Networking Wordlist (hardware and software)

10BASE-2 (Thin net)
An 802.3 standard for LAN. 10 megabit/second over distances up to 185 meters (607 ft.) on thin coaxial cable. The specifications allow 30 or fewer MAUs per cable segment spaced at no less than 0.5 meter (1.64 ft.). Both ends of the segment must be terminated with a 50 ohm terminator. Earth grounding of the segment shield must take place at only one point on the cable.
10BASE-5 (Thick net)
An 802.3 standard for LAN. 10 megabit/second over distances up to 500 meters (1640 ft.) on thick coaxial cable. The specifications allow 100 or fewer MAU attachments, spaced at multiples of 2.5 meters (8.2 ft.) measured accurately from the cable end (50 ohm terminator included).
10BASE-FL (Fiber link)
An 802.3 standard for LAN. 10 megabit/second over distances up to 2000 meters (6560 ft.) on multimode duplex fiber optic cable (duplex refers to cable pairs) in a point-to-point link which directly attaches two MAUs.
10BASE-T (Twisted pair)
An 802.3 standard for LAN. 10 megabit/second over distances up to 100 meters (328 ft.) Cat 3 cable (or better) should be used. The most common connector used is RJ-45. Se The Ethernet 10Base-T Straight Thru patch cord.
100BASE-Tx (Fast Ethernet)
An 802.3u/D2 standard for 100 megabit/second. Packets are identical to 802.3 packets (with bit-times 1/10 the time), but the nature of CSMA/CD requires that the overall radius of the net be limited to 1/10 the size of 10Mbps Ethernet. Single-hub networks allow up to 325 meters (e.g. 225 meters of fiber for one link and 100 meters of twisted pair for any other link). Extension of the net beyond this would require a switch or router. It also requires users to install new network adapter cards, hubs and switches if they are not prepared for 100BASE-Tx.
100VG-AnyLAN (Voice Grade at any LAN)
An 802.12 standard for 100 megabit/second. This standard eliminates packets collisions and permits more efficient use of network bandwidth. It does this by using the DPA scheme instead of the CSMA/CD scheme used in 10BASE-T and 100BASE-Tx. It also requires users to install new network adapter cards, hubs and switches. Although the name AnyLAN is given because it can transfer either Ethernet and Token Ring frames, both may not be used on the same segment; they must be physically segregated on separate segments by a device such as a router.
1000BASE-CX (Gigabit Ethernet)
An IEEE 802.3z standard for 1 Gigabit/second up to 25 meter. 1000BASE-CX is a standard intended for use in a switching closet or computer room as a short jumper. Uses a special balanced 150-ohm cable, called twinax cable.
1000BASE-LX (Gigabit Ethernet Long-wavelength)
An IEEE 802.3z standard for 1 Gigabit/second up to 3000 meter. Uses Singlemode Fiber and requires SC connectors for terminating the fiber-optic cable.
1000BASE-SX (Gigabit Ethernet Short-wavelength)
An IEEE 802.3z standard for 1 Gigabit/second. Uses Multimode Fiber 50µm core (max 300 m) or 62,5 µm core (max 500 m) and requires SC connectors for terminating the fiber-optic cable.
1000BASE-T (Gigabit Ethernet)
An IEEE 802.3ab standard for 1 Gigabit/second up to 100 meter (Final approval is targeted for March, 1999). Cat 5 is planned to be the required cable standard.
ARP (Address Resolution Protocol)
The Internet and TCP/IP protocol used to dynamically bind a high-level IP address, such as an Internet address, to a low-level physical hardware address. ARP operates only across a single physical network.
AUI (Attachment Unit Interface)
Also known as DIX (DEC® -Intel® - Xerox®). The interface between a MAU and a node.
AUI cable
The AUI cable is used to connect an external transceiver to a device (computer). It has one D-type DCE connector in one end, and a D-type DTE in the other.
AUI Cable Pin outs (15-pin Ethernet connector)
The DTE end:
PIN Number Signal name Signal Direction Electrical characteristics Signal definition
1 CI-S N/A GROUND SHIELD FOR CI-A AND CI-B
