SAN MATEO (04/03/2000) - Co-located network infrastructures can get jumbled -- not to mention costly -- when you must have a switch (layer 2), a router (layer 3), and a load-balancing solution (anywhere from layer 4 to layer 7). Having to maintain separate devices allows administrators time to understand them, and almost guarantees no downtime makes everything difficult. Every time a new component is added, life becomes a living hell for those who maintain the systems.
Three devices in one
Alteon WebSystems Inc.'s AceDirector 3 (AD3) and its operating system, Web OS, rolls all of these devices into a single well-designed and powerful solution that also costs much less than the devices cost separately. Although AD3's primary focus is on load balancing Internet services such as HTTP and FTP, its added capabilities make it an ideal device for most co-located businesses.
Typical co-located sites design their network infrastructure in different layers involving different devices.
Because the AD3 can replace most of the infrastructure required in an Internet services load-balancing scenario, it provides businesses with an alternative to the expense of purchasing three different solutions. Not only are hardware costs reduced, but so are administrative costs, because there is only one device to manage, rather than two or three.
I gave the AD3 a score of Very Good for its low-cost, seamless, three-in-one combination, and for providing strong architecture. However, it was bumped down from an Excellent score because of its weaker routing capabilities and lack of support for certain protocols.
Other solutions, such as the Cisco LocalDirector or F5 Networks Big-IP, require the addition of both a router and a switch. Of the competitive products, Foundry Network's ServerIron switches are one of the few competitors with a comparable feature set. The AD3's design sets it apart from the rest because it has two separate processors per port (18 processors total) instead of a single processor at the core, a situation that lets each port function more rapidly than the solutions that require centralized CPU communication.
The primary purpose of the AD3 is to provide load balancing and fault-tolerance across multiple Internet servers. With the current state of technology, solutions to around-the-clock problems usually include redundant machines to solve hardware and software failures. Because this extra hardware is available, it makes sense to distribute traffic across as many devices as possible, while at the same time monitoring these servers. Then, when one goes down, ideally the traffic is dynamically and transparently distributed to the units that are still running.
Alteon has designed the AD3 to provide load balancing across multiple servers for almost all of the standard Internet services including the ever-popular HTTP and FTP, DNS, and SMTP. The product provides these load-balancing services, but it also provides extra features, which make it more robust and feature-rich.
It's a switch!
The AD3 can serve as a layer 2 and layer 3 switch, which can, in some cases, eliminate the need for extra switches or routers. Alteon has allowed each port on the AD3 to function in different modes so that some ports can be layer 3 switches, while others are simply layer 2 switches participating in the same VLAN (virtual LAN). Because of this flexibility, it is possible to reconfigure the AD3 to fit just about any situation.
It's a load-balancing solution!
Load balancing is definitely the AD3's cup of tea. For the past four years, Alteon has been designing and producing powerful switches with load-balancing features, and the AD3 is no exception.
Designed to provide the administrator with options, rather than requirements, for configuration, the AD3 allows load balancing to be configured similarly to the way competitors' devices are configured. In one mode, the AD3 can act like a transparent bridge, much like Cisco's LocalDirector, and in another, it can be configured to act as a routed solution like F5 Network's Big-IP. This allows administrators decide whether or not the layout of their networks will be routed or bridged for load balancing. It also allows for devices behind the AD3 to either be local or remote depending on the desired configuration; this opens many inroads for intelligent network planning that many of the other devices lock you in to because of the way they're designed.
