Saturday, May 26, 2012

Steve Vs Dennis


                                                                                                                                          -shared from facebook

Wednesday, May 23, 2012

i3 vs i5 vs i7 – Intel Core Processors


i3 vs i5 vs i7 – Intel Core Processors
                hi friends here are some brief comparison of i3, i5 , i7 intel core processorsi3 vs i5
Specifications :

Product Name
Price
$124.99
$219.99
$299.99
# of Cores
2
4
4
# of Threads
4
4
8
Clock Speed
3.1 GHz
3.3 GHz
3.4 GHz
Max Turbo Frequency
n/a
3.7 GHz
3.8 GHz
Cache
3 MB
6 MB
8 MB
Bus/Core Ratio
31
33
34
System Bus
5 GT/s
5 GT/s
5 GT/s
Instruction Set
64-bit
64-bit
64-bit
Lithography
32 nm
32 nm
32 nm
Max TDP
65 W
95 W
95 W
Memory Specifications
Max Memory Size
32 GB
32 GB
32 GB
Memory Types
DDR3-1066/1333
DDR3-1066/1333
DDR3-1066/1333
# of Memory Channels
2
2
2
Max Memory Bandwidth
21 GB/s
21 GB/s
21 GB/s
Graphics Specifications
Processor Graphics
Yes
Yes
Yes
Graphics Model
Intel® HD Graphics 2000
Intel® HD Graphics 3000
Intel® HD Graphics 2000
Intel® Quick Sync Video
Yes
Yes
Yes
Intel® InTru™ 3D Technology,
Yes
Yes
Yes
Intel® Insider™
Yes
Yes
Yes
Intel® Wireless Display
No
No
No
Intel® Flexible Display Interface (Intel® FDI)
Yes
Yes
Yes
Intel® Clear Video HD Technology
Yes
Yes
Yes
Dual Display Capable
Yes
Yes
Yes
Expansion Options
PCI Express Revision
2.0
2.0
2.0
Advanced Technologies
Intel® Turbo Boost Technology
No
2.0
2.0
Intel® vPro Technology
No
No
Yes
Intel® Hyper-Threading Technology
Yes
No
Yes
Intel® Virtualization Technology (VT-x)
Yes
Yes
Yes
Intel® Virtualization Technology for Directed I/O (VT-d)
No
No
Yes
Intel® Trusted Execution Technology
No
No
Yes
AES New Instructions
No
Yes
Yes
Intel® 64
Yes
Yes
Yes
Idle States
Yes
Yes
Yes
Enhanced Intel SpeedStep® Technology
Yes
Yes
Yes
Thermal Monitoring Technologies
Yes
Yes
Yes
Intel® Fast Memory Access
Yes
Yes
Yes
Intel® Flex Memory Access
Yes
Yes
Yes
Execute Disable Bit
Yes
Yes
Yes
                                                                                                                -info collected from internet

Internet Download Manager


         Internet Download manager is one of the best software to youtube videos and to download the files from internet with many options.
         Internet Download Manager is a full-featured package that handles downloading tasks with aplomb. It conveniently integrates into your browser, even if you use Mozilla or Opera.
It automatically sorts incoming files by file type and puts them in the appropriate folder. Most importantly, it supercharges download speeds (it doubled ours). Its windowed interface is clean and easy to understand. Power users can take advantage of the command line interface to resume file transfers, schedule downloads, connect through dial-up, or log on to password-protected sites. Experienced users also can limit the number of connections, the download speeds for specific sites, and even create an exception list to block specific, user-defined sites.
         Other features include automatic virus checking and the ability to download all files linked to a page. The new version has a Web spider that can analyze a site and retrieve, for example, all the images on it.
Internet Download Manager strikes us as a natural choice for users in need of a trusty transfer tool. Version 5.11 build 5 added FLV grabber that can be used to download videos from YouTube, Google Video, MySpaceTV, and other popular sites.
                                                                                                                -resource from internet
click here to download free (trial verison)
click here to buy IDM


Tuesday, May 22, 2012

Windows 8 Minimum System Requirements


windows 8 system requirement
It is reported that Windows 8 is expected to have the same system requirements as Windows 7, and will run on existing machines that run Windows 7. Here are the following minimum system requirements to run Windows 8:

