Predictable Application Response at Any Network Distance with TotalTransport™ Technical White Paper Predicable Application Response At Any Network Distance with TotalTransportTM Page 2 Executive Summary With application workflows traveling over standard IP networks across states and continents, remote workers need fast, predictable response times. That’s what TotalTransport1 technology delivers. With an Internap® Flow Control Xcelerator solution placed at each end of a network circuit, workers get LAN-like throughput and reliability across the wide-area circuit. That kind of performance is now a necessity for collaborating beyond the office LAN. Fast throughput is required for manufacturers doing collaborative design and engineering, media-related companies exchanging digital media assets, and every company that transfers large files over long distances as part of a collaborative workflow. TotalTransport is application-and protocol-independent: it works for any application running over an IP network that utilizes standard TCP-based flow control. TotalTransport works for all business application traffic, all the time. A key benefit of the technology is that it will safely and effectively fill the pipe provisioned between any set of offices. TotalTransport is needed because of a phenomenon associated with traditional TCP/IP-based networks: as distance and bandwidth increase, the effective throughput of the network decreases. This throughput degradation, which seems counter-intuitive, is an unintended consequence of the simple, but elegant algorithms that govern IP networks and have enabled the Internet’s extraordinary growth. TotalTransport provides a standards-based improvement to the original IP design, enabling business application traffic to fully utilize the network resources at their disposal. TotalTransport fills the pipe for all IP traffic all the time. 1 TotalTransport Technology is a patent-pending technology developed by Orbital Data. Predicable Application Response At Any Network Distance with TotalTransportTM Page 3 Understanding Network Application Furthermore, using conventional TCP, only the state of the Response Time individual connection between the sender and receiver is factored into the calibration of the data flow between them. The endpoints are not aware of the other conditions around IP networks, including the Internet, use the TCP protocol for them, or within the network, until something “breaks” (such as most application communication. TCP is short for packet loss or round trip timeouts). To someone gauging Transmission Control Protocol. The IP protocol specifies how network performance from the outside, this usually is seen as packets are routed, while TCP handles flow control, a fairly gradual increase in latency and diminution in response congestion control, retransmissions, and in-order delivery of time. data. As seen in Figure 1 as the distance between any two The IP protocol actually is shorthand for a whole family of endpoints (Client A and Server A) is increased the round trip protocols, usually referred to as the IP protocol stack. The IP response time of any packet is increased thereby reducing stack consists of layers. Each layer corresponds to a different the sensitivity of the system. Furthermore if the problem or aspect of communication. The point of designing IP this way is congestion in the network is actually being caused by Client B that it is flexible and protocols built on top of it do not have to and Server B then the Client A and Server A endpoints are be monolithic. For example, the FTP protocol running on unaware and will be adversely affected. TCP/IP is only concerned with the transmission of files and does not need a full network protocol implementation. Conventional IP networks can be too slow for today’s business-critical collaborative workflows that occur across The IP networking protocol was developed in the early 1970s remote offices over public or private IP networks. by pioneering engineers Bob Kahn and Vinton Cerf. By 1983, ARPAnet, the forerunner of today’s Internet, adopted TCP/IP These problems with conventional TCP/IP and legacy flow since experts realized that the adoption of a single networking control become apparent when data flowing over a WAN protocol would be an important step toward maintaining order encounters bandwidth and latency transitions, for example, within the growing community that was to become the Internet. when bridging to a LAN (Local Area Network). Congestion TCP/IP provided a technological bridge for small networks to occurs, resulting in packet discards that cause throughput and connect to the Internet much more easily than before. transaction times to vary unpredictably. Moreover, latency between the endpoints and the congestion points becomes a TCP is brilliant engineering, but it must be viewed in the problem. Latency makes a control loop particularly hard to context in which it was conceived. The Internet was originally manage, because response data is not real-time. A good way designed to facilitate relatively low-bandwidth communication to think of this is to picture adjusting the hot and cold water in and asynchronous data sharing between government