With the increasing importance of the Internet in our life, the traffic on the Internet and the workload on the servers have been increasing drastically causing them to get overloaded. In order to get rid of the overloading problem of the server, a Virtual Server is one of the solutions.
The Linux Server is built on a cluster or the real servers. The other name for the Linux Virtual Server system is the load balancing server cluster. Virtual server can be implemented in three ways. There are three IP load-balancing techniques that exist together in the Linux Director as given below:
- Virtual Server via NAT
In this technique, all the request packets as well as the response packets are required to pass through the load balancer. From several internet services like the web service it is evident that the request packets are often short and response packets and they usually have large amount of data. The advantage of the this technique is that any operating system that supports TCP/IP protocol can be run by real servers, real servers can use private Internet addresses, and only an IP address is needed for the load balancer. The disadvantage is that the scalability is limited.
- Virtual Server via IP Tunneling
In this technique, requests are scheduled by the load balancer to the different real servers, which in turn reply, directly to the users. So, huge amount of requests are handled by the load balancer and it also schedules over 100 real servers, and it won’t be the bottleneck of the system. The IP tunneling feature is again used in order to build a virtual server having high performance.
- Virtual Server via Direct Routing
In this technique, the response packets can follow the clients by using separate network routes. They can greatly make the scalability of virtual server high.