Processor: 1GHz or faster 32-bit or 64-bit processor

RAM: 1GB (32-bit) or 2GB (64-bit)

HD Space: 16GB for 32-bit (or 20GB for 64-bit)
                                                                                                          - data collected from other site

Sunday, May 6, 2012

A Modern Broadcast TV Experience - Ubuntu TV


As anticipated Canonical has finally demonstrated version of its popular Ubuntu Linux OS that can be used for running TVs at the Consumer Electronics Show 2012 Event. Presently, The company is displaying a prototype unit, called the Ubuntu TV.
Ubuntu TV offers easy integration of online and broadcast services, and applications, allowing users to search, record, buy, rent and playback.
With Ubuntu TV Users will not only be able to watch cable and over-the-air television shows, but, thanks to some built-in computational ability, also offer a user interface to allow viewers to pull video from the Internet, run applications and peruse channel guides more easily.

Canonical has plans to court manufacturers such as Sony and LG who can adopt Ubuntu as a base for their own smart television sets and to offer a wide range of processor-embedded consumer devices.
While Ubuntu TV is still in the development stage, we can expect lots of interesting products from Canonical in the year 2012

Icall call from pc to mobile phone


You may have heard of VOIP, or Voice Over IP before. Now there is a company called iCall that lets you make and receive phone calls from your computer to regular land lines. It works all over the U.S.

Click here to view their website and download the free software.

Saturday, May 5, 2012

Second Rescheduling of UG/PG Examinations Time Table( New Timetable) - Affiliated Colleges May/June 2012 & Changes and Additions - III for regulation 2004 2007 2008 in Anna University, Chennai & Anna University of Technology, Tirunelveli



                                                                                                                                    Date: 4/5/2012 
 NEW NOTIFICATION ON SECOND RESCHEDULING OF EXAM DATES FOR 
AFFILIATED COLLEGES MAY/JUNE 2012 EXAMINATIONS
        As per the original Time Table given, Anna University Theory Examinations for Affiliated Colleges, Constituent Colleges and University Departments of Anna Universities of Technology (AUTs) (May/June 2012) were to commence on 3.5.2012. But due to administrative reasons, the examinations on 3rd, 4th, 5th May 2012 were rescheduled on 28th, 29th and 30th May 2012 and the examinations on 28th, 29th and 30th May 2012 were rescheduled on 7th, 8th, and 9th June 2012.

Now all the examinations starting from 7.5.2012 are rescheduled again shifting by exactly 7 days. The detailed list is given below:            





Tuesday, May 1, 2012

SKY X TECHNOLOGY abstract with full paper and ppt


SKY X TECHNOLOGY
Abstract
              Satellites are attractive option for carrying internet and other IP traffic to many locations across the globe where terrestrial options are limited or [censored] prohibitive. But data       networking on satellite is faced with overcoming the large latency and high bit error rate typical of satellite communications as well as the asymmetric bandwidth design of most satellite network. 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. So the throughput over the satellite networks is restricted to only a fraction of available bandwidth, the leading supplies of TCP/IP to the computer industry have overcome their limitations with the development of the Sky X product family.
The Sky X system replaces TCP over satellite link with a protocol optimized for the long latency, high loss and asymmetric bandwidth conditions of the typical satellite communication. The Sky X family consists of Sky X Gateway, Sky X Client/Server and Sky X OEM products. Sky X products increase the performance of IP over satellite by transparency replacing. The Sky X Gateway works by intercepting the TCP connection from client and converting the data to Sky X protocol for transmission over the satellite. The Sky X Client /Server product operates in a similar manner except that the Sky X client software is installed on each end users PC Connection from applications running on the PC is intercepted and send over the satellite using the Sky X protocol.

