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Date: 16-09-14

WAN accelerator technology from Fujitsu double n/w speed

WAN accelerator technology developed by Fujitsu Laboratories can double the transmission speeds on WAN n/ws. Fujitsu has developed new acceleration technology on software and tests were conducted with the National Institute of Informatics, which have conformed doubling of the transmission speeds of previous WAN acceleration technology when using mobile devices in Japan to access cloud services abroad.

The previous technology uses identical accelerator hardware at both endpoints of the WAN without having the capability to accommodate for the differing characteristics of the network. Whereas the technology from Fujitsu features accelerator is distributed throughout WAN to automatically select the communication protocols best suited to the network characteristics between accelerators.

Along with addressing the increasing demand for network bandwidth, new technology from Fujitsu when applied to network functions virtualization (NFV) enables the provision of fine-grained network services that are coordinated with a variety of network functions, such as firewalls and load balancers, says Fujitsu.

Below is the background this technology presented by Fujitsu in its release:

Many communications applications today have standardized on TCP, the Transport Control Protocol. But TCP communications over some wide-area networks, such as international networks, may encounter barriers to performance caused by such factors as high packet losses or long round-trip times. One method used to remedy this decline in performance is to install specialized equipment called WAN accelerators at both ends of a WAN, replacing the TCP protocol with acceleration protocols.

Existing accelerators use a long-distance acceleration protocol, packet-loss acceleration protocol, and short-distance acceleration protocol , and will automatically pick the one that yields the best performance for the network and application characteristics (Figure 1).


Figure 1: Conventional WAN accelerator technology

With the spread of cloud services and high-speed wireless communications such as LTE, there is an increasing volume of traffic from mobile devices, which, from numerous locations, are used to access cloud services. Increasingly, therefore, WAN accelerators are being used in WANs that comprise different kinds of networks, including intra-city, inter-city, and international, each with their own different characteristics (Figure 2).


Figure 2: Configuration of conventional technology

In simple terms, picturing conventional WAN accelerators as located at the borders between networks and selecting acceleration protocols suited to the network characteristics between each pair of accelerators, there will be situations in which throughput improves for large-scale file transfer applications. By contrast, with "chatty" applications, however, such as virtual desktop applications, in which relatively small bits of data travel back and forth, because the transmission time for each bit of data traveling back and forth is extremely short, overall data transmission times are, conversely lengthened because of relay delays at each accelerator.
About the Technology

What Fujitsu Laboratories has developed is a technology whereby multiple accelerators are distributed throughout a WAN, and, in accordance with the characteristics of the communication applications and the network characteristics between the accelerators, and they automatically select the most suitable communications protocols, as well as the corresponding sections of the network to which they apply.

The distributed WAN accelerators are controlled in the following sequence (Figure 3).
WAN accelerators are placed at the borders of networks so that acceleration protocols can be chosen in response to the different characteristics of each network.
Each WAN accelerator sends to a controller the relay delay time needed for protocol conversion, the network characteristics between each accelerator, and, as estimated by monitoring the target application's port number and the data being relayed, the size of the data that the communications application is transferring.
The controller calculates the communications performance of each acceleration protocol as estimated based on the characteristics of the network between accelerators. Based on the relay delay time and calculated communications performance, it determines the most appropriate logical section and the accelerated protocol to use over that section that will minimize the time needed to transfer the estimated data size.

As a result, as shown in Figure 3A, when transferring a large file, in comparison with the file transmission time, the relay delays at each accelerator are insignificant enough to be largely disregarded, so the number of sections is increased to improve throughput. By contrast, with interactive communications, as shown in Figure 3B, to minimize accelerator relay delays, some of the accelerators are disabled to reduce the number of sections.

Figure 3: Distributed WAN acceleration technology
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We developed the technology on software and evaluated it cooperating with NII using SINET and wireless LAN service eduroam (Figure 4). It was confirmed that in communications on the Japan-North America leg, the acceleration protocol and the section for it were dynamically determined in response to the communications application and the quality of the communications environment between accelerators. For file transfers, the selection chosen was to divide over multiple sections, resulting in transmission speeds roughly doubling. For interactive communications, for cases in which there was no packet loss, the selection chosen was to divide using the same sections used with conventional technology, and there was no performance degradation in the data transmissions. When there was packet loss in interactive communications, the system opted for multiple sections and to allow resends from the WAN accelerator nearest to the client device, which resulted in data transfers in less time than with conventional technology (Figure 5).

The use of this technology could make it more efficient for people on two different continents to collaborate on the same 3D CAD drawing.


Figure 4: Evaluation testing on SINET4

Figure 5: Acceleration results

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