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Network Tap
A network tap is a system that monitors events on a local network. A tap is typically a dedicated hardware device, which provides a way to access the data flowing across a computer network. The network tap has (at least) three ports: an ''A port'', a ''B port'', and a ''monitor'' port. A tap inserted between A and B passes all traffic (send and receive data streams) through unimpeded in real time, but also copies that same data to its monitor port, enabling a third party to listen. Network taps are commonly used for network intrusion detection systems, VoIP recording, network probes, RMON probes, packet sniffers, and other monitoring and collection devices and software that require access to a network segment. Taps are used in security applications because they are non-obtrusive, are not detectable on the network (having no physical or logical address), can deal with full-duplex and non-shared networks, and will usually ''pass through'' or ''bypass'' traffic even if the tap stops ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Network
A computer network is a collection of communicating computers and other devices, such as printers and smart phones. In order to communicate, the computers and devices must be connected by wired media like copper cables, optical fibers, or by wireless communication. The devices may be connected in a variety of network topologies. In order to communicate over the network, computers use agreed-on rules, called communication protocols, over whatever medium is used. The computer network can include personal computers, Server (computing), servers, networking hardware, or other specialized or general-purpose Host (network), hosts. They are identified by network addresses and may have hostnames. Hostnames serve as memorable labels for the nodes and are rarely changed after initial assignment. Network addresses serve for locating and identifying the nodes by communication protocols such as the Internet Protocol. Computer networks may be classified by many criteria, including the tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Network Switch
A network switch (also called switching hub, bridging hub, Ethernet switch, and, by the IEEE, MAC bridge) is networking hardware that connects devices on a computer network by using packet switching to receive and forward data to the destination device. A network switch is a multiport network bridge that uses MAC addresses to forward data at the data link layer (layer 2) of the OSI model. Some switches can also forward data at the network layer (layer 3) by additionally incorporating routing functionality. Such switches are commonly known as layer-3 switches or multilayer switches. Switches for Ethernet are the most common form of network switch. The first MAC Bridge was invented in 1983 by Mark Kempf, an engineer in the Networking Advanced Development group of Digital Equipment Corporation. The first 2 port Bridge product (LANBridge 100) was introduced by that company shortly after. The company subsequently produced multi-port switches for both Ethernet and FDDI such as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
In-band
In telecommunications, in-band signaling is the sending of control information within the same band or channel used for data such as voice or video. This is in contrast to out-of-band signaling which is sent over a different channel, or even over a separate network. In-band signals may often be heard by telephony participants, while out-of-band signals are inaccessible to the user. The term is also used more generally, for example of computer data files that include both literal data, and metadata and/or instructions for how to process the literal data. Telephony When dialing from a land-line telephone, the telephone number is encoded and transmitted across the telephone line in form of dual-tone multi-frequency signaling (DTMF). The tones control the telephone system by instructing the telephone switch where to route the call. These control tones are sent over the same channel, the copper wire, and in the frequency range (300 Hz to 3.4 kHz) as the audio of the tele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Network Monitoring
Network monitoring is the use of a system that constantly monitors a computer network for slow or failing components and that notifies the network administrator (via email, SMS or other alarms) in case of outages or other trouble. Network monitoring is part of network management. Details While an intrusion detection system monitors a network threats from the outside, a network monitoring system monitors the network for problems caused by overloaded or crashed servers, network connections or other devices. For example, to determine the status of a web server, monitoring software may periodically send an HTTP request to fetch a page. For email servers, a test message might be sent through SMTP and retrieved by IMAP or POP3. Commonly measured metrics are response time, availability and uptime, although both consistency and reliability metrics are starting to gain popularity. The widespread addition of WAN optimization devices is having an adverse effect on most network monitorin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Link Aggregation
In computer networking, link aggregation is the combining ( aggregating) of multiple network connections in parallel by any of several methods. Link aggregation increases total throughput beyond what a single connection could sustain, and provides redundancy where all but one of the physical links may fail without losing connectivity. A link aggregation group (LAG) is the combined collection of physical ports. Other umbrella terms used to describe the concept include trunking, bundling, bonding, channeling or teaming. Implementation may follow vendor-independent standards such as Link Aggregation Control Protocol (LACP) for Ethernet, defined in IEEE 802.1AX or the previous IEEE 802.3ad, but also proprietary protocols. Motivation Link aggregation increases the bandwidth and resilience of Ethernet connections. Bandwidth requirements do not scale linearly. Ethernet bandwidths historically have increased tenfold each generation: , , , . If one started to bump into bandwidth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Channel Bonding
