Toshiba portable hard drive with 320 GB and 500 GB:

An amazing invention that allows you to store data and also computer systems can easily customize the frequency, adjust the level of security

It is from Toshiba Thailand Co., Ltd. That introduces 2.5-inch hard drive, portable 320 GB capacity and 500 GB allows you to store both computer data can easily customize the frequency, adjust the level of security. And types of files saved. A security password. In addition, detection technologies in shock and preventing damage to the movement of data in the drive. Users confidence in the security of data stored on the hard drive, Toshiba. Toshiba trusted for over 20 years of manufacturing hard drives. To use all the brand name notebook computers.

For your interest is to choose c Waa New capacity 500 GB and 320 GB Price 3,790 Baht 2,650 Baht price (price including VAT) in many varied colors such as white and want mail clearly be beautiful, elegant blue, green and red dragon force ineffective. www.toshiba.co.th.

What is HUB and how it works::

Workings of this tool is to send signals to the entire data packet to the hub ports so that data packets received by all computers connected to the hub unless the sending computer. Sent the signal to be repeated, although the data packet has been received by the destination computer. This causes the function colossion more often when there terjadi.Misalnya delivery of data packets port A to port B and at the same time there is transmission of data packets from port C to port D, there will be collisions (collision) Because it uses the same line (line broadcast the same) so that the data packet will be corrupted causing repeated transmission of data packets. If this happens then Collison which happens to disrupt the activities of sending new data packets or replay. This resulted in a decrease of data transfer speed. Therefore, physically, hub a lamp led which indicates there collision.
When the data packet is sent through one port on hub, Then sending the data packet will be seen and sent to each port other so bandwidth on hub be divided into the port available. More port available at hub, Then bandwidth are available to be smaller for each port.
This makes the data transmission hub with many ports that are connected to the computer slows down.

Nokia New Amazing X6 Launched:

Amazing Nokia has redefined the music. It latest launched x6 and x3 the next generation music mobiles. Nokia x6 is a powerful music mobile with 3.2 inch finger touch screen, whooping 32 GB built in memory and aspect ratio of 16:9.

The music is the major attraction in this stylish gadget with continuous playback of 35 hours. A 5-megapixel camera and Carl Zeiss lens will be like camera on go. The screen was optimized for photos, videos and internet. It brings social networking communities like Face-book and allows 20 friends on virtual community called Life-casting.
Overall this device takes music in a new dimension.

Wireless Communications:

The cellular revolution is apparent in the growth of the mobile phone market. Mobile communication includes cellular personal communication systems, personal communication networks, land mobile and mobile satellite radio systems. In 1930s all mobile radio used were using amplitude modulation. In 1935, frequency modulation was used. The first generation of wireless communication is angular cellular system. The second generation of wireless communication is digital cellular system. The third generation of wireless communication is based on CDMA as the multiple access technology. Wireless network topology is the configuration in which mobile terminals communicate with another. Mobile radio transmission system may be classified as simplex, half duplex and full duplex. The important terms in wireless communication are base station, control channel, forward channel, half hand mobile station, mobile switching center, page, reverse channel, frequency division multiplexing and time division multiplexing. The examples of wireless communication are paging system, cordless telephone systems and cellular telephone systems. Some of the common wireless communication systems are TV remote control, garage door opener, paging system, cordless phone and cellular phone. A device which is capable of simultaneously transmitting and receiving operation is known as transceiver. Later on global system for mobile, digital European cordless telephone, CDMA digital cellular standard, advance mobile phone service, 3G wireless networks, Bluetooth, etc are introduced in wireless communication.

