December 27, 2006

Computing appliances — architected for network stream processing

I’ve been researching computing appliances quite a lot recently, including for an upcoming trade press column. As part of the research, I circulated preliminary thoughts and questions to a variety of appliance vendors. One, Barracuda Networks, responded at length via e-mail. Credit goes to Steve Pao, VP of Product Management. I’m posting the interchange below.

Q1. Stream processing is different from conventional business computing. Different hardware architectures are commonly appropriate.

A1. Stream processing is different, particularly for enterprise networks, because data in the stream should not back up during processing to create latency. In traditional business computing, total throughput is measured more often than latency. Minimizing latency requires careful attention to layering processing to handle as much as possible with the least expensive operations first, keeping the footprint as small as possible to minimize any virtual memory swapping, and minimizing I/O. There are some hardware considerations, but this is often over-emphasized. As applications delivered through appliances continue to grow in complexity, software architecture plays an often under-represented role.

Barracuda Networks has designed the architecture of its appliances with these characteristics in mind. For example, the Barracuda Spam Firewall’s architecture leverages 12 defense layers, focusing on those layers that require the least processing upfront. This layered approach minimizes the processing of each spam message, which yields the performance required to process email for tens of thousands of users in a single appliance.

CAM note: This kind of “it’s the software, stupid” response is typical of what I hear from appliance vendors.

Q2. For most kinds of appliances, custom chips are nice-to-have but not must-have. And by the way, if there are “custom” chips, they will usually actually be FPGAs.

A2. Custom chips are useful for very high volume/low cost appliances because they can help reduce cost of goods. That said, for most enterprise-class networking and network security appliances, off-the-shelf chips generally provide the performance and flexibility to deliver performance for today’s networks.

Q2A (followup): Looking into this further, I’m getting the sense that boxes are custom but components are not. That is, appliances with a stream-processing flavor commonly include networking cards that, while standards, aren’t common in general-purpose computers. Encryption also is commonly handled by specialized chips.

A2A. Yes, delivery of appliances often requires use of components that, while standard, are not typically used in general purpose computers. Even beyond hardware that vendors may use to enhance system performance, there are also hardware components that are included for the reliability requirements of networking appliances.

For example, the Barracuda Web Filter and Barracuda IM Firewall are network appliances designed to be deployed inline. On the Barracuda Web Filter models 310 and higher and the Barracuda IM Firewall models 320 and higher, the appliances include an Ethernet hard bypass that fails “safe” – allowing traffic to flow through – in the event of system failure.

As another example, the Barracuda Load Balancer is diskless and boots from high capacity flash memory.

Q3. Deliberately limiting the capability of the system makes it harder to hack. But this is important only in security appliances, and I’m not so sure it’s important even for them.

CAM note: The answer below confirms what I said, but with more accurate phrasing.

A3. It is common practice to minimize the number of traditional operating services in order to reduce the potential for vulnerabilities in the system. Every component that is used has the potential to open another vulnerability. That said, today’s applications require a level of sophistication that also requires more underlying services than ever before. As such, the important thing is to have a great internal development process for system design and maintaining a great relationship with the “white hat” security research community. Of course, while larger vendors are larger targets for exploits, they also have the advantage of having the notoriety to attract top security researchers to work with.

Q4. A huge part of appliances’ appeal is ease of deployment and administration. Applications used to arrive bundled with hardware very commonly, especially for smaller buyers (and for them it’s often true even today). Appliances offer the same benefit for system software.

A4. We agree with this assessment. Customers usually can get a Barracuda Networks appliance completely deployed in less time than it takes to load an OS onto a hardware platform – let alone install or configure software applications.

Q5. There’s a lot of grumbling about appliance maintenance costs, as appliance vendors charge percentage-of-purchase-price fees that would be appropriate for packaged software and apply them to the whole bundled hardware/software appliance.

A5. Interestingly, the appliance vendor often has to do more than a traditional software or hardware vendor. There’s a set of support issues that a traditional software vendor can simply sidestep because they don’t support the OS on the hardware. A hardware vendor can generally wash themselves of all issues not related to hardware. What the customer gains from support from a good appliance vendor is a complete solution and no finger pointing. All that said, if the appliance is overpriced, the customer may not get a good value. Customer should always look at the value and absolute dollars as opposed to percentages.

Barracuda Networks does not charge on a per-user basis. Customers pay a one-time fee for the appliance and a recurring yearly fee for Barracuda Energize Updates which include not only basic technical support and firmware updates but also, depending on the product, ongoing virus, spam definition, spyware definition, content filter, IM protocol, and intrusion prevention definitions. For a low annual fee, Barracuda Networks’ customers can deploy secure solutions with virtually no ongoing administration. Energize Update pricing is based on model number and starts at $499 per year.

Optionally, customers can also purchase an Instant Replacement service. In the event of hardware failure, Barracuda Networks products with active Instant Replacement subscriptions can be cross-shipped the next business day to minimize downtime. Instant Replacement pricing is also based on model and starts at $499 per year.

Comments

2 Responses to “Computing appliances — architected for network stream processing”

  1. The Monash Report»Blog Archive » Sendio — no effective response to the niche-forever challenge on January 10th, 2007 12:47 am

    [...] Sendio boasts almost 150 customer enterprises, concentrated in such security-sensitive markets such as financial services, healthcare, and legal services. (One advantage of being security-sensitive may be that your correspondents are open-minded to enduring the challenge/response hassle.) As per a glowing review in Government Computer News – which incidentally takes a swipe at Barracuda – spammers so far do not bother doing anything to defeat the system. [...]

  2. The Monash Report»Blog Archive » Guide to my recent research on computing appliances on January 18th, 2007 5:25 am

    [...] Half or more of the computing appliance vendors I’ve looked into follow very similar hardware strategies: They use mainly standard parts; they include uncommon but off-the-shelf networking (and sometimes encryption) accelerators; and they of course optimize the mix of those parts and general hardware architecture as well. Examples I’ve posted about recently include – and I quote the forthcoming column – “DATallegro and Teradata (data warehousing), Cast Iron Systems (data integration), Barracuda Networks (security/antispam), Blue Coat Systems (networking), and Juniper (security and networking).” [...]

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