and your shower. Because of the delay in the pipe’s reaction to education facilities. When TCP was first tested and your adjustments, the temperature must be adjusted very implemented, the dominant application was email with its very slowly to avoid getting too hot or too cold. The endpoint-only small payloads, and WAN circuits were measured in the transport implementation of TCP causes the same sluggish hundreds of kilobits. response. With TCP as it was conceived, and as it is implemented today, Clearly, endpoint-only control is not good enough to speed flow control is confined to the endpoints of a network. But it’s flow control. What’s required is adaptive behavior at the point in the interior of the network where most of the problems occur of congestion, enabling networks to establish a feedback loop that induce latency, packet loss, and unpredictability. With without undue delay due to latency. Network technologies, conventional TCP, only the endpoints communicate to each such as SNA (Systems Network Architecture) and Fibre other. As the distance between the endpoints increases, so Channel, solve this problem, generally by putting transport does the amount of time it takes for the network to respond to control at every hop in the network. But these solutions are problems occurring anywhere between. problematic because it results in networks that may not be Predicable Application Response At Any Network Distance with TotalTransportTM Page 4 Figure 1: The legacy flow control provided by a conventional IP network causes slow and unpredictable application response time. TCP/IP compliant and are difficult and expensive to deploy WAN optimization techniques evolved: most notably, caching and maintain. and compression. These techniques attempted to address bandwidth limitations by either not re-transmitting payloads Collaborative Workflows on the Internet (caching) or compressing them so that they require less resources. Caching and compression are very effective tools Business application use of WANs has evolved over time, as for solving some problems associated with bandwidth has network bandwidth (see Figure 2). It surely comes as no limitations for asynchronous communications and transactional surprise to note that as time goes by businesses are making applications. But they are not suitable for all network traffic, and more use of WANs, and network bandwidth is increasing. they do not work all the time. The original use of wide-area networks was for email and While it’s obvious that business usage of WANS, and network asynchronous communications. Over the succeeding years, bandwidth is increasing, what is less obvious is that today’s more complex applications evolved, such as Customer collaborative workflow process has enormous consequences, Relationship Management (CRM) applications and interactive often involving the transport of large digital payloads over Web applications. Many of these applications involve multi-megabit circuits. Examples include: transferring larger files. • Collaborative engineering with Product Lifecycle Management (PLM) products These applications required far better throughput to perform well than earlier “svelte” applications, and in response, several Predicable Application Response At Any Network Distance with TotalTransportTM Page 5 Figure 2: Increasing network bandwidth over time. • Digital media workflows involving Digital Asset These applications are increasingly in need of a delivery Management (DAM) products infrastructure that will enable them to fully utilize the available • Remote visualization of three-dimensional data in bandwidth between offices. medical workflows and geo-physical analysis. With the emergence of metro-area Ethernets and Multi- Protocol Label Switching (MPLS), wide area IP networking is In each of these kinds of applications (and many others that now evolving into “transparent LAN bridging.” Here, the goal is may or may not involve transmitting large-sized files) neither to merge LANs and WANs into one very high bandwidth caching nor compression may be an option, and bandwidth network “cloud,” where all applications behave as if they were limitations are often not the underlying cause of slow, on a LAN and distance is not a factor. One application that unpredictable throughput often – but certainly not always – stands to benefit from this trend is IP storage, where the wide- when large-sized files are involved. The real culprit is the area distributed file-systems behave as if they were LANs ineffective use of the bandwidth at a distance. In other words, interconnected over IP. the pipes may be there, but they are not being utilized. There is a great need to effectively and safely utilize the bandwidth Tomorrow’s transparent LAN-bridging world requires that is already in the pipe. underlying IP networks that operate at gigabit speeds and beyond. These networks cannot afford degradation of response time. Predicable Application Response At Any Network Distance with TotalTransportTM Page 6 The Problem Refined The idea is to enhance standard IP networks with an updated, highly sophisticated implementation of flow control. With traditional endpoint-controlled TCP networks, as