FDDI

This article is about the network traffic analyzer. For more general definitions, see the Wiktionary entry. For the fictional alien race from X-COM: UFO Defense, see Ethereal (alien) In computing, Ethereal (i-'thir-E-&l) is a protocol analyzer, or "packet sniffer" software, used for network troubleshooting, analysis, software and protocol development, and education. It has all o ...

Including:

• Ethereal - Features
• Ethereal - Security

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A computer network is a system for communication between computers. These networks may be fixed (cabled, permanent) or temporary (as via modems or null modems). Carrying instructions between calculation machines and early computers was done by human users. In September, 1940 George Stibitz used a teletype machine to send instructions for a problem set from his Model K at Dartmouth College in New Hampshire to his Complex Number Calculator in New York and received results back by the same means. Linking output systems like telety ...

Including:

• Computer network - Categorizing
• Computer network - By functional relationship
• Computer network - By network topology
• Computer network - By specialized function
• Computer network - Protocol stacks
• Computer network - Suggested topics
• Computer network - Layers
• Computer network - Data transmission
• Computer network - Other

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CRCs are based on division in a commutative ring, namely the ring of polynomials over the integers modulo 2. In simpler terms, this is the set of polynomials where each coefficient is only one bit, and arithmetic operations wrap around. For example: Two becomes zero because addition of coefficients is performed modulo 2. Multiplication is similar: We can also divide polynomials mod 2 and find the quotient and remainder. For example, suppose we're dividing x3 + < ...

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Cyclic redundancy check, Cyclic redundancy check - Introduction, Cyclic redundancy check - Polynomials and types, Cyclic redundancy check - Polynomial CRC key specifications [ITU-IEEE syntax], Cyclic redundancy check - CRCs and data integrity, Cyclic redundancy check - Computational costs of CRCs versus hashes

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The optical fiber can be used as a medium for telecommunication and networking because it is flexible and can be bundled as cables. Although fibers can be made out of either transparent plastic or glass, the fibers used in long-distance telecommunications applications are always glass, because of the lower optical attenuation. Both multi-mode and single-mode fibers are used in communications, with multi-mode fiber used mostly for short distances (up to 500 m), and single-mode fiber used for longer distance links. Because of the tighte ...

See also:

Optical fiber, Optical fiber - Optical description, Optical fiber - Optical fiber communication, Optical fiber - Comparison with electrical transmission, Optical fiber - Governing standards, Optical fiber - Other uses of optical fibers, Optical fiber - Fiber Optic Sensors, Optical fiber - Manufacture, Optical fiber - Optical fiber cables, Optical fiber - History, Optical fiber - Footnotes

Read more here: » Optical fiber: Encyclopedia II - Optical fiber - Optical fiber communication

OSI model - Layer 1: Physical layer. The Physical layer defines all the electrical and physical specifications for devices. This includes the layout of pins, voltages, and cable specifications. Hubs, repeaters and network adapters are physical-layer devices. The major functions and services performed by the physical layer are: establishment and termination of a connection to a communications medium. participation in the process whereby the communication resources are effectively shared among ...

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OSI model, OSI model - Purpose, OSI model - Description of OSI layers, OSI model - Layer 1: Physical layer, OSI model - Layer 2: Data Link layer, OSI model - Layer 2.5, OSI model - Layer 3: Network layer, OSI model - Layer 4: Transport layer, OSI model - Layer 5: Session layer, OSI model - Layer 6: Presentation layer, OSI model - Layer 7: Application layer, OSI model - Interfaces, OSI model - Table of examples, OSI model - Parallel, OSI model - Humor

Read more here: » OSI model: Encyclopedia II - OSI model - Description of OSI layers

Most models have basic layer 2 functions and are capable of switching Ethernet frames between ports. Commonly found additional features are VLANs, trunking (Cisco proprietary ISL or IEEE 802.1Q) and QoS or CoS. The switches, whether IOS or CatOS, are fully manageable. Any Catalyst that runs IOS is also capable of functioning as a Router, making them layer 3 devices -- couple this with TCP and UDP filtering, and IOS-enabled switches are capable of layer 2-4 operation. Depending on the exact software image, a Catalyst that runs IOS may be able to tackle large-scale enterprise routing tasks, ...

