1. SERVER LOAD BALANCING Presented By : Priya Palanivelu

2. Server Load Balancing Server Load Balancing ?? Distributing service requests across group of servers End-User requests sent to load balancing device that determines which server is the most capable of processing the request. It then forwards the request to the server

3. CLIENT SERVER FARM GATEWAY SERVER FARM GATEWAY ROUTER LOADBALANCRLOADBALANCR SW SERVER SERVER LOAD BALANCING

4. Server Load Balancing SLB Working ?? Server Load Balancing makes multiple servers in the server farm appear as a single server A single virtual service by transparently distributing user requests among servers Made possible by Virtual IP-Address

5. Server Load Balancing Benefits Increased Scalability Flexibility to deploy additional servers quickly and transparently to end users High Performance Directing end-user service requests to servers that are least busy thereby achieving fastest response time High availability & Disaster Recovery During server failures, load balancers can automatically redistribute end-user service requests to other servers with in server farm or to servers in another location

6. INTERNET ROUTERS LAYER 2 SWITCHES SERVER LOAD BALANCERS LAYER 2 SWITCHES SERVER FARM INTEGRATED SERVER LOAD BALANCING

7. Integrated Server load Balancing Benefits SLB is a overlaid service on existing network infrastructure Integration with routers, switches Capabilities of Policy-Based QoS, access policies & system security Wire speed performance for server load balancing Lower cost

8. SLB-Specialized Environments Specialized Environments?? For applications that require processing- intensive features as URL/Cookie (e.g.) A broken session can result in a shopping cart losing contents on an e-commerce site Redundancy & Layer 3 routing functions possible for virtual services

9. Distributed Load Balancing This gives users access to servers that are geographically distributed across WAN Made possible by 3DNS 3DNS a wide area traffic manager 3 DNS maps domain names to IP address of appropriate server

10. Distributed Load Balancing (Cont..) Advantages DLB creates a single “ Virtual Site Environment” that centralizes the management of geographically distributed Internet sites and data centers, giving end-user a single URL with transparent access to multiple servers in multiple geographic locations

11. Disaster Recovery Mission-critical applications can be replicated at a disaster recovery site If primary site becomes unavailable, the workload is automatically redistributed to backup site