In computer networking, link aggregation is the combining (wikt:aggregation, aggregating) of multiple network connections in parallel by any of several methods. Link aggregation increases total throughput beyond what a single connection could sustain, and provides redundancy (engineering), redundancy where all but one of the physical links may fail without losing connectivity. A link aggregation group (LAG) is the combined collection of physical ports. Other umbrella terms used to describe the concept include trunking, bundling, bonding, channeling or teaming. Implementation may follow vendor-independent standards such as Link Aggregation Control Protocol (LACP) for Ethernet, defined in #802.1AX, IEEE 802.1AX or the previous #802.3ad, IEEE 802.3ad, but also proprietary protocols. Motivation Link aggregation increases the bandwidth and resilience of Ethernet connections. Bandwidth requirements do not scale linearly. Ethernet bandwidths historically have increased tenfold each ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Throughput
Network throughput (or just throughput, when in context) refers to the rate of message delivery over a communication channel in a communication network, such as Ethernet or packet radio. The data that these messages contain may be delivered over physical or logical links, or through network nodes. Throughput is usually measured in bits per second (, sometimes abbreviated bps), and sometimes in packets per second ( or pps) or data packets per time slot. The system throughput or aggregate throughput is the sum of the data rates that are delivered over all channels in a network. Throughput represents digital bandwidth consumption. The throughput of a communication system may be affected by various factors, including the limitations of the underlying physical medium, available processing power of the system components, end-user behavior, etc. When taking various protocol overheads into account, the useful rate of the data transfer can be significantly lower than the maximum a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Live CD
A live CD (also live DVD, live disc, or live operating system) is a complete booting, bootable computer installation including operating system which runs directly from a CD-ROM or similar storage device into a computer's memory, rather than loading from a hard disk drive. A live CD allows users to run an computer operating system, operating system for any purpose without installing it or making any changes to the computer's configuration. Live CDs can run on a computer without Computer data storage, secondary storage, such as a hard disk drive, or with a corrupted hard disk drive or file system, allowing data recovery. As CD and DVD drives have been steadily phased-out, live CDs have become less popular, being replaced by live USBs, which are equivalent systems written onto USB flash drives, which have the added benefit of having writeable storage. The functionality of a live CD is also available with an Disk enclosure, external hard disk drive connected by USB. Many live CDs o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fiber Tapping
Fiber tapping uses a network tap method that extracts signal from an optical fiber without breaking the connection. Tapping of optical fiber allows diverting some of the signal being transmitted in the core of the fiber into another fiber or a detector. Fiber to the home (FTTH) systems use beam splitters to allow many users to share one backbone fiber connecting to a central office, cutting the cost of each connection to the home. Test equipment can simply put a bend in the fiber and extract sufficient light to identify a fiber or determine if a signal is present. Similar techniques can surreptitiously tap fiber for surveillance, although this is rarely done where electronic equipment used in telecommunication is required to allow access to any phone line for tapping by legal authorization. Tapping the fiber means that all signals from every communications source being routed through the fiber are presented and must be sorted for relevant data, an immense task when thousa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fiber Optic Tap
A fiber-optic splitter, also known as a beam splitter, is based on a quartz substrate of an integrated waveguide optical power distribution device, similar to a coaxial cable transmission system. The optical network system uses an optical signal coupled to the branch distribution. The fiber optic splitter is one of the most important passive devices in the optical fiber link. It is an optical fiber tandem device with many input and output terminals, especially applicable to a passive optical network ( EPON, GPON, BPON, FTTX, FTTH etc.) to connect the main distribution frame and the terminal equipment and to branch the optical signal. Types According to the principle, fiber optic splitters can be divided into Fused Biconical Taper (FBT) splitter and Planar Lightwave Circuit (PLC) splitters. The FBT splitter is one of the most common. FBT splitters are widely accepted and used in passive networks, especially for instances where the split configuration is smaller (1×2, 1×4, 2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Token Ring
Token Ring is a Physical layer, physical and data link layer computer networking technology used to build local area networks. It was introduced by IBM in 1984, and standardized in 1989 as IEEE Standards Association, IEEE 802.5. It uses a special three-byte frame (networking), frame called a ''token'' that is passed around a logical ''ring'' of workstations or server (computing), servers. This token passing is a channel access method providing fair access for all stations, and eliminating the collision (telecommunications), collisions of contention (telecommunications), contention-based access methods. Following its introduction, Token Ring technology became widely adopted, particularly in corporate environments, but was gradually eclipsed by newer iterations of Ethernet. The last formalized Token Ring standard that was completed was Gigabit Token Ring (IEEE 802.5z), published on May 4, 2001. History A wide range of different local area network technologies were developed in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FDDI
Fiber Distributed Data Interface (FDDI) is a standard for data transmission in a local area network. It uses optical fiber as its standard underlying physical medium. It was also later specified to use copper cable, in which case it may be called CDDI (Copper Distributed Data Interface), standardized as TP-PMD (Twisted-Pair Physical Medium-Dependent), also referred to as TP-DDI (Twisted-Pair Distributed Data Interface). FDDI was effectively made obsolete in local networks by Fast Ethernet which offered the same 100 Mbit/s speeds, but at a much lower cost and, from 1998 on, by Gigabit Ethernet due to its speed, even lower cost, and ubiquity. Description FDDI provides a 100 Mbit/s optical standard for data transmission in local area network that can extend in length up to . Although FDDI logical topology is a ring-based token network, it did not use the IEEE 802.5 Token Ring Communications protocol, protocol as its basis; instead, its protocol was derived from the IE ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