See also:

Catalyst switch, Catalyst switch - Operating Systems, Catalyst switch - Interfaces, Catalyst switch - Features, Catalyst switch - Models

Read more here: » Catalyst switch: Encyclopedia II - Catalyst switch - Features

OSI model - Layer 1: Physical layer. The Physical layer defines all the electrical and physical specifications for devices. This includes the layout of pins, voltages, and cable specifications. Hubs, repeaters and network adapters are physical-layer devices. The major functions and services performed by the physical layer are: establishment and termination of a connection to a communications medium. participation in the process whereby the communication resources are effectively shared among ...

See also:

OSI model, OSI model - Purpose, OSI model - Description of layers, OSI model - Layer 1: Physical layer, OSI model - Layer 2: Data Link layer, OSI model - Layer 2.5, OSI model - Layer 3: Network layer, OSI model - Layer 4: Transport layer, OSI model - Layer 5: Session layer, OSI model - Layer 6: Presentation layer, OSI model - Layer 7: Application layer, OSI model - Interfaces, OSI model - Table of examples, OSI model - Parallel, OSI model - Humor

Read more here: » OSI model: Encyclopedia II - OSI model - Description of layers

As promiscuous mode can be used in a malicious way to sniff on a network, one might be interested in detecting network devices that are in promiscuous mode. There are basically two methods to do this: If a network device is in promiscuous mode, the kernel will receive all network traffic, i. e. the CPU load will increase. Then the latency of network responses will also increase, which can be detected. Of course, this method is very unreliable as the CPU load could just be higher for another reason. In promiscuous ...

See also:

Promiscuous mode, Promiscuous mode - Detection

Read more here: » Promiscuous mode: Encyclopedia II - Promiscuous mode - Detection

Stations on a Token-Ring LAN are logically organized in a ring topology with data being transmitted sequentially from one ring station to the next with a control token circulating around the ring controlling access. This token passing mechanism is shared by ARCNET, Token Bus, and FDDI, and has theoretical advantages over the stochastic CSMA/CD of Ethernet. Physically, a Token-Ring network is wired as a star, with 'hubs' and arms out to each station and the loop going out-and-back through each. Cabling is generally IBM "Type-1" Shielded Twisted Pair, ...

See also:

Token ring, Token ring - Overview, Token ring - Token frame, Token ring - Token ring frame format, Token ring - Active and standby monitors, Token ring - Token ring insertion process

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Other than the framing types mentioned above, most of the other differences between Ethernet varieties have all been variations on speed and wiring. Therefore, in general, network protocol stack software will work identically on most of the following types. The following sections provide a brief summary of all the official Ethernet media types. In addition to these official standards, many vendors have implemented proprietary media types for various reasons—often to ...

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Ethernet, Ethernet - History, Ethernet - General description, Ethernet - CSMA/CD shared medium Ethernet, Ethernet - Ethernet repeaters and hubs, Ethernet - Bridging and Switching, Ethernet - Dual speed hubs, Ethernet - Ethernet frame types and the EtherType field, Ethernet - Varieties of Ethernet, Ethernet - Some early varieties of Ethernet, Ethernet - 10 Mbit/s Ethernet, Ethernet - Fast Ethernet 100 Mbit/s, Ethernet - Gigabit Ethernet, Ethernet - 10 Gigabit Ethernet, Ethernet - Related standards, Ethernet - Implementations

Read more here: » Ethernet: Encyclopedia II - Ethernet - Varieties of Ethernet

Computer network - By functional relationship. Client-server Peer-to-peer (Workgroup) Computer network - By network topology. Bus network Star network Ring network Mesh network Star-bus network Computer network - By specialized function. Storage area networks Server farms Process control networks Value added network SOHO net ...

See also:

Computer network, Computer network - Categorizing, Computer network - By functional relationship, Computer network - By network topology, Computer network - By specialized function, Computer network - Protocol stacks, Computer network - Suggested topics, Computer network - Layers, Computer network - Data transmission, Computer network - Other

Read more here: » Computer network: Encyclopedia II - Computer network - Categorizing

Please add your own entries, in this page or in the appropriate sub-page. Use a quasi-dictionary order, with lowercase treated the same as uppercase and ignoring non-alphanumeric characters (hyphens and such). This means that only alphanumeric characters have any significance in determining order, and that lowercase letters occupy the same ordering position as uppercase (in tie-breaker cases, list lower case first). For example: Ka appears before KA. (This differs from a strict ASCII ordering) (Main list of acronyms an ...