distance TotalTransport, the technology within the FCX units, is a and bandwidth increase, the effective throughput of the TCP/IP Layer 4 implementation that can accelerate all IP- network decreases. This throughput degradation, which may based traffic, including traffic using FTP, HTTP, SMTP, and seem counter-intuitive, is an unintended consequence of the NFS/CIFS, and other protocols. simple, but elegant algorithms that govern TCP operations. In part, these algorithms have enabled the Internet’s The TotalTransport implementation consists of highly extraordinary growth. sophisticated transport control algorithms that accelerate all the traffic all the time in a way not possible with caching and To send a transmission over TCP, an endpoint controller compression. doesn’t have to know anything about the internals of a network or the nature of the transmission recipient. Absent relatively Rather than just putting the transport intelligence only at the gross error conditions such as packet loss or roundtrip edges of the network, the flow control supported by Total- timeouts, the endpoint controller just keeps on transmitting Transport places it at the network transition points where with no knowledge of throughput degradation on the network. congestion most often occurs. Examples of these critical congestion points include: This absence of knowledge of network internals, and lack of quality of transmission communication with message • Bandwidth transitions, such as a megabit pipe to a recipients, is probably a necessary requirement for a flexible, remote office coming off a gigabit LAN, or at the public IP network. After all, you don’t want to have to know connection from a WAN to a LAN about the equipment your public Internet transmission will be • Latency transitions at the end of a long link, for traversing, or the hardware or software at the other end. But example when public TCP/IP is being used to this very flexibility of architecture leads to bandwidth transmit digital assets to a remote site thousands of degradation as transmissions hit internal bottlenecks without miles away adequate feedback. • Data links subject to media losses, such as at a wireless network hub because wireless To drill down on this point a bit further, in a conventional IP transmissions are subject to greater packet loss network, an interior node handles a bottleneck by dropping packets. The network then relies on the end-points to detect TotalTransport divides the end-to-end control loop into the loss, recover from it, and adapt network conditions to sections that are managed independently. WAN flow control prevent further loss. The scheme works fine within the is optimized for long-distance transport using powerful confines of a LAN. But over the longer reaches of a WAN, algorithms developed following an extensive research and edge intelligence is not enough – in part because it takes so development effort. long for the edge nodes to become “aware” that a problem has occurred deep inside the network. The algorithms employed by TotalTransport to enhance flow control are an extension to the classic TCP/IP model. So the The TotalTransport Solution good news is that TotalTransport, unlike other performance enhancements, is fully TCP/IP compatible. This means that TotalTransport is implemented within two or more FCX units TotalTransport solves one of the biggest problems with other and uses advanced flow control, retransmission, and performance-enhancing approaches: network incompatibility. congestion control algorithms in a point-to-point or many-to- Other approaches convert TCP/IP packets into proprietary many mesh as shown in Figure 3. formats. Doing so may enhance flow control performance, but it does so at the cost of making the packets unintelligible to firewalls, intrusion detection systems, load balancers, network monitors, and other network equipment. Predicable Application Response At Any Network Distance with TotalTransportTM Page 7 Figure 3: Placing FCX units at strategic network locations results in highly responsive and adaptive flow control mesh. Since TotalTransport is a Layer 4 TCP/IP implementation, standard TCP-based applications don’t “step” on voice and packets are fully TCP/IP compatible from end to end, video streams, thereby causing the annoying stutter so often preserving your investment in equipment and operations, and experienced today. making it easier and less expensive to maintain your network – now, and in the future. Inside TotalTransport TotalTransport addresses the need to deliver fast, predictable As noted earlier in this White Paper, a deployment of the response time as part of a collaborative workflow process, TotalTransport technology requires the use of at least two often involving the transport of large digital payloads over FCX units. The units should be installed at potential multi-megabit circuits. As discussed earlier in this White bottlenecks, for example LAN/WAN connections. It’s a great Paper, these large digital file transfers are becoming an benefit that the TotalTransport technology can be deployed increasingly significant part or modern collaborative business incrementally. You can start with two units at the most