Satellite Communications:

Satellite communications are originally developed to provide long distance telephone service. Nowadays it has become an essential part of the world’s telecom communication system. By use of this satellite communication they serve billions of people with telephone, data as well as video services. It is also used for remote sensing like detection of water pollution, monitoring and reporting of weather conditions. In satellite service provided by satellite communication are fixed satellite service, broadcasting satellite service, mobile satellite service, navigational satellite service and meteorological satellite services. The most important satellite systems are INTELSAT, USDOMSAT AND US National Oceanographic and Atmospheric administration services of polar orbiting satellites. Geostationary orbit is an orbit in which a satellite appears to be stationary with respect to the earth. Satellite communication is classified into two segments. They are ground segment and space segment. The space segment includes tracking telemetry & command, power subsystem, attitude control system, orbital control system, thermal control system, transponders, etc. The ground segment includes stations on ship at sea, aeronautical mobile stations, home TV receives only system, commercial and military land systems. The satellite operation can be divided into two access modes. They are single access mode and multiple access modes. Recently broadcasting directly to home TV receiver using satellite is introduced which is known as Direct Broad Satellite (DBS) service.

Networks Essential:

A network is a combination of hardware and software that sends data from one location to another location. The layers of the network are higher layer, middle layer and lower layer. These layers are present in both sender section as well as receiver section. Each layer at the sending side uses the services of the layer immediately. The open system interconnection (OSI) model is the ultimate standard for data communication. The international standard organization (ISO) is a multinational body decided to worldwide agreement on international standards. The OSI model was first introduced in the late 1970s. The purpose of the OSI model is to show how to facilitate communication between different systems without requiring changes to the logic of the underlying hardware and software. It consists of seven separate but related layers. The seven layers of OSI model are physical layer, data link layer, network layer, transport layer, session layer, presentation layer and application layer. The TCP/IP protocol suite was developed prior to the OSI model. The original TCP/IP protocol suite has four layers. They are host to network layer, internet layer, transport layer and application layer. They are four types of addresses used in an internet employing. They are physical addresses, logical addresses, port addresses and specific addresses. These are the general idea about the layers of a network and its function.

Applications and Netwrok Address Translation::

Some Application Layer protocols (such as FTP and SIP) send explicit network addresses within their application data. FTP in active mode, for example, uses separate connections for control traffic (commands) and for data traffic (file contents). When requesting a file transfer, the host making the request identifies the corresponding data connection by its network layer and transport layer addresses. If the host making the request lies behind a simple NAT firewall, the translation of the IP address and/or TCP port number makes the information received by the server invalid. The Session Initiation Protocol (SIP) controls Voice over IP (VoIP) communications and suffers the same problem . SIP may use multiple ports to set up a connection and transmit voice stream via RTP. IP addresses and port numbers are encoded in the payload data and must be known prior to the traversal of NATs. Without special techniques, such as STUN, NAT behavior is unpredictable and communications may fail.
Application Layer Gateway (ALG) software or hardware may correct these problems. An ALG software module running on a NAT firewall device updates any payload data made invalid by address translation. ALGs obviously need to understand the higher-layer protocol that they need to fix, and so each protocol with this problem requires a separate ALG.
Another possible solution to this problem is to use NAT traversal techniques using protocols such as STUN or ICE or proprietary approaches in a session border controller. NAT traversal is possible in both TCP- and UDP-based applications, but the UDP-based technique is simpler, more widely understood, and more compatible with legacy NATs. In either case, the high level protocol must be designed with NAT traversal in mind, and it does not work reliably across symmetric NATs or other poorly-behaved legacy NATs.
Other possibilities are UPnP (Universal Plug and Play) or Bonjour (NAT-PMP), but these require the cooperation of the NAT device.
Most traditional client-server protocols (FTP being the main exception), however, do not send layer 3 contact information and therefore do not require any special treatment by NATs. In fact, avoiding NAT complications is practically a requirement when designing new higher-layer protocols today.
NATs can also cause problems where IPsec encryption is applied and in cases where multiple devices such as SIP phones are located behind a NAT. Phones which encrypt their signaling with IPsec encapsulate the port information within the IPsec packet meaning that NA(P)T devices cannot access and translate the port. In these cases the NA(P)T devices revert to simple NAT operation. This means that all traffic returning to the NAT will be mapped onto one client causing the service to fail. There are a couple of solutions to this problem, one is to use TLS which operates at level 4 in the OSI Reference Model and therefore does not mask the port number, or to Encapsulate the IPsec within UDP - the latter being the solution chosen by TISPAN to achieve secure NAT traversal.
The DNS protocol vulnerability announced by Dan Kaminsky on 2008 July 8 is indirectly affected by NAT port mapping. To avoid DNS server cache poisoning, it is highly desirable to not translate UDP source port numbers of outgoing DNS requests from any DNS server which is behind a firewall which implements NAT. The recommended work-around for the DNS vulnerability is to make all caching DNS servers use randomized UDP source ports. If the NAT function de-randomizes the UDP source ports, the DNS server will be made vulnerable.