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List of acronyms and initialisms: F, List of acronyms and initialisms: F - Add new entries here or in the sub-pages, List of acronyms and initialisms: F - FA, List of acronyms and initialisms: F - FB, List of acronyms and initialisms: F - FC, List of acronyms and initialisms: F - FD, List of acronyms and initialisms: F - FE, List of acronyms and initialisms: F - FF, List of acronyms and initialisms: F - FG, List of acronyms and initialisms: F - FH, List of acronyms and initialisms: F - FI, List of acronyms and initialisms: F - FJ, List of acronyms and initialisms: F - FK, List of acronyms and initialisms: F - FL, List of acronyms and initialisms: F - FM, List of acronyms and initialisms: F - FN, List of acronyms and initialisms: F - FO, List of acronyms and initialisms: F - FP, List of acronyms and initialisms: F - FQ, List of acronyms and initialisms: F - FR, List of acronyms and initialisms: F - FS, List of acronyms and initialisms: F - FT, List of acronyms and initialisms: F - FU, List of acronyms and initialisms: F - FV, List of acronyms and initialisms: F - FW, List of acronyms and initialisms: F - FX, List of acronyms and initialisms: F - FY, List of acronyms and initialisms: F - FZ

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The optical fiber can be used as a medium for telecommunication and networking because it is flexible and can be bundled as cables. Although fibers can be made out of either transparent plastic or glass, the fibers used in long-distance telecommunications applications are always glass, because of the lower optical attenuation. Both multi-mode and single-mode fibers are used in communications, with multi-mode fiber used mostly for short distances (up to 500 m), and single-mode fiber used for longer distance links. Because of the tighte ...

See also:

Optical fiber, Optical fiber - Optical description, Optical fiber - Materials, Optical fiber - Optical fiber communication, Optical fiber - Comparison with electrical transmission, Optical fiber - Governing standards, Optical fiber - Other uses of optical fibers, Optical fiber - Fiber Optic Sensors, Optical fiber - Manufacture, Optical fiber - Optical fiber cables, Optical fiber - History, Optical fiber - Footnotes

Read more here: » Optical fiber: Encyclopedia II - Optical fiber - Optical fiber communication

The original IEEE 802 MAC address, now officially called "MAC-48", comes from the Ethernet specification. Since the original designers of Ethernet had the foresight to use a 48-bit address space, there are potentially 248 or 281,474,976,710,656 possible MAC addresses. All three numbering systems use the same format, and differ only in the length of the identifier. The first three octets (in transmission order) identify the organization which issued the identifier, and are known as the Organizationally Unique Identifier (OUI ...

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MAC address, MAC address - Address details, MAC address - Printed format, MAC address - Changing MAC addresses, MAC address - Linux, MAC address - FreeBSD, MAC address - OpenBSD, MAC address - Mac OS X, MAC address - Windows, MAC address - Other systems, MAC address - Change The MAC Address Permanently

Read more here: » MAC address: Encyclopedia II - MAC address - Address details

Ring network - Advantages. All stations have equal access Each node on the ring acts as a repeater, allowing ring networks to span greater distances than other physical topologies. Because data travels in one direction high speeds of transmission of data are possible When using a coaxial cable to create a ring network the service becomes much faster. Ring network - Disadvantages. Often the most expensive topology Numerous c ...

See also:

Ring network, Ring network - Advantages and Disadvantages of a Ring Network, Ring network - Advantages, Ring network - Disadvantages

Read more here: » Ring network: Encyclopedia II - Ring network - Advantages and Disadvantages of a Ring Network

The physical interconnections used for Peering are categorized into two types: Public peering - Interconnection through a Shared fabric such as an Ethernet, ATM, or FDDI switch. Private peering - Interconnection through a Direct or Dedicated circuit, either Telco or Dark. Peering - Public Peering. Public peering is accomplished across a Layer 2 access technology, generally called a Shared fabric. At these locations, multiple carriers interconnect wit ...