FULL PAPER

Abstract
Satellites are attractive option for carrying internet and other IP traffic to many locations across the globe where terrestrial options are limited or [censored] prohibitive. But data       networking on satellite is faced with overcoming the large latency and high bit error rate typical of satellite communications as well as the asymmetric bandwidth design of most satellite network. 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. So the throughput over the satellite networks is restricted to only a fraction of available bandwidth, the leading supplies of TCP/IP to the computer industry have overcome their limitations with the development of the Sky X product family.
The Sky X system replaces TCP over satellite link with a protocol optimized for the long latency, high loss and asymmetric bandwidth conditions of the typical satellite communication. The Sky X family consists of Sky X Gateway, Sky X Client/Server and Sky X OEM products. Sky X products increase the performance of IP over satellite by transparency replacing. The Sky X Gateway works by intercepting the TCP connection from client and converting the data to Sky X protocol for transmission over the satellite. The Sky X Client /Server product operates in a similar manner except that the Sky X client software is installed on each end users PC Connection from applications running on the PC is intercepted and send over the satellite using the Sky X protocol.

Seminar by:                                                    Guided by:


 

Contents                                                             Page no.

1.      Introduction                                                                                      
  1. Performance of TCP over satellite                                                                         
  2. Window size                                                                                    
  3. Congestion Avoidance
  4. SKY X SYSTEM
  5. SKY X GATEWAY OPERATION
  6. Sky X Client/Server
  7. Sky X Multicast Fan-Out
  8. Sky X Performance
  9. SKY X PROTOCOL DESIGN
  10. Sky X OEM (Original Equipment Manufacturer)
  11. Sky X Accelerator    
  12. Conclusion                                                                                        
  13. References                                                                



                                                                                         





INTRODUCTION

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. We can overcome these restrictions by using the Sky X protocol.
The Sky X Gateway and Sky X Client/Servers systems replaces TCP over satellite link with a protocol optimized for the long latency, high loss and asymmetric 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 Gateway transparently enhances the performance of all users on a satellite network without any modifications to the end clients and servers. The Sky X Client and the Sky X Server enhance the performance of data transmissions over satellites directly to end user PC’s, thereby  increasing 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

