TotalTransport Technical White Paper by tlindeman


									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.

         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.
                                                                                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.


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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