One of the greatest challenges to any organization is the maintaining of continuous and economical Web and application infrastructure and uptime. Business-critical Web sites and intranets face many challenges, from user traffic spikes to server bog down to handle compute-intensive SSL transactions, large and numerous data file requests and IO and memory overloads and hackers try to flood servers with malicious attacks.
The key components in dealing with increased and unpredictable Web traffic and enabling of high availability for both Web-facing and Internet applications is the application delivery and load balancing appliance.
Load balancing is the process by which inbound internet protocol (IP) traffic can be distributed across multiple servers. Load balancing enhances the performance of the servers, leads to their optimal utilization and ensures that no single server is overwhelmed. Load balancing is particularly important for busy networks, where it is difficult to predict the number of requests that will be issued to a server.
Typically, two or more web serves are employed in a load balancing scheme. In case one of the servers begins to get overloaded, the requests are forwarded to another server. Load balancing brings down the service time by allowing multiple servers to handle the requests. This service time is reduced by using a load balancer to identify which server has the appropriate availability to receive the traffic.
The IT infrastructure is playing an increasingly important role in the success of a business. Market share, customer satisfaction and company image are all intertwined with the consistent availability of a company’s web site. Network servers are now frequently used to host ERP, e-commerce and a myriad of other applications. The foundation of these sites – the e-business infrastructure – is expected to provide high performance, high availability, and secure and scalable solutions to support all applications at all times.
However, the availability of these applications is often threatened by network overloads as well as server and application failures. Resource utilization is often out of balance, resulting in the low-performance resources being overloaded with requests while the high-performance resources remain idle. Server load balancing is a widely adopted solution to performance and availability problems.
Figure 2 General Network Diagram to Deploy Load Balance
End-user requests are sent to a load-balancing device that determines which server is most capable of processing the request. It then forwards the request to that server. Server load balancing can also distribute workloads to firewalls and redirect requests to proxy servers and caching servers.
Load balancing is the process of distributing service requests across a cluster of servers. There are many benefits to this process, these include:
A key feature of server load balancing is its ability to intelligently direct service requests to the most appropriate server. Extreme Networks switches offer the following integrated server load-balancing algorithms to successfully accomplish this.
Additionally, some load balancers incorporate failure detection. The load balancer keeps track of the server or the application running on the server and stops sending requests to a server after a failure.
The Cisco ACE Application Control Engine Module for Cisco Catalyst 6500 Series Switches and Cisco 7600 Series Routers is a next-generation load-balancing and application-delivery solution.
It achieves these goals through intelligent load-balancing and content-switching technologies integrated with acceleration and security capabilities. A virtualized architecture and role-based administration helps to provision and deliver multiple applications from a single module to increase data centre scalability
Figure 3 Network Diagram to Deploy Cisco Ace
The F5 BIG-IP load balancer is an application delivery networking system that provides the most intelligent and adaptable solution to secure, optimize, and deliver applications, enabling organizations to effectively and competitively run their business. F5 BIG-IP load balancer is the only system that features a set of unified application infrastructure services that deliver total control, vision, and flexibility into application security, performance, and delivery. The result? Greater business agility and successful outcomes for the lifeblood of today's organization -- the application itself.
The Alteon WSM is designed to enable a highly available data centre with no single point of failure. The Alteon WSM can operate in active/active, active/standby, and hot standby modes to ensure non-stop operations while providing parallel processing of Web traffic.
Figure 4 Network Diagram to Deploy Alteon
The Cisco Ace and F5 both are great load balancer in their work and features but still companies prefer to switch to the F5 this is because they have the flexibility to monitor the servers in the datacentres.
The real things that need to look at are Cisco has cli skills, the F5 has a simple web front end and the Cisco GUI just can't compare.
Alteon is also a competitor of Ace and F5 but in performance it is not that much good and considered as compared to Ace and F5.
Server load balancing is a powerful technique for improving application availability and performance in service provider, web content provider and enterprise networks, but piecemeal implementation can also increase network cost and complexity. Server load balancing devices that don’t operate at wire speed can also create their own performance bottlenecks. Extreme Networks provides the key benefits of server load balancing while eliminating the potential cost, complexity, and performance issues.
Distributed server load balancing products can also provide disaster recovery services by redirecting service requests to a backup location when a catastrophic failure disables the primary site.