The newest features to be added to the AD3 are the enhancements that Web OS 6.1 adds. The latest revision allows administrators to track cookies and SSL (Secure Sockets Layer) sessions and also to redirect URLs. Using AD3's cookie-tracking feature, I was able to solve a problem that had been plaguing me for a while. I had a business-to-business relationship during which, when a transaction was being processed, the Web users would leave my Web site for a certain amount of time while their transaction was being processed by my business-to-business partner. If they had been on the America Online Web site or another site that uses proxy servers, I couldn't be guaranteed that they would return with the same IP address. Because the AD3 was capable of peeling the cookie out of the session, during testing I was able to make sure that all of the clients returning from the remote business-to-business partner returned to the correct server where their session information was kept. Before this, I had to keep only a single Web server in service while keeping the others online as backups. Now I can distribute the traffic across all of the Web servers and not be concerned that some clients would return to the incorrect server.
The URL redirecting feature provided immediate improvements. Common practice is to maintain separate IP addresses and server names for different functions; for example, an address for an image server (image.infoworldtestcenter.com) would be different from that of a server that contains the dynamic content (www.infoworldtestcenter.com). Using the URL redirection, I was able to make these different addresses transparent to the clients. While testing, I was able to send traffic meant for www.infoworld testcenter.com/images and www .infoworldtestcenter.com to two different servers. This made my client machine load my pages more quickly than it would have if it had to use two different names to download its Web page. It also gave me the advantage of being able to maintain my servers and their functional allocation differently from my Web site design by abstracting the URLs.
It's a router!
Not to be forgotten in the whole picture is both the design of the unit and its extra features. Inside the AD3 are two RISC processors per port. Each port is basically its own computer that only refers back to the management processors and configuration information when needed. This allows each port to process packets independently of each other.
Although this is a tremendous benefit, this is also the area where the switch is lacking the most. In particular, its support of interior and exterior routing protocols is not impressive. Currently it only supports RIP (Routing Information Protocol). However, if you do not need extensive routing, the AD3 is quite capable of providing wire speed layer 3 switching.
Alteon has been working to add new features to the device. Slated for release soon are the global features that will allow the AD3 to balance network traffic between geographically dispersed sites. Also, in the near future, traffic throttling and QoS (quality of service) management features are going to be added to ensure that the most important traffic receives priority. To top it off, Alteon has already realized the deficiencies in their routing support and will soon be adding Open Shortest Path First (OSPF) and a limited stub-oriented implementation of Border Gateway Protocol Version 4 (BGP4).
Of the load-balancing solutions I've come across recently, this was one of the most pleasing units I've worked with. My biggest complaint about the unit is that it teased me by offering so much that I wanted the kitchen sink. But regardless of my pipe dreams about a product that does absolutely everything, the AD3 earned a well-deserved score of Very Good. If you're looking for a load-balancing solution, add Alteon to your list. If you're looking for infrastructure for your co-location setup, put the AD3 on the list as well; its features may surprise you and you most likely will reduce hardware costs and gain capabilities by using one.
Mark Pace (email@example.com) is a free-lance writer who has been working in the computer industry for more than 15 years.
THE BOTTOM LINE: VERY GOOD
AceDirector 3 with Web OS 6.1
Business Case: This integrated solution successfully replaces three different critical pieces of infrastructure hardware, greatly reducing hardware costs.
AceDirector 3 (AD3) is a very good solution for any business that needs load-balanced Internet services. AD3 is very feature-rich, but because of its low cost, businesses should consider it even if they only need a few of its capabilities.
Technology Case: Not only does AD3 offer high-quality load balancing for Web servers, DNS, FTP, and more, but it also performs at wire speeds as a layer 3 switch. Incorporated with the Web OS 6.1 release is the capability for AD3 to read session-oriented content from connections, allowing administrators to redirect connections based on URLs and cookies.
+ Watches cookies to make sure users are returned to the correct server each time they connect+ Redirects traffic to different servers based on URLs+ Provides wire speed layer 3 switching+ Easy to manageCons:
- Currently only supports RIP for internal routing- Lacks support for external routing protocols- No support for multicast routing protocolsCost: $12,995, Web OS 6.1 upgrade is free for AD3 ownersAlteon WebSystems Inc. San Jose, Calif.; (408) 360-5500; www.alteonwebsystems.com.