Sky X products are the leading implementation of a class of products known variously as protocol gateway TCP Performance Enhancing Proxy (TCP/PEP) , or satellite spoofer.The Sky X gateways are available as ready to install hardware solutions which can be added to any satellite network.
The Sky X family consists of the Sky X Gateway, Sky x Client/Server and the sky X OEM products. The Sky X Gateway is a hardware solution designed for easy installation into any satellite network and provides performance enhancement for all devices on the network. The Sky X Client/Server provides performance enhancement to individual PC’s.
A.   PERFORMANCE OF TCP OVER SATELLITE
Satellites are an attractive option for carrying Internet and other IP traffic to many locations across the globe where terrestrial options are limited or price prohibitive. However data networking over satellites is faced with overcoming the latency and high bit error rates typical of satellite communications, as well as the asymmetric bandwidth of most satellite networks
Communication over geosynchronous satellites, orbiting at an altitude of 22,300 miles has round trip times of approximately 540 m/s, an order of magnitude larger than terrestrial networks. The journey through the atmosphere can also introduce bit errors into the data stream. These factors, combined with backchannel bandwidth typically much smaller than that available on the forward channel, reduce the effectiveness of TCP which is optimized for short hops over low-loss cables or fiber. Even though the TCP is very effective in the local network connected by using cables or optical fibers by using its many features such as LPV6, LPsec and other leading-edge functionality. Also it will work with real time operating systems.TCP is designed for efficiency and high performance ,and optimized for maximum throughput and the highest transaction speeds in local networks.
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 satellite link. The adverse effects of using TCP over satellite link in its various features are as follows:
B.   Window size
TCP utilizes a sliding window mechanism to limit the amount of data in flight. When the window becomes full, the sender stops transmitting until it receives new acknowledgement. Over satellite networks, where acknowledgements are slow to return, the TCP window size gradually sets a hard limit on the maximum throughput rate. The minimum window size needed to fully utilize an error-free link known as the “bandwidth-delay product” is 100 KB for a T1 satellite link and 675 KB for a 10 Mbps link. However many implementations of TCP are limited to maximum window size of 64 KB and most operating systems use a default window size of only 8 KB , imposing a maximum throughput rate over a satellite link of only 128 Kbps per connection , regardless of the bandwidth available. So the high bandwidth available in the network is no longer effective, thus the data availability in a client is restricted to a small fraction of the available bandwidth. Thus the window sizing mechanism of the TCP limits the rate of flow of data through satellite link.
The simple, heuristic data acknowledgment scheme used by TCP does not adapt well to long latency or highly asymmetric bandwidth conditions. To provide reliable data transmission, the TCP receiver constantly sends acknowledgments back to the sender. The sender does not assume that any data is lost or corrupted until a multiple of the round-trip time has passed without receiving an acknowledgment. This algorithm does not respond well over satellite networks where the round-trip time is long and error rates can be high. Further, this constant stream of acknowledgments wastes precious back channel bandwidth and if the back channel is small, the return of the acknowledgments to the sender can become the system bottleneck. The acknowledgements and error messages will always dominate the data transfer and the rate of flow reduces very much.
C.   Congestion Avoidance
In order to avoid the possibility of congestive network meltdown, TCP usually assumes that all data loss is caused by congestion and responds to this by reducing the transmission rate. However, over satellite links, TCP misinterprets the long round-trip time and bit errors as congestion and responds inappropriately. Similarly, the TCP “Slow Start” algorithm, which over the terrestrial infrastructure prevents new connections from flooding an already congested network, forces an excessively long ramp-up period for each new connection over satellite. While these congestion avoidance mechanisms are vital in routed environments, they are ill-suited to single-path satellite links.
So the congestion avoidance mechanisms used by TCP is also not suited for the satellite link since it reduces the data flow through the network and thus reduces the overall rate of data transfer.
SKY X SYSTEM
Sky X Technology Overcomes TCP Performance Limitations
Sky X products increase the performance of IP over satellite through a combination of protocol connection-splitting, data compression, and Web pre-fetching, while remaining entirely transparent to end users. 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 which is the protocol optimized for satellite conditions.
A.   SKY X GATEWAY OPERATION
The Sky X gateway works by intercepting the TCP connection from the client and converting the data to the Xpress Transport Protocol (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 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. This architecture is also referred to as TCP Performance Enhancing Proxy (TCP-PEP) and is compactable with IETF RFC 3135.
The Sky X gateway splits the single TCP connection into three separate components. A TCP connection on the remote side between the client and Sky X gateway, an XTP connection involving Sky X protocol over the satellite between the two Sky X gateways and a TCP connection between the opposite Sky X gateway and server.
XTP is a reliable, transport-layer protocol specifically designed to operate efficiently over high-speed networks and offers a level of performance not possible with TCP on long latency, high loss satellite links. XTP is an open standard developed by the XTP Forum, a non-profit organization composed of networking protocol researchers, implementers, and user organization
By splitting the end-to-end TCP connection, the segment over the satellite can take advantage of the performance of XTP. TCP congestion avoidance mechanisms remain in place over the terrestrial connections to protect the stability of the routed network. The two Sky X gateways pass control data between each other, allowing the Sky X gateway on the opposite side of the satellite to appear to be the original source or destination device. This architecture maintains full TCP reliability and end-to-end flow control.
Web Pre-Fetch functionality further enhances the performance of HTTP transfers over the satellite link by pro-actively retrieving the many embedded objects on a Web page along with the requested HTML page. 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 satellite delay.
The Sky X gateway XR10, XH45, and XH155 are available as ready-to-install hardware solutions which can be added to any satellite network. The Sky X Client software installs directly on the PCs of end-users and works in conjunction with a Sky X Server SS10 or SS45 hardware unit located at the network hub. Mentat also licenses the Sky X gateway technology in software source code form for integration with satellite modems, VSATs, routers, caching systems, or any other satellite connectivity equipment. The Sky X gateway can also be used in multilink configurations where a single Sky X gateway hub unit enhances the performance of multiple separate outbound links from a single uplink facility.
Mentat SkyX Gateway 250 - gateway (discontinued)
Mentat SkyX Gateway 250 - gateway
Manufacturer description
The SkyX 250 is ideal as a remote, or hub, device to bring high network performance to lower bandwidth networks. Also use at both sides of the link in a point-to-link as well as in fully meshed networks

