Technology Primer: Inside the Blue Coat CacheFlow Appliance
Inside the Blue Coat CacheFlow Appliance
Blue Coat has been a leader in web caching since the company was founded in 1996. The new Blue Coat
CacheFlow™ appliance builds on a rich legacy of customer-proven technologies for web caching – including
roughly 20 patents – to help carriers significantly save on bandwidth while providing an enhanced user
experience. The new appliance is designed for the growth in traffic that carriers are experience today with more
users, connecting from more devices, and for longer periods of time.
The caching technology built into the
CacheFlow appliance has been evolved to
address the ever changing nature of the
Internet. This includes new technology
tailored to effectively cache rich media
content like video, file download sites, and
dynamic Web 2.0 content. With the new
CacheFlow solution, carriers can save
40-50% on bandwidth, while boosting the
user experience and putting in place a
platform for future, revenue-generating and
differentiated services.
40-50% bandwidth savings; general web traffic
It’s important when evaluating the
CacheFlow appliance to first explore the
advantages inherent to the highly optimized and integrated design of the solution. For example, the CacheFlow
appliance leverages a custom, real-time operating system (OS) specifically designed for performance. This
allows the solution to perform much better and at higher throughput levels than similar solutions, including
appliances, running on a general-purpose OS, such as Linux.
Also for performance, the CacheFlow appliance employs an object store specifically optimized for caching web
objects, including special tuning for web access patterns, eviction algorithms for object handling designed
to maximize bandwidth savings, in-memory caching for frequently accessed objects and automatic space
management for best disk utilization. The closed and highly optimized design of the CacheFlow appliance
and the web caching object store also lends itself to greater security and data privacy than general-purpose
approaches. The CacheFlow appliance also has a rich, policy architecture with flexible checkpoint mechanisms
for handling traffic in unique ways, whether related to filtering or custom rules for caching certain types of
content.
One of the big advancements of the CacheFlow appliance has been a focus on the carrier market and in
particular the operational fit of the solution into carrier environments, both in terms of how the product scales
and is highly available, but also in terms of how management, monitoring and reporting is done. In particular in
the reporting area, CacheFlow has very rich access logs which provide a great deal of customizability in terms
of the reports that can be generated.
Since Blue Coat has been in the business of web caching for nearly 15 years, there is robust experience specific
to the Hypertext Transfer Protocol (HTTP) and handling protocol exceptions that are very common in the wilds of
the global Internet. As web content increasingly gets more rich and interactive, especially with video, Blue Coat
also has broad licensing agreements and protocol experience – for example with Real-Time Streaming Protocol
(RTSP), Real-Time Transport Protocol (RTP), Real Data Transport (RDT), Multimedia Messaging Service (MMS)
and Real-Time Messaging Protocol (RTMP) – that complements that CacheFlow product strategy.
Technology Primer: Inside the Blue Coat CacheFlow Appliance
In terms of advancements of the caching technology available only in the new CacheFlow appliance, there are a
number of areas where the caching techniques are quite different than the legacy Blue Coat ProxySG appliance
and competitive offerings. One area of advancement has been to enhance the object store to optimize for and
better address large objects in the store and on individual disks within the CacheFlow appliance. This aligns
with the general shift with Web 2.0 (and beyond) toward large file downloads and rich media content, like video.
CacheFlow also uses greater intelligence in terms of the decisions made about what content to cache or
evict from the cache. For example, this caching intelligence takes into account the size of the object under
consideration both in terms of its potential bandwidth savings, as well as things such as popularity. To
maximize bandwidth savings, partial object caching is supported such that a user downloading a large video
and only watching part of it will still propagate the cache with this partial video object, such that the next user
requesting the content will save that bandwidth plus benefit from the boosted user experience of being able to
access the content locally from the cache.
With Web 2.0 other changes in caching
are necessary, for example in using
information other than the Uniform
Resource Locator (URL) as the unique
identifier of a cached object. CacheFlow
uses metadata about the content itself
to uniquely find an object in the cache,
which helps ensure smart caching and
serving of content even if delivered from
a dynamic URL or the same content
available on different web links or with
different file names.
Other tuning specific to Web 2.0 sites
available with CacheFlow include
features like caching response data on
HTTP POST requests which is required
for example to effectively cache content served from many file sharing sites, which are increasingly becoming
popular alternative to peer-to-peer (P2P). To further drive the greatest bandwidth savings, CacheFlow also
employs server pacing techniques to synchronize the download speed between the server and client. This helps
ensure that bandwidth is not unnecessarily burned ahead of the user or in the case where the user abandons
the web request.
Beyond the tuned nature of the appliance solution and its baseline bandwidth-saving techniques for caching,
CachePulse™ is one of the most significant technical advancements in the CacheFlow appliance. Where in the
past customers would need to custom tune policies over time to boost caching effectiveness and ultimately
bandwidth savings, CachePulse provides a cloud-based approach for rapidly updating the caching rules and
instructions over time as the web changes.
Especially with advancements seen in web content and the overall traffic mix moving from Web 1.0 to Web 2.0,
this ability of a caching solution to evolve over time is critical. Most competitive products either require tuning
or in the worst case an entire software or solution upgrade to take advantage of new caching techniques. In
comparison, CachePulse can quickly – on as little as 20-minute increments – download and take advantage of
new caching techniques.
Technology Primer: Inside the Blue Coat CacheFlow Appliance
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Network
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PB
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L4
Switch
PB
CachePulse™
Database Updates
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Backbone/IP Transit
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L2
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Subscriber
Requests
WebPulse™
Dynamic URL Ratings
CachePulse operates as a global cloud infrastructure, leveraging the redundant data centers used today for
the Blue Coat WebPulse™ cloud for security – which services tens of millions of users and billions of requests
per day – to deliver specific instructions to deployed CacheFlow appliances. Engineers from Blue Coat use
CachePulse to target the right caching techniques for consistent, effective caching for a specific website or
domain. Leveraging a ‘crowdsourcing’ approach, customers participate in the CachePulse service by providing
active feedback on new and emerging sites that need to be cached, which allows the CachePulse cloud and
service to evolve over time for global coverage and maximum, sustained bandwidth savings for all customers.
Whether a global tier-one carrier or a regional access provider or mobile operator, CacheFlow provides a
compelling solution to help address the strong demand for rich web content and applications both in terms
of managing costs, providing key infrastructure for scaling and ensuring a quality user experience, as well as
monetizing traffic and delivering new services.
To learn more about the CacheFlow appliance, visit http://www.bluecoat.com/cacheflow.
Blue Coat Systems, Inc.
www.bluecoat.com
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Sunnyvale, CA USA // +1.408.220.2200
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Copyright © 2010 Blue Coat Systems, Inc. All rights reserved worldwide. No part of this document may be reproduced by any means nor translated to any electronic medium without the written consent of Blue Coat Systems, Inc. Specifications
are subject to change without notice. Information contained in this document is believed to be accurate and reliable, however, Blue Coat Systems, Inc. assumes no responsibility for its use. Blue Coat, ProxySG, PacketShaper, CacheFlow,
IntelligenceCenter and BlueTouch are registered trademarks of Blue Coat Systems, Inc. in the U.S. and worldwide. All other trademarks mentioned in this document are the property of their respective owners. v.TP-INSIDE-CFLO-APP-v1-0810