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Peering, Peering - How peering works, Peering - Motivations for Peering, Peering - Physical Interconnections for Peering, Peering - Public Peering, Peering - Private Peering, Peering - Peering Agreements/Contracts, Peering - History of Peering, Peering - Depeering, Peering - Modern Peering, Peering - Peering Locations, Peering - Exchange Points and Colocation Facilities, Peering - Peering and BGP, Peering - Peering Dos and Don'ts

Read more here: » Peering: Encyclopedia II - Peering - Physical Interconnections for Peering

Optical fibers can be used as sensors to measure strain, temperature, pressure and other parameters. The small size and the fact that no electrical power is needed at the remote location gives the fiber optic sensor advantages to conventional electrical sensor in certain applications. Optical fibers are used as hydrophones for seismic or SONAR applications. Hydrophone systems with more than 100 sensors per fiber cable have been developed. Hydrophone sensor systems are used by the oil industry as well as a few countries' navies. Both b ...

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Optical fiber, Optical fiber - Optical description, Optical fiber - Materials, Optical fiber - Optical fiber communication, Optical fiber - Comparison with electrical transmission, Optical fiber - Governing standards, Optical fiber - Other uses of optical fibers, Optical fiber - Fiber Optic Sensors, Optical fiber - Manufacture, Optical fiber - Optical fiber cables, Optical fiber - History, Optical fiber - Footnotes

Read more here: » Optical fiber: Encyclopedia II - Optical fiber - Fiber Optic Sensors

Optical fiber is made by first constructing a large-diameter preform, with a carefully controlled refractive index profile, and then pulling the preform to form the long, thin optical fiber. The preform is commonly made by three chemical vapor deposition methods: inside vapor deposition, outside vapor deposition, and vapor axial deposition. In inside vapor deposition, a hollow glass tube approximately 40 cm in length known as a "preform" is placed horizontally and rotated slowly on a lathe, and gases ...

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Optical fiber, Optical fiber - Optical description, Optical fiber - Materials, Optical fiber - Optical fiber communication, Optical fiber - Comparison with electrical transmission, Optical fiber - Governing standards, Optical fiber - Other uses of optical fibers, Optical fiber - Fiber Optic Sensors, Optical fiber - Manufacture, Optical fiber - Optical fiber cables, Optical fiber - History, Optical fiber - Footnotes

Read more here: » Optical fiber: Encyclopedia II - Optical fiber - Manufacture

In practical fibers, the cladding is usually coated with a tough resin buffer layer, which may be further surrounded by a jacket layer, usually plastic. These layers add strength to the fiber but do not contribute to its optical wave guide properties. For indoor applications, the jacketed fiber is generally enclosed, with a bundle of flexible fibrous polymer (e.g. Kevlar) strength members, in a lightweight plastic cover to form a simple cable. Each end of the cable may be terminated with a specialized optical fiber connector to allow it to be easily connected and d ...

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Optical fiber, Optical fiber - Optical description, Optical fiber - Materials, Optical fiber - Optical fiber communication, Optical fiber - Comparison with electrical transmission, Optical fiber - Governing standards, Optical fiber - Other uses of optical fibers, Optical fiber - Fiber Optic Sensors, Optical fiber - Manufacture, Optical fiber - Optical fiber cables, Optical fiber - History, Optical fiber - Footnotes

Read more here: » Optical fiber: Encyclopedia II - Optical fiber - Optical fiber cables

The history of dielectric optical lightguides goes back to Victorian times, when the total internal reflection principle was used to illuminate streams of water in elaborate public fountains. Later development, in the early-to-mid twentieth century, focused on the development of fiber bundles for image transmission, with the primary application being the medical gastroscope. The first fiber optic semi-flexible gastroscope was patented by Basil Hirschowitz, C. Wilbur Peters, and Lawrence E. Curtiss in 1956. In the process of developing the ga ...

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Optical fiber, Optical fiber - Optical description, Optical fiber - Materials, Optical fiber - Optical fiber communication, Optical fiber - Comparison with electrical transmission, Optical fiber - Governing standards, Optical fiber - Other uses of optical fibers, Optical fiber - Fiber Optic Sensors, Optical fiber - Manufacture, Optical fiber - Optical fiber cables, Optical fiber - History, Optical fiber - Footnotes

Read more here: » Optical fiber: Encyclopedia II - Optical fiber - History