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||UDP (User Datagram Protocol, RFC 768) is a communications protocol, an alternative to TCP (Transmission Control Protocol), and uses the Internet Protocol (IP) to actually get a data units (datagrams) from one network node to another.
UDP does not provide the service of dividing a message into packets (unlike TCP) and reassembling it at the other end. Specifically, UDP doesn't provide sequencing of the packets that the data arrives in.
UDP is a stateless protocol, meaning it doesn't acknowledge that packets being sent have been received. For this reason, the UDP protocol is typically used for streaming media, where a lost packet should not stop the transmission of data, or for simple applications where very little processing power is a requirement. TFTP (Trivial File Transfer Protocol) uses UDP as well.
||UMTS (Universal Mobile Telecommunications System) is a third-generation (3G) broadband, packet-based data transmission technology with data rates up to 2 Mbps. UMTS is based on the GSM communication standard.
||Uncapping refers to the concept of somehow lifting the bandwidth cap many cable modem service providers (MSO's) impose. Some users want to do this in order to improve the speed of their cable modem, obviously circumventing the service provider and may be considered theft of service.
Some early pre-DOCSIS cable modems could be hacked to remove upstream limitations, however, those days are long gone.
Note that speed tweaks (changing TCP Receive Window, etc.) to improve speed are not considered "uncapping" and are absolutely legal way of fixing/tuning your OS to improve network performance.
||Unicode is a 16 bit ISO 10646 character set. It can accommodate way more characters that ASCII, thus allowing for easier internationalization.
||UPnP (Universal Plug and Play) is a standard that defines a connected environment, an automatic network of different, self-configuring devices, such as PCs, peripherals, wireless devices, and intelligent appliances. In a UPnP environment, all those devices would be able to configure themselves, aquire IP address automatically, announce their presense and location on the network (using HTTP), and be able to communicate using Internet and Web protocols.
||upstream (or upload, uplink) is a transmission from the end user to a server and downstream/download is a transmission toward the user. Data rate can differ in the downstream and upstream directions.
||UTM (Unified Threat Management) is a newer type of network security appliance, considered an evolution of the traditional firewall into an all-inclusive security product able to perform multiple security functions within one single device.
UTM is an all-inclusive network gateway that typically includes a firewall, gateway antivirus/anti-malware/anti-spam, web content filtering, IPS (Intrusion Prevention System), VPN, load balancing, and some type of data loss prevention.
||UTP (Unshielded Twisted Pair) is a popular standard cable that consists of pairs of unshielded wires twisted areound each other. UTP cabling is commonly used for Ethernet networks and telephone connections because of its low cost and ease of use.
||VDSL (Very-high-speed Digital Subscriber Line, a.k.a. VADSL, BDSL) is the fastest form of DSL, with the ability to achieve data rates up to approximately 51,840 Kbps for short distances (1000' to 4500'). Currently VDSL is in very limited commercial use.
||VLAN (Virtual LAN) is a network of computers that appear to be connected to the same network even if they are physically located on differend segments of the LAN.
||VoIP (Voice over Internet Protocol) refers to the transmission of voice, such as ordinary telephone calls, over a packet-switched IP network. Also known as IP telephony.
||VPN (Virtual Private Network) is a network of secure links over a public IP infrastructure. Technologies that fit in this category include PPTP (Point-to-Point Tunneling Protocol), L2TP (Layer 2 tunneling protocol) and IPSec.
Note that tunneling and VPN is not intended as a substitute for data encryption by itself. For a higher security level strong encryption should be used within the VPN.
||W3C (World Wide Web Consortium) is an international consortium founded in 1994 that unites over 450 organizations involved with the Internet and the World Wide Web. Its purpose is to
"lead the World Wide Web to its full potential by developing common protocols that promote its evolution and ensure its interoperability". The W3C develops and publishes open standards for the web.
||WAN (Wide Area Network) is a telecommunications network that covers a large area, such as a state or country, spanning multiple LANs. The term often suggests the inclusion of public (shared user) networks.
||WAP (Wireless Application Protocol) is a specification for a set of communication protocols to standardize the way that handheld wireless devices (PDAs, cell phones, pagers, two-way radios) can interoperate and be used for Internet access, including Web, e-mail, Web, newsgroups, IRC, etc.
Also: Wireless Access Point (WAP or AP) - a device, essentially a base station that connects wireless devices together to create a wireless network by transmitting/receiving radio signals. A WAP is usually also connected to a wired network, and can relay data between devices on each side.
||Wardriving is the practice of searching for Wireless LAN (WLAN) signals within a geographic area. It often refers to driving around looking for wireless networks. The term was coined by Pete Shipley. It's a concept taken from the movie "WarGames", where the actor dials many phone numbers looking for computers to access, called "War-Dialing". Other similar terms include war-walking, war-flying, etc. refering to the modes of transportation used for moving around to identify various wireless Access Points.
