced setup.
- Wireless leased line: Dedicated high-performance option for rural or underserved areas. Often used as a primary or failover line where fibre isn’t available.
- 5G business broadband: High-speed wireless connection with variable performance. Commonly used for broadband redundancy.
- Business satellite broadband: Offers nationwide coverage and is increasingly used for backup connectivity in load balancing configurations.
- Cable broadband: High-throughput but higher-latency connection, suitable as a secondary or failover line.
- SoGEA: Low-cost, lower-performance options ideal for small business failover or load balancing for businesses in rural areas.
How it works
Routing decisions for the broadband links are made by the router or firewall, and in larger setups, managed via SD-WAN.
These systems monitor connection health in real time and distribute traffic according to set policies:
- Static policies: Assign traffic by type or source, for example, routing VoIP over fibre and web browsing over 5G.
- Dynamic balancing: More advanced routers and SD-WAN analyses metrics such as latency, jitter, and packet loss to automatically choose the best path.
- Failover: Automatically switches to a backup link if a primary connection drops.
This enables high uptime, even load distribution and traffic prioritisation for important traffic.
Business examples
Here are some real-life examples of broadband load balancing:
- Fibre + 5G backup: An office uses 5G to stay online during fibre outages.
- VoIP prioritisation: A company dedicates its leased line to voice traffic, using a second connection for guest WiFi and general internet.
- Retail branch setup: A shop uses cable broadband for guest WiFi and satellite broadband for point-of-sale systems.
Wide Area Network (WAN) load balancing
WAN load balancing distributes traffic across multiple wide area network links connecting various business assets like sites, cloud apps and remote users.
Who it’s for
Businesses with multiple offices, remote sites, data centres, or cloud services need stable and optimised communication across locations.
Who it’s not for
Single-site or micro businesses without critical connectivity needs.
Deployment
Both software and hardware, typically via SD-WAN platforms or enterprise-grade edge devices like routers and firewalls.
Pathways
WAN load balancing is applied across:
- Business Ethernet and MPLS links: High-speed, low-latency circuits for connecting sites across cities, countries, or continents.
- VPN tunnels: Secure pathways over public internet connections, used for site-to-site routing, remote access, and cloud integration.
- Private backbone links: High-performance networks provided by cloud-native WAN or SASE providers for long-distance WANs.
- Dark fibre: Privately operated links offering full control and maximum privacy between critical sites.
How it works
Edge devices managed on-site, or centrally via SD-WAN, distribute traffic across a combination of WAN links.
Rules may be static, assigning specific applications or destinations to particular links, or dynamic, where SD-WAN automatically routes traffic based on live link conditions such as bandwidth, latency, jitter, and packet loss.
This ensures high availability, optimal performance, and resilient connectivity between distributed business assets.
Modern WAN load balancing extends beyond office-to-office communication. It supports remote users, mobile teams, IoT networks, and cloud platforms, all managed under centralised SD-WAN solutions with integrated security.
This achieves:
- Even traffic distribution: Balancing WAN traffic across multiple links (e.g. MPLS + VPN) to avoid bottlenecks.
- Optimised routing: Dynamic path selection for critical traffic such as VoIP or financial systems, based on real-time link performance.
- Failover: Automatic rerouting of traffic if a primary WAN connection fails or degrades.
Business examples
Here are some real-life examples of WAN load balancing:
- Multi-branch network: A retailer balances traffic between MPLS and VPN connections to maintain fast, resilient access across locations.
- Remote workers: A national company delivers secure, high-quality access to both cloud and on-site systems via SD-WAN.
- Remote site backup: A construction firm uses leased lines for transferring CAD files and a 4G link for background updates.
Geo-based load balancing
Geo-based (or global) load balancing distributes user traffic across servers, data centres, or cloud regions in different parts of the world.
It directs each user request to the most appropriate hosting location based on geography (IP), server health, or traffic load, instead of routing all traffic to a central host.
Typical use cases include multi-region hosting for e-commerce platforms, SaaS applications, or regulatory-compliant data access.
Who it’s for
Businesses serving global customers, operating across regions, or hosting applications in multiple data centres or cloud regions.
Who it’s not for
Local businesses with no international user base, limited online services, or centralised hosting.
Deployment
Primarily software-based, delivered via cloud platforms, DNS providers, or application delivery controllers (ADCs).
Pathways
Global load balancing distributes traffic across the following infrastructure:
- Multiple cloud regions: For example, directing traffic between AWS regions in London, Frankfurt, and Singapore.
- International data centres: Routing traffic between on-premises or co-located data centres in different countries.
- Edge networks or CDNs: Using services like Cloudflare to route and serve traffic closer to the end user.
- DNS-based systems: Directing users to different IPs based on geographic location or service status.
