Foundry Networks' 16 or 24-port ServerIron(tm) Server Load Balancing switch will provide Acme WebSystems with a high density, high performance Layer 4 device that will improve the performance of the existing web servers and ensure application availability. If Acme so desires, the ServerIron could also be used to increase network reliability and redundancy. Unlike other vendors' solutions that depend upon specialized, vendor dependant server software, ServerIron is a protocol-based switch. This ensures compatibility with the currently installed server vendors and operating systems. No special server agent software is required and ServerIron can be used in all of Acme WebSystems' server farm environments used to support the corporate web, FTP, and E-commerce applications.
Acme WebSystems will benefit greatly by adding the ServerIron Layer 4 switch. Specifically, we recommend that you:
- Introduce the ServerIron Layer 4 switch and migrate the eight web servers off of the existing Layer 2 switch and on to the ServerIron.
- Eliminate your existing router round-robin algorithm and use the features now available from the ServerIron:
- Extensive health checking to avoid 'dead servers'
- Graceful shutdown or the ability to instruct ServerIron to stop accepting new connections but allow existing connections to complete their transactions when you need to service a 'live' web server
- Support a new classification of prioritized traffic flows based on a combination of source and destination port numbers for 'critical' (high-priority or essential) web transactions
- Classify, balance, and distribute your web traffic load according to traffic type:
- HTTP
- FTP
- SSL for E-commerce
- URL - content based redirection
- Implement one (or more) of these Load Balancing Algorithms for your selected traffic type classifications:
- Maximum connections
- Least connections
- Round robin
- Weighted percentage
People surfing and interacting with the Acme WebSystems' website will notice a marked performance difference. The corporate users looking for product information and FTP services will receive faster responses and more reliable downloads. The E-commerce customers will experience a more complete and better performing purchasing transaction.
Finally, when Acme WebSystems deploys the ServerIron Layer 4 switches, you'll be able to take advantage of additional benefits offered only by Foundry Networks. Your MIS personnel will be able to spend less time troubleshooting web related problems and have more time for web service planning and execution.
By deploying a second ServerIron in your network configuration, Acme WebSystems will be able offer 'session-level' failover for FTP transactions. In this redundant ServerIron configuration, should the primary ServerIron (which is initially supporting the client's activity) fail for any reason during an FTP download, the backup ServerIron picks up the FTP transaction where the failed device left off. By maintaining 'state-table' information between the two ServerIrons, the backup comes on-line within one second. This occurs transparently to the user, who never experiences any detrimental affects normally associated with a failed device. The download continues without disruption.
Aside from the 'active/standby' configuration, multiple ServerIrons can be deployed in an 'active/active' arrangement. Symmetric load balancing allows you to deploy simultaneously operating devices that also act as mutual backups for each other. As a result, you get the fault protection of a hot standby configuration while doubling connection capacity.
Direct Server Return, another ServerIron feature, instructs the real servers to send client responses directly to the clients instead of sending the responses back through the ServerIron. As a result, the clients receive faster response times and the ServerIron is free to support even more sessions to serve more clients.
Finally, by deploying ServerIron, Acme WebSystems has a platform on which to introduce Network Address Translation (NAT) - to ease the administrative burden of web addressing, and Transparent caches - used to locally store commonly accessed information thereby reducing overall loads on the WAN links.
Acme WebSystems would require a 16-port 10/100Base-TX ServerIron (at a minimum) to support eight multiprocessor web servers. If desired, multiple network interface cards could be installed in the servers, which could provide more connectivity, failover features, and throughput to the server farm. If the number of connections exceeds 16, Acme WebSystems might consider a 24-port ServerIron. Pricing for the 16-port ServerIron starts at $9,995, with service/support contracts, as well as Gigabit Ethernet uplinks also available.
RELATED LINKS
Back to the RFP and other responses
Load balancing forum
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Review: load balancers
All nine products we tested improved Web server performance significantly, making it tough to select a single winner. But in the end, the fastest product under the greatest load, Resonate's Central Dispatch, won our Blue Ribbon Award. Network World, 6/14/99.
Interactive buyer's guide
Find a product that best matches your criteria, compare two or more load balancers in several categories or download a spreadsheet with all the product data.
User study: Dense traffic drives Web-server load balancing
With nearly 60 Web servers, the West Group needed load balancing quickly. See what they decided on and why. Network World Fusion, 6/14/99.