The Sky X Client / Server product operates similarly to the Sky X gateway except the Sky X Client software is installed directly onto the client PC. Connections from applications running on the PC are intercepted and sent over the satellite using Sky X protocol. At the network hub, a Sky X Server establishes a TCP connection with the destination server.
B.   Sky X Client/Server
The Sky X Client / Server increases the throughput and efficiency of network access over satellites by transparently replacing TCP with the Xpress Transport Protocol (XTP) for the satellite segment of the connection. Combined with data compression and Web-specific enhancements, the Sky X system provides maximum performance under the long latency, high loss, and asymmetric bandwidth conditions typical of satellite communications.
The sky X client/server system enhances the performance of the internet and private network access over satellite links. The sky X client software installed on the PC’s of the end user, works in conjunction with a sky X server hardware unit located at the network hub. Through the use of a unique connection splitting and protocol –translation system, the sky X client/server system overcomes the deficiencies of TCP/IP in satellite –based networks while remaining entirely transparent to end-user applications. The sky X client is ideal for use with any satellite receiver card or set –top box
Sky X Client / Sky X Server Operation
The Sky X Client / Server increases the throughput and efficiency of network access over satellites by transparently replacing TCP with the Xpress Transport Protocol (XTP) for the satellite segment of the connection. Combined with data compression and Web-specific enhancements, the Sky X system provides maximum performance under the long latency, high loss, and asymmetric bandwidth conditions typical of satellite communications.

The Sky X Client, installed on Microsoft Windows-based computers, transparently intercepts TCP connections from applications running on the PC and transmits the data over the satellite link using XTP. The Sky X Server, installed at the hub of the satellite network, establishes a new TCP connection for communication with any device on the local network or over the Internet. Through this unique, patented architecture, the Sky X Client / Server system requires no proxy settings while providing performance enhancement for all TCP applications.
The Sky X Server is available in two models namely the SS10 and SS45. The SS10 provides Sky X enhancement for links of up to 10 Mbps while the SS45 provides Sky X enhancement for links of up to 45 Mbps

Sky X Multicast Fan-Out
Computer networking traditionally relies on unicast data transfers which establish point-to-point connections between devices. In situations where the same data is transferred to multiple users, the server must send a copy of the file to each recipient independently. This process is both time consuming and wastes much of the bandwidth resources.
In contrast, multicast technology makes it possible for multiple recipients to receive a single data stream. This can be an especially powerful tool for satellite networks or similar architectures where the multicast transfer can take advantage of an underlying link layer broadcast media. Unfortunately, the only multicast capability built into the Internet Protocol is a UDP-based, unreliable, best-effort service that is only appropriate for real-time streaming applications such as event broadcasting. Because UDP-based IP multicast does not include any mechanisms for detection and retransmission of lost or corrupted data and does not resequence any packets that arrive out of order, IP multicast is not suitable for file downloads and other data transfer applications.  Sky X Multicast Fan-Out offers a simple and convenient solution for reliable multicast over wide area networks. By taking advantage of reliable multicast functionality built directly into XTP, the open-standard transport-layer protocol used by the Sky X Gateway to transfer data over the WAN link, the Sky X Gateway provides fast, efficient, fully reliable multicast file transfers. Any data that is lost or corrupted is retransmitted, providing transfer reliability and rendering special FEC software unnecessary.
The Sky X multicast fanout, an integral component of the Sky X gateway, transparently converts TCP unicast connections into reliable multicast transfers. Through the use of common TCP based applications such as FTP, the Sky X gateway can deliver a file to every remote location across a wide area network with only a single multicast transfer. Sky X multicast fanout is built on the industry leading Sky X gateway IP over satellite performance enhancement system. Because the Sky X multicast fanout process is transparent to the end devices , any machine can originate or receive the multicast transfer regardless of operating system and without requiring the installation of any specialized multicast software.
By combining this reliable multicast transmission technology with a transparent fanout functionality which allows any TCP connection to be converted into a multicast transfer, the Sky X gateway marries the power of multicasting with the convenience of using FTP or any other TCP-based application. In addition to the multicast benefits themselves, the Sky X gateway includes on-the-fly data compression which further increases transfer speeds for compressible data by up to 5 times.  Sky X multicast fanout functionality is ideal for file transfers, cache replication, video file distribution, content delivery networks, database replication, and any other distribution of data or files to multiple users over a satellite link or other wide area network.
Sky X Performance
The performance benefits of the sky X gateway depend on many factors including the bandwidth, delay, asymmetry and bit error rate of the link, the number of simultaneous connections, the compressibility of the data and the behavior of the application itself. Below are data for two typical applications across a range of conditions File Transfers
The following file transfer tests illustrate the benefits of Sky X performance enhancement for different windows sizes, link band-widths, round-trip times, and bit error rates. Users should expect similar results for any large, single-connection data transfer. Each graph shows Sky X enhancement for three cases: no compression, highly compressible text, and Corpus benchmark compressibility
1.     Window Size and Link Speed vs. Throughput
40Without performance enhancement, a default window size of 8 KB limits TCP throughput to less than 100 Kbps over satellite.  As the graph on the left illustrates, even on server operating systems using a 32 KB window, TCP is only able to reach a through-put of 440 Kbps. Sky X gateway overcomes this limitation, taking full advantage of the available bandwidth regardless of the window size of the client or server. For compressible data, Sky X can provide throughput rates far greater than the link bandwidth.