Network Address Translation (NAT):

In computer networking, network address translation (NAT) is the process of modifying network address information in datagram packet headers while in transit across a traffic routing device for the purpose of remapping a given address space into another.
Most often today, NAT is used in conjunction with network masquerading (or IP masquerading) which is a technique that hides an entire address space, usually consisting of private network addresses (RFC 1918), behind a single IP address in another, often public address space. This mechanism is implemented in a routing device that uses stateful translation tables to map the "hidden" addresses into a single address and then rewrites the outgoing Internet Protocol (IP) packets on exit so that they appear to originate from the router. In the reverse communications path, responses are mapped back to the originating IP address using the rules ("state") stored in the translation tables. The translation table rules established in this fashion are flushed after a short period without new traffic refreshing their state.
As described, the method only allows transit traffic through the router when it is originating in the masqueraded network, since this establishes the translation tables. However, most NAT devices today allow the network administrator to configure translation tables entries for permanent use. This feature is often referred to as "static NAT" or port forwarding and allows traffic originating in the 'outside' network to reach designated hosts in the masqueraded network.
Because of the popularity of this technique, see below, the term NAT has become virtually synonymous with the method of IP masquerading.
Network address translation has serious consequences (see below, Drawbacks & Benefits) on the quality of Internet connectivity and requires careful attention to the details of its implementation. As a result, many methods have been devised to alleviate the issues encountered. See article on NAT traversal.

Some Questions and their Answer:

What is Broadband Internet Access?The term broadband refers to any type of transmission technique that carries several data channels over a common wire. DSL service, for example, combines separate voice and data channels over a single telephone line. In DSL, voice fills the low end of the frequency spectrum and data fills the high end.
In home networking, broadband constitutes any form of high-speed Internet access using this transmission technique. Both DSL and cable modem are common broadband Internet technologies. So-called broadband
The term "broadband" refers to a communications technique for transmitting multiple simultaneous data channels. Broadband is a popular form of high-speed Internet access.

What is Dial Up Internet Access?

Dial up networking technology provides PCs and other network devices access to a LAN or WAN via standard telephone lines. Dial up Internet service providers offer subscription plans for home computer users.
Types of dial up services include V.34 and V.90 modem as well as Integrated Services Digital Network (ISDN). Dial up systems utilize special-purpose network protocols like Point-to-Point Protocol (PPP).
To use a dial up Internet connection, a client modem calls another modem located at the Internet Service Provider (ISP). The modems transfer network information over the telephone until one modem or the other disconnects.
When the popularity of the Internet exploded in the 1990s, dial up was the most common form of Internet access due mainly to its low cost to setup. However, the performance of dial up networking is relatively poor due to the limitations of traditional modem technology. V.90 modem dial up supports less than 56 Kbps bandwidth and ISDN handles approximately 128Kbps.
Many home users are currently replacing their dial up services with high-speed broadband technologies that operate at much higher speeds.

Dial up networking technology provides PCs and other network devices access to a LAN or WAN via telephone lines. Dial up Internet service providers offer subscription plans for home computer users.

What is Satellite Internet Access?