With many wireless networks being 'plug and play' right out of the box, we are witnessing a tremendous amount of networks that are simply wide open to intrusion. Drive down a city street with just a laptop, a wireless card, and a program such as Netstumbler. You will come across dozens of open networks from which you can access the internet, and potentially the files of the other computers on the network.
||WDM (Wavelength Division Multiplexing) is a type of multiplexing used in optical fiber. WDM modulates each of several data streams onto a different part of the light spectrum.
See also: TDM, FDM.
||WDS (Wireless Distribution System) is a Wireless Access Point mode that enables wireless bridging in which WDS APs communicate only with each other (without allowing for wireless clients or stations to access them), and/or wireless repeating in which APs communicate both with each other and with wireless stations (at the expense of half the throughput).
||WebDAV (Web distributed authoring and versioning) is an industry standard extension to the HTTP specification. WebDAV adds a capability for authorized users to remotely add and manage content on a web server.
For additional information, see RFC 2518.
||WebSocket is a TCP-based communication protocol standardized by [RFC 6455]. It establishes a persistent full-duplex communication channel over a single TCP connection using HTTP handshake, typically over standard TCP port 80.
Unlike traditional HTTP, WebSocket provides full-duplex communication allowing for more interaction between a web browser and a web server. The WebSocket protocol is supported in all modern browsers.
||WEP (Wired Equivalent Privacy) is IEEE security protocol, specified in the Wi-Fi (Wireless Fidelity, or 802.11b) standard. WEP is designed to provide a WLAN (Wireless Local Area Network, a.k.a LAWN ;) ) with a level of security and privacy comparable to what is usually expected of a wired LAN, by encrypting data transmitted over the WLAN.
Although WEP provides some level of security, there has been some controversy whether it lives up to being equivalent to that of wired LANs. Either way, WEP should always be used in conjunction with all other traditional security practices. In 2001, a fast WEP cracking algorithm was discovered, coming from capturing enough "weak IV" frames, something that occurs randomly. Manufactures have since altered the algorithm to not use weak IVs in most devices -- this technology is sometimes known as WEP-plus.
When entering WEP keys manually, note the following guidelines:
- One ASCII character is 8 bits, one Hex character is 4 bits.
- 64 (or 40) bit WEP code has 5 ASCII or 10 HEX characters.
- 128 (or 104) bit WEP code has 13 ASCII or 26 HEX characters.
||Wi-Fi (short for "Wireless Fidelity,") is a term used generically when referring to any type of 802.11 network, such as 802.11b, 802.11g, or 802.11a.
Wi-Fi uses DSSS, and is comparable to Ethernet in functionality. While most Wi-Fi connections are between a mobile device and an access point, it is also possible to create an "ad-hoc" network directly among two or more devices, without an access point.
All Wi-Fi product using the same radio frequency (for example, 2.4GHz for 802.11b & 802.11g, 5GHz for 802.11a) are designed to work with each other. Also, 802.11g products are backward compatible with 802.11b devices, since they use the same 2.4GHz frequency.
Note: Wi-Fi is a trademark of the Wi-Fi Alliance, a nonprofit industry association. The IEEE technical specification for Wi-Fi is 802.11.
||Wi-Fi Direct (a.k.a. Wi-Fi P2P) is a WiFi standard that enables devices to connect with each other easily without the need for a wireless access point. Wi-Fi direct negotiates a peer-to-peer link using WPS, and allows for everything from file transfers to internet connectivity.
||WiGig (802.11ad) is a draft wireless standard that operates on the unlicensed 60GHz spectrum, with theoretical multi-gigabit speeds over a distance of up to 10 meters with no wall propagation. As such, it is not meant as a replacement of WiFi, however, it offers advantages in terms of bandwidth, low power consumption, beamforming, and TDMA, making it a good candidate for mobile devices.
The WiGig MAC specification was published in June 2011, and the standard is currently in draft stage with the IEEE as 802.11ad.
||WiMAX (Worldwide Interoperability for Microwave Access) is a wireless telecommunication technology based on the IEEE 802.16 family of standards, which allows for high-speed wireless data transmission over long distances (5-30 miles).
The initial version, based on 802.16a, is designed for fixed (non-mobile) applications only, such as a wireless replacement for home DSL or cable modem service. Newer versions, such as 802.16e, add support for mobility, potentially making WiMax a competitor for certain 3G or 4G cell-phone technologies.
WiMax operates at higher frequencies than mobile phone networks. WiMax technology can operate in the 2.5 or 3.5 GHz licensed bands, or in the 5.8 GHz unlicensed band.
The name WiMAX was created by the WiMAX Forum, which was formed in June 2001 to promote conformance and interoperability of the standard.
See also: wimaxforum.org
||Windows 9x/ME - "A 32 bit extension and graphical shell, for a 16 bit patch to an 8 bit operating system, originally coded for a 4 bit microprocessor, written by a 2 bit company, that can't stand 1 bit of competition."