2.     Round-Trip Delay vs. Throughput
The Sky X gateway system removes the dependency of TCP on the round-trip time of the link. The figure below shows the measured throughput on an error-free, 10 Mbps link. These results illustrate that TCP throughput drops rapidly as the round-trip time increases. In contrast, Sky X is able to maintain full usage of the link regardless of the round-trip time. For compressible text, Sky X consistently delivers throughput rates greater than the actual bandwidth.

3.    Bit Error Rate vs. Throughput
The Sky X system overcomes the high sensitivity of TCP to the bit error rate of the link. The graph given below shows the throughput as a function of the bit error rate for a 10 Mbps satellite link using a 1 MB TCP window. Even at low error rates, TCP is able to deliver only 1.5 Mbps, while at an error rate of 1×10-5, TCP’s throughput drops to less than 0.03 Mbps. Sky X fully saturates the link at low error rates and even at an error rate of 1×10-5, achieves 5.1 Mbps without compression and up to 15.8 Mbps for compressible data.

4.    Web Performance

Unlike file transfers which typically consist of a single, large download, Web traffic is characterized by large numbers of short connections. Mentat’s innovative Fast Start feature specifically optimizes Web performance by reducing time required to establish new connection. The Web stone HTTP benchmark shows that for an 8  Mbps error-free link, the average response time for a mixture of 50 simultaneous web connections using the sky X gateway is between 0.7 and 1.1 seconds depending on the compressibility of the data, compared to 3.0 seconds with TCP.
Other Applications
Performance benefits from applications other than Web and file transfers depend on the characteristics of the application, but will typically fall between these two extremes. Sky X gateway has been tested by many organizations and various independent third parties for a wide variety of different conditions and has been found satisfactory .Sky X gateway can also simulate link speed bit error rate and delay conditions of the existing system on the sky X gateway test network


SKY X PROTOCOL DESIGN
At the heart of the Sky X system is the Sky X protocol, optimized to provide maximum throughput for satellite networks. The Sky X protocol is designed to respond efficiently to typical satellite latency, bit errors and asymmetric bandwidth conditions and to take advantage of optimizations possible on a single-path link with known bandwidth. The Sky X gateway combines protocol, application and system level enhancements to provide maximum throughput for satellite networks.
1.     Efficient Acknowledgment Algorithm
The Sky X Protocol utilizes a highly efficient selective retransmission algorithm for the acknowledgment of data. Because there is only a single path over the satellite with no intermediate routing, any gaps in the packet sequence can be assumed to be data loss due to corruption rather than network congestion. The receiving Sky X gateway can immediately request and receive retransmission of the missing data from the transmitting Sky X gateway. Because the Sky X Protocol does not use acknowledgments as the primary means of identifying lost data, it requires only infrequent acknowledgments to confirm data arrival and clear buffers. In contrast, TCP sends a constant stream of acknowledgments over the reverse channel.
The sky X Protocol reduces back channel usage by 75% for Web traffic and up to 99% for file transfers, thereby dramatically increasing the performance of networks where limited back channel bandwidth is the system bottleneck.
2.     Dynamic Window Sizing
The large Sky X Protocol window removes the dependency of the network on the bandwidth-delay product, allowing high throughput independent of the TCP window size of the end nodes. The Sky X Protocol dynamically adjusts the window size based on the link bandwidth, delay, and number of simultaneous connections to optimize utilization of the bandwidth.
Rate Control
TCP uses Slow Start and Congestion Avoidance algorithms to determine a safe transmission rate based on how quickly acknowledgments return. This wastes available bandwidth when it transmits at too low a rate, and causes unnecessary retransmissions when it transmits at a rate higher than the bandwidth of the link. Instead, the Sky X gateway uses a rate control mechanism to explicitly set the transmission rate to exactly the bandwidth of the link, thereby providing the maximum throughput possible at all times.