2 CI-A INPUT 10 MHz FUNDAMENTAL SQUARE WAVE (+/-700mV) COLLISION IN CIRCUIT A
3 DO-A OUTPUT N/A 10 MBaud DATA OUT CIRCUIT A (MANCHESTER ENCODED)
4 DI-S N/A SIGNAL GROUND SHIELD FOR DI-A AND DI-B
5 DI-A INPUT N/A 10 MBaud DATA IN CIRCUIT A (MANCHESTER ENCODED)
6 VC N/A GROUND VOLTAGE COMMON (POWER FOR MAU)
7 NO CONNECT N/A N/A N/A
8 NO CONNECT N/A N/A N/A
9 CI-B INPUT 10 MHz FUNDAMENTAL SQUARE WAVE (+/-700mV) COLLISION IN CIRCUIT B
10 DO-B OUTPUT N/A 10 MBaud DATA OUT CIRCUIT B (MANCHESTER ENCODED)
11 DO-S N/A SIGNAL GROUND SHIELD FOR DO-A AND DO-B
12 DI-B INPUT N/A 10 MBaud DATA IN CIRCUIT B (MANCHESTER ENCODED)
13 VP N/A POWER (500 mA MAX, +12V TO +15V NOM.) VOLTAGE PLUS (POWER FOR MAU)
14 VS N/A GROUND SHIELD FOR VC AND VP
15 NO CONNECT N/A N/A N/A
Auto Partition
A feature of 10BASE-T. When 32 consecutive collisions are sensed by a port in a hub or concentrator from its attached workstation or network segment, or when a packet that exceeds the maximum allowable length by far is received, the port stops forwarding packets. The port continues to monitor traffic and will automatically begin normal packet forwarding when the first correct packet is received.
AWG (American Wire Gauge)
A standard for determining wire size. The gauge varies inversely with the actual wire diameter.
Backbone
A segment of a network that's often a higher speed than the rest of the network and connects all the other segments. If you don't have a fast backbone, it will be a bottleneck and the network will lag.
BNC connector (Bayonet Neill-Concelman)
Also referred to as a Barrel Nut Connector. The most common connector for 10BASE-2.
Broadcast
One to all sending of packets on a LAN. Ethernets use MAC address FF:FF:FF:FF:FF:FF for broadcast transmissions. Only apply to UDP and not to TCP.
Carrier Sense (CS)
The monitoring of a LAN by a node to determine if another node is transmitting.
Category system (cat 1, 2, 3, 4 and 5)
An EIA/TIA LAN cable specification. See the LEVEL system.
CAT Rated to Specs. etc.
1 - CCITT. No performance criteria
2 1 MHz RS232. Used for telephone wiring
3 16 MHz 10BASE-T, ISDN
4 20 MHz 10BASE-T, Token- Ring
5 100 MHz 10BASE-T, 100Base-TX
CHAP (Challenge Handshake Authentication Protocol)
Like PAP, it is based on the client and server having a shared secret, but the secret is never passed in clear text over the link. Instead, the server sends a challenge - an arbitrary string of bytes, and the client must prove it knows the shared secret by generating a hash value from the challenge combined with the shared secret, and sending the hash value back to the server. The server also generates the hash value and compares it with the value received from the client. Microsoft has its own variant, MS-CHAP, which uses a different hashing arrangement from normal CHAP.
Collision Detect (CD)
A collision occurs when two nodes (or more) attempt to transmit on the network at the same time. When it occurs, both nodes recognize the collision, stop transmission, wait for a random time interval, and then attempt to retransmit. See ethernet jam.
Coax (Coaxial cable)
A two conductor (center conductor, shield system), concentric, constant impedance transmission line used as the trunc medium in the baseband system.
Crossover Cable
If you want to connect two hubs or directly connect two RJ45 Ethernet network devices, use a crossover cable. It is like a null modem, connecting one device's transmit to the other device's receive. Make a Straight Thru patch cord but change one side like this: 
Pin -> Pin
 1  ->  3
 2  ->  6
 3  ->  1
 6  ->  2
Crosstalk
Unwanted interference from another adjacent communications channel. The signal from the adjacent channel is inserted into the original communications channel.
CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance)
An IEEE 802.11 standard for wireless Ethernet. This is a modified version of CSMA/CD. The receiver allways have to acknowledge every package it receives. If the transmitter doesn't receive an acknowledge it assumes a collision and it resend the package.
