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Figure 1.
Spend More for More Bandwidth
When faced with the need for more network performance, many information technology (IT) managers decide to buy more bandwidth from their incumbent service provider. Increasing the size of the pipe or buying more bandwidth is a good solution to increase the capacity of a network. However, increased capacity does not optimize network performance—rather than improving poor network behavior and efficiencies, these shortcomings are amplified. The behavior that created traffic demand, now reinforced, will quickly increase to take up the capacity of the enlarged pipe through which it is traversing. A solution is needed that optimizes network performance and eliminates repeat or unwanted traffic from the infrastructure.
In a non-optimized network, bandwidth demand is a linear function of the number of users (assuming the same applications are used). More bandwidth does not add increasing value; it just adds more capacity. In contrast, Enterprise Caching adds value to the network. More users employing the same applications generate a greater number of similar traffic patterns. Therefore, each additional user consumes less bandwidth, since more of their content is served from the cache.
In addition, availability and lead times for circuit upgrades vary regionally. Last-mile bandwidth upgrades are unavailable, especially in bandwidth challenged areas—high-density metro areas where demand is exploding, rural areas, and developing countries. It may be months, if not years, until higher-bandwidth circuits become available. A more immediate solution is needed.
More bandwidth also has significant cost drawbacks in terms of addressing network performance:
- It adds to the recurring cost of bandwidth—an annuity to be paid out to the service provider.
- Upgrading single circuit to fractional T1/E1 or adding additional lines adds equipment expense in terms of routers, channel service units (CSU)/data service units (DSU) or network termination units (NTU), etc.
- Upgrading infrastructure has a significant operational cost in terms of support, maintenance, and training.
Alternatively, Enterprise Caching helps to manage network growth by providing optimal return on network infrastructure. Enterprise Caching optimizes the utilization of any pipe—existing or new. Network growth can then be driven by new traffic demand, which is driven by new data, not from increased usage of repeat data.
Spend Less, Do More
Apart from increased network capacity, four technologies have emerged that enable enterprises to optimize the throughput of their corporate networks. Each of the following solutions addresses a different performance issue, and all four technologies are complementary.
Bandwidth Management
Bandwidth management helps enterprises to better use existing network capacity by aligning the network with business priorities. Typically, this represents prioritizing mission-critical or delay-sensitive traffic over non-critical traffic. From the perspective of total throughput, it is a zero sum gain.
The available bandwidth is divided among the users and applications. Each network circuit is analyzed to identify the users and applications using the link, and priority rules are established to prioritize users and/or applications. This process must be repeated every time new business priorities related to new users and applications are added to the network.
Enterprise Caching is fully compatible with bandwidth management. While Enterprise Caching increases the overall capacity of the network, bandwidth management prioritizes the available capacity according to business rules.
Web Caching
Web caching helps to reduce response time for access to Web content. Web Caching brings static content closer to the end user, therefore delivering better turn-around time for content access and decreased traffic usage. Industry statistics on the performance of Web caching indicate an average throughput increase of approximately 30%. It addresses mostly static and streaming Web content.
Enterprise Caching, while providing a 50–100% increase in throughput for Internet traffic, also provides several hundred percent for other enterprise traffic, including rapidly growing traffic types such as common gateway interface (CGI), active server page (ASP), Java, B2B, and extensible markup language (XML). Enterprise caching also addresses the significant amount of corporate network traffic today (around 75% on average) that is not Web-related, delivering 100–400+% acceleration on those traffic types.
Enterprise Caching and Web caching are not mutually exclusive; they can co-exist to further enhance network performance. How? Enterprise Caching optimizes the traffic of data, which is not served locally.
The Legacy of Data Compression
Data compression was very effective in the past, specifically with certain types of files, (such as text files). However, data compression has lost its value in today's corporate environment, as it is not effective when it comes to "random" data such as the documents used by enterprises today—Microsoft Word files, PowerPoint presentations, Excel spreadsheets, images, Zip files, etc.
When porting data compression to real-life packet-based networks, vendors, as well as users, have found that data compression is less effective. Data compression usually provides less than 5–10% bandwidth improvement when applied to corporate traffic, including intranet traffic using "Web" technologies. The reason behind this is that corporate networks and Internet technologies usually carry precompressed material, and packets usually carry very little resemblance to prior packets.