Web Prefetch
The Sky X system further enhances the performance of HTTP over the satellite link by proactively retrieving the many embedded objects on the web page along with requested HTML page. The Sky X system delivers the web objects to the client side of the satellite link where they can be served locally when requested by the browser ,there by avoiding satellite delay.
Fast Start Web Acceleration
In addition to TCP performance enhancement, Sky X products include HTTP specific optimizations to further accelerate web downloads. Fast Start saves one full round trip time for each new web connection by reducing the handshaking required to establish each new HTTP connection.
Data Compression
Integrated on-the-fly data compression functionality, offering lossless compression ratios of up to 5:1, increase4s the amount of data that can be sent over the link.
Sky X Multicast Fan-Out
The Sky X FTP multicast facility is designed to provide multicast fan-out functionality tailored specifically for use with FTP, combining the power of multicasting with the convenience of the well-known and ubiquitous FTP utility. The unique Sky X multicast Fan-Out facility can transparently convert a TCP unicast connection into a reliable multicast transfer .Using standard file transfer applications such a FTP the Sky X gateway can deliver a copy of a file to every remote site with only a single transfer.
C.   Sky X OEM (Original Equipment Manufacturer)
Mentat ( U.S company) licenses its Sky X gateway technology in software source code form for OEM integration into satellite modems, VSAT’s, routers, cache or  any other satellite networking equipment. The Sky X OEM software is available for various computer and real time operating systems.

Packeteer SkyX

 Packeteer Introduces New SkyX Accelerators for Improved TCP-Based Application Performance; New SkyX Accelerators Support Expanded Range of Link Speeds; Comply with European Restriction of Hazardous Substances Directive
CUPERTINO, Calif. -- Packeteer(R) (NASDAQ:PKTR), the global leader in WAN Application Optimization, today announced the introduction of two new SkyX Accelerator models based on new hardware platforms that provide substantially improved scalability to support future features and functional enhancements. Packeteer's SkyX Accelerators improve TCP-based application performance including SAP, FTP file transfers, e-mail and Web access. The appliances also provide acceleration capabilities for disaster recovery, database synchronizations and backups in high-latency, high-bandwidth environments such as satellite or datacenter-to-datacenter links.
The new SkyX 250 and high-end SkyX 750 Accelerators support a greater range of link speeds and concurrent sessions than their predecessors and utilize the new release 7.0 operating software that supports an Ethernet failover bypass capability while maintaining complete backward compatibility with existing SkyX appliances.
The SkyX 250 Accelerator also complies with the European Union (EU) Restriction of Hazardous Substances (RoHS) directive that is a requirement for all companies selling within or into the EU. The RoHS directive, designed to provide environmental safeguards eliminating the use of toxic materials, applies to electrical and electronic products and their components offered for sale in the EU after July 1, 2006. The RoHS-compliant version of the SkyX 750 is scheduled for availability later this year.
"Enterprises are quickly realizing that the ability to accelerate TCP-based applications provides a distinct competitive advantage through improved productivity, and that adding expensive bandwidth to compensate for poor WAN application performance is a failed strategy," said David Puglia, Packeteer's vice president of marketing. "The introduction of our new SkyX products will help customers accelerate host or client traffic, as well as improve the performance of strategic data center replication without having to implement link speed upgrades."
New SkyX Accelerator Details
The new SkyX Accelerators will be added to the Packeteer product line as the current XR10, XH45 and XH155 appliances are phased out. The SkyX 250 Accelerator is a 1U rack-mountable appliance that supports up to 20,000 concurrent sessions and accepts 45 Mbps of inbound traffic for compression. The system supports link speeds ranging form 2 - 45 Mbps. The high end SkyX 750 Accelerator is also a 1U rack mountable appliance capable of supporting up to 80,000 concurrent sessions and accepts 45 Mbps of inbound traffic for compression. Link speed options range from 10 - 155 Mbps.
Price and Availability
The SkyX 250 Accelerator is available now. A non-RoHS version of the SkyX 750 Accelerator is scheduled for availability in late August 2006; the RoHS-compliant version of the SkyX 750 Accelerator is scheduled for availability in late October 2006. Pricing for the SkyX 250 appliance starts at $2,500. Pricing for the SkyX 750 appliance starts at $10,000.
About Packeteer
Packeteer, Inc. (NASDAQ:PKTR), is the global market leader in WAN Optimization and Application Traffic Management for wide area networks. Deployed at more than 7,000 companies in 50 countries, Packeteer solutions empower IT organizations with patented network visibility, control, and acceleration capabilities delivered through a family of intelligent, scalable appliances. For more information, contact Packeteer at 1 (408) 873-4400 or visit the company's website at www.packeteer.com.
Safe Harbor Clause
The statements contained in this press release that are not purely historical are forward-looking statements within the meaning of Section 21E of the Securities and Exchange Act of 1934, as amended, including statements regarding Packeteer's expectations, beliefs, intentions or strategies regarding the future. Forward-looking statements include, but are not limited to, express or implied statements regarding future revenues, revenue growth and profitability, spending levels by existing and prospective customers, the markets for our products, new product development, liquidity and macro economic conditions. All forward-looking statements included in this press release are based upon information available to Packeteer as of the date hereof. Packeteer assumes no obligation to update any such forward-looking statements. Forward-looking statements involve risks and uncertainties, which could cause actual results to differ materially from those projected. Actual results may differ materially due to a number of factors including the perceived need for our products, our ability to convince potential customers of our value proposition, the costs of competitive solutions, continued capital spending by prospective customers and macro economic conditions. These and other risks relating to Packeteer's business are set forth in Packeteer's Form 10-K filed with the Securities and Exchange Commission on March 16, 2006, and Packeteer's Form 10-Qs and other reports filed from time to time with the Securities and Exchange Commission.