CSMA/CD (Carrier Sense Multiple Access with Collision Detect)
This is the access method employed by IEEE 802.3 LAN transceivers, by which multiple stations compete for the use of the transmission medium for data packet transmission, and provides for a level of error detection. See Ethernet.
CT switching (cut-through)
Cut-through switching means sending the packet on before it is completely received and implies very low-latency which is good for network services that alternate packets in each direction, but it transmits runts and erroneous packets. See SAF switching.
DIN 4 (D4)
Single fiber optic connector for use in fiber networks. Not common.
Datagram
A self-contained, independent entity of data carrying sufficient information to be routed from the source to the destination computer without reliance on earlier exchanges between this source and destination computer and the transporting network.
DCE (Data Communications Equipment)
Communications equipment installed in a user's premises responsible for establishing, maintaining and terminating a connection. A modem is an example.
DPA method (Demand Priority Access)
In the 802.12 (100VG-AnyLAN) standard, a new method of resolving hub-based LAN contention. Workstations can request either a high or low priority service from the hub. The two priority levels permit priority transfer of delay-sensitive traffic and thus the support of voice, video or multimedia applications (compare with CSMA/CD).
DTE (Data Terminal Equipment)
A piece of equipment where a communications path ends. The user's equipment is collectively termed DTE and can include PCs and display terminals.
DHCP (Dynamic Host Control Protocol)
A protocol for assigning host parameters from a central source. Replaces the older BOOTP protocol. This simplifies the management of large networks and can make changes much easier to implement. Typically at boot time a client will do a broadcast request and the DHCP server on that network segment will provide it with all neccessary parameters. For example this can be IP number, default gateway, DNS, and more, depending on implementation.
DMZ (De-Militarised Zone)
From the military term for an area between two opponents where fighting is prevented.
It is used to refer to any kind of screened subnet placed between the internal networks and the Internet (or other external networks). The borders are usually protected by firewalls.
DNS (Domain Name System)
A way to map domain names to IP numbers and back. It can best be descibed as a distributed database, where each DNS server manages it's own portion of it. The glue making this work is it's hierarchical design and the use of a few specialized root servers.
EIA/TIA (Electronic Industry Association/Telecommunications Industry Association)
Ethernet
A LAN standard defining a physical medium and its method of placing data, or packet signaling, on a cable. Based on CSMA/CD.
Face Contact (FC)
Single fiber optic connector for use in fiber networks. Uses a anti-rotation key to prevent fiber endface damage. Originally designed by Nippon Telephone & Telegraph.
Fiber Size
When 2 numbers are specified the first number refers to the core diameter and the second number refers to the cladding diameter (it's a reflective coating material on the core). If there is a third number it specifies the buffer size (it's a coating applied directly on the cladding for strength and protection). All values are in microns. The most common size for multimode fiber is 62.5/125 and 9/125 for singlemode fiber.
Hub (multiport repeater)
A hub is a central signal distributor. It is used in a wiring topology consisting of several point-to-point segments originating from a central point (also known as star topology). The interface type that IEEE specifies as standard for 10BASE-T repeaters (hubs) is MDI-X. Multiport 10BASE-2, 10BASE-FL, 10BASE-T, 100Base-TX and 100VG-AnyLAN repeaters are considered hubs. See Switch.
HTTP (HyperText Transfer Protocol)
 
