WELCOME TO SEMINAR
ON SKY X-TECHNOLOGY
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Why sky X- Technology?
Satellites are an attractive option for
carrying Internet and other IP traffic
to many locations across the globe where
terrestrial options are limited .
The Sky X technology replaces TCP over
satellite link with a protocol optimized
for the high loss and bandwidth
conditions of the typical satellite
Adding the Sky X system to a satellite
network allows users to take full
advantage of the available bandwidth
The Sky X technology transparently
enhances the performance of all users on
a satellite network .
The Sky X increases web performance
by 3 times or more and file transfer
speeds by 10 to 100 times.
The Sky X solution is entirely
transparent to end users, works with all
TCP applications and does not require
any modifications to end client and
Why sky X-Technology???
Satellites are ideal for providing
internet and private network access over
long distance and to remote locations.
However the internet protocols are not
optimized for satellite conditions and
consequently the throughput over the
satellite networks is restricted to only
a fraction of available bandwidth.
Thus We need sky x technology to over
come these restrictions and to access
Sky X Technology Overcome TCP
Even though the TCP is very effective in
the local network connected by using
cables or optical fibers by using its
But the satellite conditions adversely
interact with a number of elements of
the TCP architecture, including it s
window sizing, congestion avoidance
algorithms, and data acknowledgment
mechanisms, which contribute to severely
constrict the data throughput that can
be achieved over satellite links.
Thus the advantages achieved by TCP in
LAN's are no longer effective in the
So it is desirable to design a separate
protocol for communication through the
satellite to eliminate the disadvantages
of using TCP over the sat
Sky X products increase the
performance of IP over satellite through
a combination of protocol connection-
splitting, data compression.
The Sky X gateway works by transparently
replacing TCP connections from the
client and converting the data to Xpress
Transport protocol (XTP) for the hop
over the satellite link .
The Sky X system delivers the Web
objects to the Sky X gateway on the
client side of the satellite link where
they can be served locally when
requested by the browser, avoiding the
The sky X client/server system enhances
the performance of the internet and
private network access over satellite
XTP Protocol :
Xpress Transport Protocol (XTP) is a
transport layer protocol for high-speed
networks promoted by the XTP Forum
developed to replace TCP.
XTP provides protocol options for error
control, flow control, and multicast
Instead of separate protocols for each
type of communication, XTP controls
packet exchange patterns to produce
Characteristics of XTP :
1> Error control
2> flow Control
Multi-Packet Handshaking :
The scenario above depicts how XTP can
reliably set up a connection between two
user processes, transmit data, and close
the connection with a minimum of three
In this scenario, the source initially
transmits packet (A) . At the
destination the header is examined and
it is determined that the source wishes
to establish a connection
The packet's data are then queued for
transfer to the waiting destination user
After successfully transferring the
received data to the host, the
destination complies by sending control
packet (B) .
This packet acknowledges the receipt of
the data, and indicates that the
destination is also ready t o close the
On receiving packet (B), the sender
emits control packet ©, and closes its
side of the connection â€ thus completing
the three way handshake.
Sky x-Gateway :
The Sky X gateway works by intercepting
the TCP connection from the client and
converting the data to the XTP for
transmission over the satellite.
The Sky X gateway on the opposite side
of the satellite link translates the
data back to TCP for communication with
This architecture offers vastly improved
performance while remaining entirely
transparent to the end user and fully
compactable with the internet
No changes are required to the client
or server and all applications continue
to function without modification.
The SkyX Gateway XR10 is well suited to
networks with high latency, high bit
error and asymmetric links.
Designed as an remote device, it
performs best at maximum bandwidth with
a single, very large FTPâ€and supports an
industry-best number of simultaneous
sessions and connection turnover rate.
Used for Satellite communication.
Used for accessing web in fastest speed.
Used For data transfer, File Transfer
1> Increases web performance 3 times
2> Does not require any modifications to
end client and servers.
3>Sky X Gateway provides fast,
efficient, fully reliable multicast file
Future enhancement :
A product called XipLink which is under
developing will replace the Sky X.
It is very much the same as the Sky X
with extra capabilities.
It optimize all TCP/IP traffic,
basically the link itself.
Thus Sky -x technology is best suited
for for satellite communication using
XTP protocol and Sky x gateway.
The Sky X system of a satellite network
allows users to take full advantage of
the available bandwidth
It gives all features required for
successful data Transmission.
The Xpress Transfer Protocol (XTP) â€ A
Paper by Robert M. Sanders and Alfred C.
Weaver, University of Virginia
Research and Development of High-End
Computer Networks at GSFC . by J.
Patrick Gary. Earth and Space Data