critical practice. TotalTransport enables these collaborative business transition points, then add additional units later on as the workflow applications to more effectively use the available benefits of TotalTransport become apparent, and as your bandwidth and provide reliable, fast response times at each network traffic increases as seen in Figure 4. step of the workflow process. With TotalTransport, IP packets pass through an FCX unit. Today and tomorrow’s real-time multimedia applications will Each FCX unit has three functional components: increasingly consume available bandwidth. TotalTransport can help you provision your bandwidth to insure that Predicable Application Response At Any Network Distance with TotalTransportTM Page 8 • A receiver, which accepts the packets passed to it on the Figure 4: TotalTransport can be used in a point-to-point or LAN or WAN many-to-many mesh depending on the deployment. • A sender, which sends packets on through the network to another FCX unit on the WAN or to a LAN destination • The deep-packet inspection and policy engine The deep-packet inspection and policy engine is the heart of the FCX TotalTransport unit. Packets received by the FCX unit receiver are passed through the application-aware deep-packet inspection engine to the sender, where they are sent on. The deep-packet engine provides the intelligence needed to decide which packets get sent, and when. The algorithms make a policy decision about which packets get sent first. This policy is derived from two factors: • Management policy, driven by the deep-packet inspection conducted by each FCX unit individually. • The state of the entire network, based on information collected by all FCX units on the network. This breadth of information is what makes TotalTransport so effective at the important task of allocating network bandwidth carefully. When the packets arrive, the engine not only derives substantial information about the specific connection that the packet traversed, but also has available the broader view of network connections, as gathered by other FCX units. Thus, the information exchanged between FCX units is much richer than what is utilized at the edges of a conventional IP network. An active feedback mechanism, combined with informed management decisions about which packets are sent first, result in greatly improved network performance (your WAN will feel like a LAN!). TotalTransport provides a rich communications link between FCX units, which are best deployed strategically at network transition points. As a Layer 4 TCP/IP implementation, TotalTransport provides the required services in a way that is fully and completed TCP/IP standards compliant. The FCX units make intelligent, WAN-optimized transport decisions, resulting in more efficient allocation and full utilization of bandwidth. When that happens, throughput approaches Predicable Application Response At Any Network Distance with TotalTransportTM Page 9 the limit of the bandwidth available in the pipe without the application protocol acceleration handle only some of the corresponding degradation in response-time predictability network traffic some of the time and/or create IP network that occurs with standard IP networking. This results in the compatibility issues. best possible network performance and application response time. Network utilization rates go up, and the pipes The TotalTransport technology implemented in FCX units is fully are safely and effectively filled. TCP/IP compatible. TotalTransport provides intelligence about bottlenecks deep in the heart of the IP network, and helps TotalTransport is application and protocol independent. It speed all the traffic, all the time. works for any application running over an IP network that utilizes standard TCP-based flow control. TotalTransport Organizations that make effective use of TotalTransport FCX works for all business application traffic, all the time. It is can units can increase the efficiency of their networks with relatively be used in concert with or instead of other optimization little effort, and help fill their pipes to capacity safely and strategies, such as caching and compression. effectively. TotalTransport provides predictable and fast application response time. TotalTransport technology will safely and effectively fill the pipe provisioned between any set of offices, no matter whether the public Internet is used or whether a private TCP/IP infrastructure is deployed at one or both ends. Conclusion IP networks provide inadequate intelligence about internal bottlenecks, making it hard to effectively utilize available bandwidth resulting in slow application response time. Optimization techniques such as caching, compression, and For more information contact: Internap Network Services 250 Williams Street Atlanta, GA 30303 Tel: 404.302.9700 or 877.THE.PNAP Fax: 404.475.0520 © 2004 Internap Network Services Corporation with permission from Orbital Data Corporation. All rights reserved. Internap is a registered trademark of Internap. Total Transport is a trademark of Orbital Data. All other trademarks and brands are the property of their respective owners.
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