IEEE (Institute of Electrical and Electronic Engineers)
 
IEEE 802.1
The IEEE 802 standard for Network Management and Network Bridging of IEEE 802 networks.
IEEE 802.2
An IEEE standard for the portion of LAN data-link protocols that is the same for all IEEE LAN protocols.
IEEE 802.3
An IEEE standard for Ethernet LANs based on CSMA/CD. Standards for interface and protocol specifications for Ethernet in accordance with the OSI model.

The following chart shows the characteristics of the major standards:

802.3 Standard Operating rate Max Segment Length MAUs/segment Medium Topology
10BASE-2 10 Mbps 185 m (607 ft) 30 Coax Bus
10BASE-5 10 Mbps 500 m (1640 ft) 100 Coax Bus
10BASE-FL 10 Mbps 2000 m (6560 ft) 2 Fiber Optic Star
10BASE-T 10 Mbps 100 m (328 ft) 2 UTP cat 3 Star
100BASE-Tx 100 Mbps 100 m (328 ft)* 2 UTP cat 5 Star

* See 100BASE-Tx.

IEEE 802.4
An IEEE standard for Token Bus networks.
IEEE 802.5
An IEEE standard for Token-Ring-based LANs. There are two types: 4Mbps and 16Mbps. See also Token Ring.
IEEE 802.6 (DQDB)
An IEEE standard for Metropolitan Area Networks.
IEEE 802.7
IEEE 802 technical advisory group on Broadband.
IEEE 802.8
IEEE 802 technical advisory group on FDDI & fiber optics.
IEEE 802.8
IEEE 802 group on integrated data & voice networks.
IEEE 802.11
IEEE standard for wireless Ethernet. It uses a modified version of CSMA/CD called CSMA/CA.
IEEE 802.12
Standard within IEEE 802 for 100VG-AnyLAN.
Jabber
A condition where the transmission of network signals exceeds the maximum allowable transmission time (20 ms to 150 ms). The medium become overrun with data packets caused by a faulty node or wiring connection. See Jabber Lock-Up.
Jabber Lock-Up
The MAU 's ability to automatically inhibit the transmit data from reaching the medium if jabber occurs.
Jam (Ethernet Jam)
This is a term used to describe the collisions reinforcement signal output by the hub/repeater to all ports. The jam signal consists of 96 bits of alternating 1s and 0s. The purpose is to extend a collision sufficently so that all devices cease transmitting.
Lag (Network lag)
The term lag refers to the delay in messages reaching their destination. Often the symptom is long periods of extremely low transfer rate followed by a short time of higher capacity. Lag can occur if you have a bottleneck between you and the computer you are connected to, due to faults in the network, or if the computer on the other side is overloaded.
LAN (Local Area Network)
A communication network that connects all the electronical devices (such as computers, servers, hubs, etc) that are connected to the network.
Latency
This is a measure of how long, on the average, it takes to get a response from something. This can easily be confused with the speed of the link, but one can have a high speed network with also high latency, for example satellite links. Generally it is more important with low latency links than high speed links for normal usage. For file transfers however, high speed is preferrable.
LEVEL system (Level 1 to 7)
A similar cable specification to the Category system. They are now harmonized up to level 5. Anixter Inc. has announced a Level '97 Program:
MAC (Medium Access Control)
Also known as hardware address. The unique numeric identifier of a Ethernet node. It consist of 6 pairs of hexadecimal numbers. See the OSI-model.
MAU (Medium Attachment Unit)
A device used to couple the DTE to the transmission medium.
MDI (Medium Attachment Interface)
The mechanical and electrical interface between the cable medium and a 10BASE-T MAU.
MDI-X (Medium Attachment Interface-Cross Over)
Same interface as MDI but with crossed pairs. It is used in a 10BASE-T hub when connecting to a 10BASE-T MAU.
Multicast
One to many sending of packets on networks. There is a special IP-number range allocated to this. 224.0.0.0 through 239.255.255.255. There is also a special correlation between MAC addresses and this block. The IANA owns an ethernet adress block, 00:00:5E:00:00:00 - 00:00:5E:FF:FF:FF, of which 23 bits of the IP multicast adress is mapped to.
Multimode fiber
Fiber optic cable designed to carry multiple signals set apart by frequency or phase. Use this if you are planning to use fiber in your LAN. The core is much larger than singlemode fiber, usually 25 to 200 µm, and is used with LED sources at wavelengths of 850 and 1300 nm which makes the transmitter cheaper compared with singlemode.