How it works
Requests from users or customers around the world are analysed and routed in real time to the optimal service location, often via DNS or Anycast systems. These platforms take into account:
- Geographic distance to the user (IP address)
- Server or data centre health
- Current traffic load or response time
- Service-level policies (e.g. cybersecurity compliance or data residency rules)
Global load balancing is often delivered through cloud-native tools like AWS Route 53, Azure Traffic Manager, or Cloudflare Load Balancer, enabling:
- Performance optimisation: Directs users to the lowest-latency server or edge location for faster loading and responsiveness.
- Resilience and uptime: Redirects traffic away from failed or overloaded regions instantly, maintaining service continuity.
- Regional control: Enables traffic steering based on business, legal, or technical requirements (e.g. keeping EU traffic in the EU).
Business examples
Here are some real-life examples of global load balancing:
- SaaS provider: A software company serving users across Europe and Asia directs each customer to the closest available cloud region for lower latency.
- E-commerce platform: An online retailer routes traffic to data centres in different continents, with automatic failover to backup regions during outages.
- Streaming service: A media provider uses a CDN and global load balancer to deliver video content from the nearest edge node to minimise buffering.
Network load balancing algorithms
Behind all load balancing are algorithms (i.e. rules that determine how traffic is distributed across available connections).
Different algorithms suit different business needs, depending on load balancing type, network setup, and performance goals.
Below is a list of the most commonly used load balancing algorithms, along with where they’re typically used and their advantages and disadvantages:
| Algorithm | How it works | Pros | Cons |
|---|---|---|---|
| Round-Robin | Distributes traffic evenly across all connections in sequence. | Simplest setup. | Not optimised for performance. |
| Weighted Round-Robin | Routes more traffic to higher-capacity or faster connections. | Accounts for varying connection speeds, improves performance for critical tasks. | Requires accurate configuration of weights and manual updates when conditions change. |
| Least Connections | Sends traffic to the connection with the fewest active sessions. | Keeps connections free for heavy loads, good for dynamic traffic. | May overload fast connections if idle links are slower but underused. |
| Weighted Least Connections | Similar to least connections but prioritises stronger connections. | Optimises heavy traffic based on connection strength. | Requires configuration and may not always be the most efficient if the load fluctuates rapidly. |
| Source IP Hash | Routes traffic based on the user’s IP, keeping the same IP on the same connection. | Ensures session persistence, useful for services that require continuity. | Less efficient for distributing traffic evenly, might overload a single connection. |
| Application-Based Routing | Directs traffic based on the type of application (e.g. VoIP, video, browsing etc.) | Prioritises critical business applications like VoIP or video, improving reliability and performance. | Requires detailed configuration and may not fully utilise all available bandwidth. |
| Weighted Bandwidth | Allocates traffic based on the available bandwidth of each connection. | Makes optimal use of faster connections for high-bandwidth tasks. | Slow connections may be under-utilised, leaving capacity unused. |
| Dynamic Load Balancing | Adjusts traffic routing in real-time based on current connection performance. | Automatically adapts to real-time network changes, optimising traffic at all times. | More complex and requires advanced hardware; may be overkill for simpler networks. |
Network load balancing – Frequently Asked Questions (FAQs)
Our business broadband experts answer commonly asked questions regarding network load balancing:
What is the difference between NLB and a regular router?
A standard router connects your local area network (LAN) to the internet via a single broadband connection.
Network load balancing (NLB, which includes broadband load balancing) distributes traffic across two or more internet connections.
This improves performance, resilience, and bandwidth usage, especially valuable for businesses with high or variable demand.
Do I need a dual WAN router for load balancing?
A multi-WAN router (often dual-WAN) is commonly used because it supports multiple broadband connections.
However, in SD-WAN deployments, multiple single-WAN edge routers can work together to balance traffic across locations intelligently.
Is load balancing worth it for small businesses?
Yes. Load balancing helps minimise downtime, improve connection reliability, and make better use of available bandwidth.
It’s especially valuable for small businesses that rely on UCaaS and other critical cloud services.
Can I balance broadband from different ISPs?
Using various business broadband providers for load balancing is actually recommended because it guarantees continued uptime even if one provider experiences issues.
Will VoIP or video calls improve with load balancing?
Yes. Real-time applications like VoIP and video calls can see noticeable improvements with effective load balancing across LAN, broadband, and WAN layers.
- On the LAN: Segmenting traffic using VLANs and smart switches helps prioritise voice and video, reducing local congestion.
- At the broadband level: Multi-WAN routers or SD-WAN can route traffic over the lowest-latency connections and failover to backup links if needed.
- At the WAN scale: Business-grade connectivity, such as MPLS, Ethernet, or dark fibre, provides more stable and lower-latency routes than traditional VPN tunnels, further enhancing call quality.
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