28-01-2011, 04:21 PM
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zAfter successfully transferring the received data to the host, the destination complies by sending control packet (B) .
Introduction :
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 page link with a protocol optimized for the high loss and bandwidth conditions of the typical satellite communication.
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 servers.
Why sky X-Technology???
WORKING :
Sky X Technology Overcome TCP Performance Limitations.
Even though the TCP is very effective in the local network connected by using cables or optical fibers by using its many features
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 satellite link.
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 page link .
The Sky X system delivers the Web objects to the Sky X gateway on the client side of the satellite page link where they can be served locally when requested by the browser, avoiding the satellite delay.
The sky X client/server system enhances the performance of the internet and private network access over satellite links
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 mode.
Instead of separate protocols for each type of communication, XTP controls packet exchange patterns to produce different models.
Characteristics of XTP :
1> Error control
2> flow Control
3>Byte ordering
4>Prioritization Issues
5>Multicast mode
6>Selective Retransmission
7>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 packets .
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 process .
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 connection.
On receiving packet (B), the sender emits control packet ©, and closes its side of the connection — 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 page link translates the data back to TCP for communication with the server.
This architecture offers vastly improved performance while remaining entirely transparent to the end user and fully compactable with the internet infrastructure.
No changes are required to the client or server and all applications continue to function without modification.
Application :
Used for Satellite communication.
Used for accessing web in fastest speed.
Used For data transfer, File Transfer efficiently.
Merits :
1> Increases web performance 3 times faster.
2> Does not require any modifications to end client and servers.
3>Sky X Gateway provides fast, efficient, fully reliable multicast file transfers.
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 page link itself.
Conclusion :
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.
