Benefits of Layer 7 Load Balancing

Some time ago, I'm working with load balancer appliances where I have had to apply for the Radware Certified Application Specialist on Alteon (RCAS-AL) and the F5 Certified BIG-IP Administrator (F5-CA). Meanwhile, I have written some posts about Global Server Load Balancing and DNS Load Balancing and I have also had to reply about the benefits of a Layer 7 Load Balancing against the traditional Layer 4 Load Balancing. Therefore, I want to highlight in this post some advantages of this kind of load balancers.

First of all, it's important to know that if we want to install a layer 7 load balancer successfully we should have knowledge about networking and development because it is an appliance which is in the middle of the two worlds, networking for routing, nating, tagging, etc and development for load balancing applications. As a result, two teams should be in the installation and management of this kind of devices, the networking team and the development team.

The traditional layer 4 load balancer could load balancing applications based in TCP/UDP ports while the layer 7 load balancer is much more intelligent because it can make decisions based in the requests and responses of applications. For example, it can read HTTP headers for balancing by the User-Agent field, which could be useful for delivering a mobile web page to smartphones and the normal web page to computers or we can read the Accept-Language field to deliver the English web page to the English spoken people and the Spanish version to Spanish people. We can also read the URL/URI, allowing us to have an only public IP and many applications behind that IP, or we can even read de SSL ID, any data inside HTML files … all to make decisions, modify information, redirections, show messages, etc.

HTTP Headers
Other advantages of the layer 7 load balancing are the caching, compression and encrypting features which, if they are implemented properly and with hardware ASICs, can increase significantly the performance of applications. For example, we can manage all SSL certificates in an unique and centralized store inside the load balancer appliance and we can also configure SSL offloading to reduce CPU load in real servers.
SSL Offloading
A layer 7 load balancer is a full proxy which delivers better security, performance and adaptability than a traditional load balancer. For instance, they are able to block DDoS Attacks, SQLi and XSS Attacks analysing TCP sessions, HTML and XML files. On the other hand, better performance is delivered through the modification and configuration of the TCP stack like the TCP Express by F5 Networks, and we'll get better adaptability through scripts and APIs like iRules by F5 Networks.

Full Proxy Security
Last, but not less important, this kind of appliances can able to accelerate applications through new protocols and standards like Multipath TCP and HTTP/2. In addition, we can even deliver our services in a high availability worldwide through GSLB. As always, everything depend of our necessity.

Global Server Load Balancing
Regards my friends, drop me a line with the first thing you are thinking and balance your load!!