Layer 4 (L4) load balancers
Layer 4 (L4) load balancers are made to distribute the website's traffic between two different servers. They work on the L4 TCP/UDP connections and shuffle bytes between backends. This means that the load balancer doesn't know the specific details of the application that is being served. It could be HTTP or Redis, MongoDB or any other protocol.
To perform layer 4 load balance an layer four load balancer modifies the destination TCP port number and IP address of the source. These changes do not look at the content of the packets. They take the address information from the first few TCP connections and make routing decisions based upon this information. A loadbalancer layer 4 is usually a hardware device with proprietary software. It could also include specialized chips to execute NAT operations.
While there are many different kinds of load balancers on the market, it is important to be aware that layer 7 and L4 load balancers have a connection to the OSI reference model. An L4 loadbalancer manages transactions at the transport layer. It relies on the simplest information and an algorithm for load balancing for determining which servers to serve. These load balancers do not examine actual packet content instead, they map IP addresses to servers they have to serve.
L4-LBs work best for web applications that don't use large amounts of memory. They are more efficient and can scale up or down easily. They are not subject to TCP Congestion Control (TCP) which restricts the bandwidth of connections. This can be expensive for companies that rely on high-speed transfers of data. L4-LBs are best used on a small network.
Load balancers Layer 7 (L7)
In the last few years, the development of Layer 7 load balancers (L7) has seen a resurgence. This is in line with the rising trend towards microservices. As systems evolve and dynamic, it becomes increasingly difficult to manage networks that are inherently flawed. A typical L7 loadbalancer can support a variety of features related to these newer protocols. They include auto-scaling rate-limiting, as well as auto-scaling. These features enhance the performance and reliability web applications, increasing customer satisfaction and the return of IT investments.
The L4 and L7 load balancers work by the distribution of traffic in a round-robin or least-connections manner. They conduct multiple health checks on each node and direct traffic towards the node that is able provide this service. Both the L4 and L7 loadbalancers utilize the same protocol but the former is more secure. It supports DoS mitigation as well as a variety security features.
L7 loadbalers function at the application level and are not Layer 4 loadbalers. They route packets based on ports or destination and source IP addresses. They perform Network Address Translation (NAT) but they do not look at packets. However, Layer 7 load balancers, which act at the application level, take into account HTTP, TCP, and SSL session IDs in determining the route for each request. Various algorithms are used to determine the direction the request should be routed.
The OSI model recommends load balancing at two levels. The load balancing server balancers in L4 decide which traffic packets to route based on IP addresses. Because they don't scrutinize the packet's contents, L4 loadbalers only look at the IP address. They map IP addresses to servers. This is called Network Address Translation (NAT).
Layer 8 (L9) load balancers
Layer 8 (L9) load balancers are a great choice to balance loads within your network. These are physical devices that distribute traffic across multiple network servers. These devices, also called Layer 4-7 Routers provide a virtual server address to the outside world and forward client requests to the right real server. They are efficient and cost-effective however they are limited in capacity and flexibility.
A Layer 7 (L7) load balancer is an listener that receives requests on behalf of back-end pool and distributes them in accordance with policies. These policies rely on the information of the application to determine which pool will service a request. A load balancer from L7 allows application infrastructure to be customized to specific content. One pool can be designed for serving images, while another one can serve scripting languages on servers, and the third pool can handle static content.
A Layer 7 load balancer can be used to balance loads. This will prevent TCP/UDP passingthrough and allow for more complex delivery models. However, it is important to be aware that Layer 7 load balancers are not perfect. You should only use them if your web application can handle millions of requests per second.
If you'd like to stay clear of the cost of round-robin-balancing, you can make use of connections with the lowest activity. This method is more complicated than the previous one and is based upon the IP address of the client. It is more expensive than round-robin, and works better when there are numerous persistent connections to your site. This is an excellent method for websites that have users across the globe.
Load balancers Layer 10 (L1)
Load balancers can be described as physical appliances which distribute traffic among group network servers. They provide clients with an IP address that is virtual and then direct them to the correct real server. They aren't as flexible and capacity, and therefore can be costly. This is the most efficient way to increase traffic to your web servers.
L4-7 load balancers handle traffic by utilizing a set of network services. These load balancers operate between ISO layers 4-7 and offer communication and data storage services. L4 load balancers not only manage traffic , but also provide security features. Traffic is managed by the network layer, also called TCP/IP. A load balancer L4 manages traffic by creating TCP connections between clients and upstream servers.
Layer 3 and Layer 4 provide two different ways to manage traffic. Both of these methods utilize the transport layer to deliver segments. Layer 3 NAT converts private addresses to public addresses. This is a distinct feature from L4 which sends traffic to Droplets via their public IP address. While Layer 4 load balancers may be faster, they can become performance bottlenecks. However, IP Encapsulation and Maglev treat existing IP headers as the complete payload. In actual fact, Maglev is used by Google as an external layer 4 TCP/UDP load balancer.
Another kind of load balancer is called a server load balancer. It supports various protocols, including HTTPS and HTTPS. It also supports Layer 7 advanced routing, making it suitable to cloud load balancing-native networks. A load balancer server can also be cloud-native. It acts as a gateway for inbound network traffic and is compatible with many protocol protocols. It also can be used to support gRPC.
Layer 12 (L2) load balancers
L2 load balancers can be employed in combination with other network devices. They are usually hardware devices that announce their IP addresses to clients and use these address ranges to prioritize traffic. However the IP address of the backend server does not matter as long as it is still accessible. A Layer 4 load balancer is typically a dedicated hardware device that utilizes proprietary software. It may also make use of specialized chips for NAT operations.
Another type of network-based load balancing is Layer 7 load balance. This kind of load balancing is performed at the OSI model's application layer, which means that the protocols behind it might not be as complex. A Layer 7 load balancer, for example simply forwards network traffic to a server upstream, regardless of the content. Although it is faster and more secure than Layer 7 load balancing, it has some drawbacks.
A load balancer L2 can be a great tool for managing backend traffic, as well as being a centralized point for failure. It can be used to route traffic around overloaded or unreliable backends. Clients do not need be aware of which backend to choose and the load balancer is able to delegate name resolution to a suitable backend if necessary. The load balancer also has the ability to delegate name resolution via built-in libraries and established DNS/IP/ports location locations. This type of solution could be costly, but it is generally worth it. It reduces the chance of failure and load balancer server scale issues.
In addition to balancing the loads L2 load balancers may also incorporate security features, global server load balancing load balancing such as authentication and DoS mitigation. In addition, they must be configured in a way that allows them to operate correctly. This configuration is known as the "control plane." There are a variety of ways to implement this type of load-balancer. It is vital that companies choose a partner that has a track record in the industry.
