Load balancers Layer 4 (L4)
Layer 4 (L4) load balancers are used to distribute web site traffic between two upstream servers. They operate at the L4 TCP/UDP connection level , and move bytes from one backend to the next. This means that the loadbalancer does not know the details of the application being served. It could be HTTP, Redis, MongoDB, or any other protocol.
Layer 4 load balancing happens by a loadbalancer for layer 4. This changes the destination TCP port numbers as well as the source IP addresses. The changeovers don't look at the contents of packets. They extract the address information from the initial TCP connections and make routing decisions based upon that information. A layer 4 loadbalancer is usually a hardware device with proprietary software. It could also include specialized chips that perform NAT operations.
While there are many different kinds of load balancers that are available, it is important to be aware that both L4 and layer 7 load balancers have a connection to the OSI reference model. The L4 load balancer controls transactions at the transport layer, and relies on basic information and a simple load balancing algorithm to decide which servers to serve. The primary difference between these load balancers is that they do not look at the actual content of the packet but instead assign IP addresses to the servers they must serve.
L4-LBs are ideal for websites that don't need much memory. They are more efficient and can scale up and down easily. They are not subject to TCP Congestion Control (TCP) which limits the speed of connections. However, this feature can be costly for cloud load balancing businesses that depend on high-speed transfer of data. This is why L4-LBs should be used on a small network.
Layer 7 (L7) load balancers
The development of Layer 7 (L7) load balancers has been regaining popularity in the last few years, and is a sign of the increasing trend towards microservice architectures. As systems become more dynamic, inherently faulty networks become more difficult to manage. A typical L7 load balancer supports several features associated with these more recent protocols, such as auto-scaling and rate limitation. These features enhance the efficiency and reliability of web-based applications, increasing customer satisfaction and the return on IT investments.
The L4 and L7 load balancers function by distributing traffic in a round-robin or least-connections style. They conduct multiple health checks on each node , and then direct traffic to the node able to provide this service. The L4 and L7 load balancers work with the same protocol, but the latter is considered to be more secure. It also supports a variety of security features, like DoS mitigation.
Contrary to Layer 4 load balancers, L7 load balancers operate at the application level. They route packets based on ports or destination and source IP addresses. They do Network Address Translation (NAT) but do not examine packets. However, Layer 7 load balancers that operate at the application level, consider HTTP, TCP, and SSL session IDs when determining the path to be taken for each request. There are many algorithms to determine where a request needs to go.
According to the OSI model load balancing must be done at two levels. IP addresses are used by L4 load balancers to determine the direction in which traffic packets should be routed. Since they don't look at the packet's content, load balancers of L4 only look at the IP address, and they don't examine the contents of the packet. They assign IP addresses to servers. This is called Network Address Translation (NAT).
Load balancers Layer 8 (L9)
Layer 8 (L9) load-balancing devices are the most effective for balancing loads within your network. They are physical devices that help distribute traffic among several servers in your network. These devices, also called Layer 4-7 Routers provide an address that is a virtual server to the world outside and forward clients' requests to the correct real server. They are affordable and powerful, but they have limited flexibility and performance.
A Layer 7 (L7) loadbalancer is a listener that takes requests from back-end pool pools and distributes them according to policies. These policies use information from the application to determine which pool will be able to handle the request. Additionally, an L7 load balancer allows the application infrastructure to be adapted to serve specific types of content. One pool can be optimized for serving images, while another pool is designed for serving server-side scripting languages and a third one can serve static content.
Utilizing the Layer 7 load balancer to balance loads will stop the use of TCP/UDP passthroughs and allow more complicated models of delivery. Be aware that Layer 7 loadbalancers may not be perfect. They should only be used if your web server load balancing application can handle millions of requests per second.
If you'd like to avoid the cost of round-robin balancing, it is possible to make use of connections with the lowest activity. This method is much more sophisticated than the former and is based on the IP address of the client. It is more expensive than round-robin, and is best suited for sites with many persistent connections to your site. This is a great option for websites with users across the globe.
Layer 10 (L1) load balancers
Load balancers can be described as physical appliances that distribute traffic across group network servers. They offer an IP address virtual to the outside world , and then direct clients' requests to the appropriate real server load balancing. They are limited in flexibility and load balancer server capacity, therefore they are expensive. This is the best way to boost traffic to your servers.
L4-7 load balancers manage traffic using a set of network services. These load balancers are operated between ISO layers four through seven and provide data and communication storage services. In addition to managing traffic, L4 load balancers offer security features. Traffic is managed by the network layer, which is known as TCP/IP. A load balancer L4 manages traffic by establishing TCP connections between clients and servers upstream.
Layer 3 and Layer 4 are two different methods of the balancing of traffic. Both approaches use the transport layer to deliver segments. Layer 3 NAT converts private addresses to public ones. This is a huge contrast to L4 which sends traffic through Droplets with a public IP address. Additionally, even though Layer 4 load balancers have a faster speed, they may become performance bottlenecks. Maglev and IP Encapsulation, however deal with existing IP headers as the complete payload. In reality, Maglev is used by Google as an external layer 4 TCP/UDP load balancer.
A server load balancer is another kind of load balancer. It supports different protocols, including HTTP and HTTPS. It also supports Layer 7 advanced routing features, making it compatible with cloud-native networks. A load balancer server is also a cloud-native option. It acts as a gateway for inbound network traffic and can be used with multiple protocol protocols. It also can be used to support gRPC.
Layer 12 (L2) load balancers
L2 loadbalancers are typically used in conjunction with other network devices. They are usually hardware devices that broadcast their IP addresses to clients and use these addresses to prioritize traffic. However the IP address of the backend server doesn't matter as long as it is still accessible. A Layer 4 loadbalancer is typically an exclusive hardware device that runs proprietary software load balancer. It can also employ specific chips to perform NAT operations.
Another type of network-based load balancers is Layer 7 load balance. This type of load balancer works at the layer of application in the OSI model, Load balancer server where the underlying protocols are not as advanced. For instance, a Layer 7 load balancer forwards network packets to an upstream server regardless of the content. While it may be faster and more secure than Layer 7 load balancers, it comes with a number of disadvantages.
In addition to serving as an uncentralized point of failure An L2 load balancer can be a great tool to manage backend traffic. It can be used to route traffic around bad or overloaded backends. Clients don't have to know which backend to choose. If needed the load balancer could delegate backend name resolution. The load balancer can also delegate name resolution through built-in libraries and known DNS/IP/port locations. This type of solution can be expensive, but is generally worth it. It eliminates the possibility of failure and scale issues.
L2 load balancers are capable of balancing loads, and also implementing security features such as authentication or DoS mitigation. In addition, they must be configured in a manner that allows them to operate correctly. This configuration is known as the "control plane". The process of implementing this type of load balancer might differ greatly. It is important that companies partner with a partner who has a track record in the field.