Note: Sense of humor required.
||Winsock (the Windows Sockets API) defines how software should access network services, especially TCP/IP. It defines a standard interface between TCP/IP client appliactions (such as an FTP client or a web browser) and the unterlying TCP/IP protocol stack.
Note: Winsock refers to the API, not only the DLL library file (winsock.dll) which only exposes the common WSA interfaces to applications above it.
||WISP (Wireless Internet Service Provider) is an ISP that allows subscribers to connect to a server at designated access points using a wireless connection such as Wi-Fi. This type of ISP offers broadband service and allows subscriber computers, called stations, to access the Internet and the Web from anywhere within the zone of coverage provided by the server antenna(s).
||WLAN (a wireless LAN) is a type of LAN that uses high-frequency radio transmissions (rather than cables) to communicate between network nodes.
Also reffered to as "LAWN" :)
||WLL (Wireless Local Loop) is a term for the use of a wireless communications link as the "last mile" connection for delivering plain old telephone service (POTS) and/or broadband Internet to telecommunications customers. Various types of WLL systems and technologies exist.
||WMM (Wi-Fi Multimedia) is a wireless QoS specification, a subset of 802.11e improving quality of video and voice applications for wireless clients.
It can help control latency and jitter when transmitting multimedia content over a wireless connection.
||WMM (Wi-Fi Multimedia, formerly known as Wireless Multimedia Extensions - WME), is a Wi-Fi Alliance certified feature based on the IEEE 802.11e standard. This feature provides QoS to wireless networks. It is especially suitable for voice, music and video applications; for example, Voice over IP (VoIP), video streaming, and interactive gaming.
||worm is a separate computer program that can replicate itself automatically over a network.
Worms are ofren, but not always, malicious and might interfere with the normal use of a computer or a program. They often exploit vulnerabilities in some automatic file sharing feature found on many computers to replicate.
Worm is different than a virus, it does not alter/infect files and its main ability is to replicate by itself. Still, a malicious worm can be programmed to delete all your files just as well.
||WPA (WiFi Protected Access) is a wireless standard designed to improve upon the security features of WEP. It is designed to work with existing WiFi products (as a software upgrade to existing WEP-capable hardware).
The two improvements over WEP are:
1. Improved data encryption through TKIP (temporal key integrity protocol), which hashes/scrambles the keys and adds an iintegrity-check, ensuring the keys haven't been tampered with.
2. User authentication through EAP (extensible authentication protocol).
WPA takes two forms; WPA Enterprise Mode and WPA Personal, or PSK (Pre-Shared Key) Mode. WPA PSK is somewhat more vulnerable to attacks: a cracker passively intercepting initial key exchange messages can then possibly crack poorly chosen short passphrases with a robust dictionary attack offline and without access to the network.
WPA-Enterprise is an encryption method that protects unauthorized network access by verifying network users through a server.
WPA-Personal is an encryption method that protects unauthorized network access by utilizing a set-up password.
Note: WPA is an interim standard being replaced with the IEEE's now ratified 802.11i standard, branded WPA2.
||WPA2 is the follow up to the Alliance's interim security plan, WPA (Wi-Fi Protected Access). WPA2 is based on the ratified IEEE 802.11i standard, and provides government grade security by implementing the NIST FIPS 140-2 compliant AES encryption algorithm. WPA2 provides network administrators with a high level of assurance that only authorized users can access the network.
WPA2 can be enabled in two versions: WPA2 - Personal and WPA2 - Enterprise. WPA2 - Personal protects unauthorized network access by utilizing a set-up password. WPA2 - Enterprise verifies network users through a server. WPA2 is backward compatible with WPA.
||WPS (Wi-Fi Protected Setup) is a wireless security standard that provides non-technical users with a simple method of securing their wireless network.
The most common implementation includes pushing a physical button on a wireless router/access point. In addition, WPS-certified devices also support an 8-digit PIN, usually printed on a sticker on the device itself for authentication.
Recently (as of December 2011), flaws in WPS have been discovered that affect most major vendors and allow an attacker to crack the WPS PIN within a couple of hours. The U.S. Computer Emergency Readiness Team (US-CERT) has notified vendors and issued an advisory that suggests turning off WPS as an workaround until a better solution is implemented. See vulnerability note VU#723755
||WYSIWYG (What You See Is What You Get, pronounced "wizzy-wig") refers to software that displays what your work will look like while you're creating it.
Sometimes also WYSINQWYG ;) (What You See Is Never Quite What You Get, pronounced "wizzin-quig").
||DSL ( Digital Subscriber Line ) is a method of high-speed data transfer over ordinary copper telephone lines. xDSL refers to the different variations of DSL, such as ADSL, HDSL, SDSL and RADSL.
||XML (Extensible Markup Language) is a flexible way to create common information formats and share both the format and the data, most commonly on the web. It generally similar to HTML and helps share information in a consistent way. XML is "extensible" because, unlike HTML, the markup symbols are unlimited and self-defining.
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