Satellite Internet is a form of high-speed Internet service. Satellite Internet services utilize telecommunications satellites in Earth orbit to provide Internet access to consumers.
Satellite Internet service covers areas where DSL and cable access is unavailable. Satellite offers less network bandwidth compared to DSL or cable, however. In addition, the long delays required to transmit data between the satellite and the ground stations tend to create high network latency, causing a sluggish performance experience in some cases. Network applications like VPN and online gaming may not function properly over satellite Internet connections due to these latency issues.
Older residential satellite Internet services supported only "one-way" downloads over the satellite link, requiring a telephone modem for uploading. All newer satellite services support full "two-way" satellite links.
Satellite Internet service does not necessary utilitize WiMax. WiMax technology supplies one method to deliver high-speed Internet service over wireless links, but satellite providers may implement their systems differently

Satellite Internet is a form of high-speed Internet service. Satellite Internet utilizes telecommunications satellites in Earth orbit to provide wireless Internet access to consumers. Satellite Internet covers many areas where DSL and cable services are unavailable.

What is Integrated Services Digital Network:
ISDN is a network technology that supports digital transfer of simultaneous voice and data traffic. Similar to DSL in this respect, an ISDN Internet service works over ordinary telephone lines. ISDN Internet service generally supports data rates of 128 Kbps.
ISDN emerged as an alternative to traditional dialup networking during the 1990s. The relatively high cost of ISDN service, though, limited its popularity with residential customers at the outset. More recently, the much higher network speeds supported by newer broadband technologies like DSL have drawn many consumers away from ISDN service.
ISDN technology today has limited applications as a networking solution. Some customers who live in rural areas of the U.S. subscribe to ISDN Internet as an alternative to satellite Internet. ISDN phone service also remains fairly common in some European countries.

ISDN supports simultaneous voice and data network connectivity over ordinary telephone lines. ISDN emerged as an alternative to traditional dial-up networking during the 1990s, but more recently its popularity has waned.

What is a Default Gateway?
You will sometimes see the term default gateway on network configuration screens in Microsoft Windows.
Answer: In computer networking, a default gateway is the device that passes traffic from the local subnet to devices on other subnets. The default gateway often connects a local network to the Internet, although internal gateways for local networks also exist.

Internet default gateways are typically one of two types:

On home or small business networks with a broadband router to share the Internet connection, the home router serves as the default gateway.
On home or small business networks without a router, such as for residences with dialup Internet access, a router at the Internet Service Provider location serves as the default gateway.
Default network gateways can also be configured using an ordinary computer instead of a router. These gateways use two network adapters, one connected to the local subnet and one to the outside network. Either routers or gateway computers can be used to network local subnets such as those in larger businesses.
In Microsoft Windows, the IP address of a computer's default gateway can be accessed in the 'ipconfig' or 'winipcfg' utilities

In computer networking, a default gateway is the device that passes traffic from the local subnet to devices on other subnets. On home networks, the router serves as the default gateway. (Courtesy by www.about.com)

Networking Security – A Start for Beginner::

An Introduction to the Key Security Issues for the E-Business Economy
With the explosion of the public Internet and e-commerce, private computers, and computer networks, if not adequately secured, are increasingly vulnerable to damaging attacks. Hackers, viruses, vindictive employees and even human error all represent clear and present dangers to networks. And all computer users, from the most casual Internet surfers to large enterprises, could be affected by network security breaches. However, security breaches can often be easily prevented. How? This guide provides you with a general overview of the most common network security threats and the steps you and your organization can take to protect yourselves from threats and ensure that the data traveling across your networks is safe.
Importance of Security
The Internet has undoubtedly become the largest public data network, enabling and facilitating both personal and business communications worldwide. The volume of traffic moving over the Internet, as well as corporate networks, is expanding exponentially every day. More and more communication is taking place via e-mail; mobile workers, telecommuters, and branch offices are using the Internet to remotely connect to their corporate networks; and commercial transactions completed over the Internet, via the World Wide Web, now account for large portions of corporate revenue.