SkyX Accelerator
When TCP protocol design limitations, high latency and lost packets threaten application connection speed, SkyX Accelerator ramps flow, fully utilize links and keeps data moving along.


Accelerate file transfers, large and small
Speed XML and HTTP sessions, disaster recovery, database sync and backups
Optimize application performance over high-latency and satellite links
Increase link utilization on fat WAN links
Maximize bandwidth utilization and ROI
Minimize retransmission and recover more quickly from errors
TCP Acceleration
Enjoy faster database connectivity, Web and remote-access applications while maintaining full TCP reliability and end-to-end flow control. Specifically optimized for long delay, high bit error and asymmetric bandwidth conditions. Accelerate all TCP-based applications—including Web access, FTP file transfers, ERP and e-mail.
Data Center Replication Acceleration
SkyX Accelerator technology overcomes latency effect on TCP over high-bandwidth links by using bandwidth much more efficiently and improving replication performance over high capacity data center-to-data center links. Replication sessions complete up to 100 times faster and are not subject to the stalls and session drops associated with packet loss.
XML and Web Acceleration
Response times improve dramatically with enhanced HTTP performance. Sky X XpressWeb and XpressXML technology speeds delivery of embedded objects in Web-based applications. Further accelerate Web downloads by reducing time needed to establish each new HTTP connection.
           

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CONCLUSION
The sky X gateway is the leading solution for overcoming the limitations of TCP/IP over satellite. ISP’s, corporations, governments, and military organizations around the world rely on sky X gateway to enhance the performance of their satellite networks.
Testing by independent third parties including INTELSAT and NASA confirms that the sky X Gateway dramatically improves performance for the internet and private access over satellite networks.
The world is reducing to a global village by the use of satellite communication and so the improvement in the rate of information interchange through satellite is a must and thus sky X technology becomes unavoidable.

REFERENCES
BOOKS         
A Top Down Approach Featuring The Internet,
Addison Wesley by JF&Ross KW.
TCP/IP Protocol Suite, by B. Forouzan
Computer Networks A.Tanenbaum


 
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