The fiber core may be either step index or graded index:

Step index fiber has a uniform refractive index within the core and a sharp step-like decrease in refractive index of the core and cladding. Graded index fiber has a core with many layers of glass each having a lower index of refraction as you go outward from the axis. This reduces dispersion or fading of the transmission.

NEXT (Near End Crosstalk)
Signal distortion as a result of signal coupling from one pair to another at various frequencies.
NFS (Network File System)
A protocol to share filsystems across networks. Using this several machines can mount the same filesystem, making it look exactly the same for users logging into any of those computers. One of the pure layer 7 protocols, and runs over UDP normally.
NDIS (Network Driver Interface Specification)
A software specification used in many operating systems, such as LAN Manager, Win NT, etc., to create drivers for network adapters. NDIS drivers support multiple protocols and multiple adapters. See ODI.
NIC (Network Interface Card)
A plug-in expansion board that enables computers to send and receive data through the network.
NIS (Network Information Services)
The protocol, originally developed by sun, is used for managing configuration files from a central point across a number of computers. Commonly used together with NFS.
Node (Network node)
A computer, hub or other device in a network.
ODI driver (Open Data-Link Interface)
A MAC-level specification developed by Novell® and Apple® computer. ODI drivers support multiple protocols and multiple adapters. See NDIS.
OSI-model (Open Systems Interconnect)
An ISO network architecture.
Layer Area Description
7 Application User applications software
6 Presentation Data representation and conversion
5 Session Comm. between applications across network
4 Transport provides a transparent, logical datastream
3 Network Routing and flow control
2 Data Link Consist of two sub-layers: 2a and 2b
2a Logical Link Control error detection, correction and retransmission
2b Medium Access Control Sub-layer between software and hardware
1 Physical All the network hardware
OSPF (Open Shortest-Path First)
A routing protocol developed by the IETF as a replacement for RIP as Interior Gateway Protocol. The now most common routing protocol on the Internet.
Packet (Ethernet Packet)
The unit of information transmitted over the network, consisting of a preamble (62 bits of alternating 1's and 0's to acquire bit synchronization and 2 bits for Start Of Frame Delimiter), Destination Ethernet Address (6 Bytes), Source Ethernet Address (6 Bytes), Length or Type field (2 Bytes), the data being transmitted (46 - 1500 Bytes), and a code that allows testing for correct transmission (Frame Check Sequence, 4 Bytes).
PAP (Password Authentication Protocol)
With this protocol, the client (the machine that needs to authenticate itself) sends its name and a password, in clear text, to the server. The server returns a message indicating whether the name and password are valid. See CHAP.
PPP (Point-to-Point Protocol)
Provides a method for transmitting datagrams over serial point-to-point links. See SLIP.
RARP (Reverse Address Resolution Protocol)
The TCP/IP protocol a (diskless) machine uses at startup to find its IP address. Is very uncommon nowdays as it is mostly replaced by BOOTP or the newer DHCP.
RJ45 connector (Registered Jack)
Also known as TP-plug. This connector is a 10BASE-T standard for connecting UTP cabling. They are inexpensive and easy to install.
Front view pinout with the cable on the backside:
 _______/---\_______
 |                 | 
 | 1 2 3 4 5 6 7 8 |
 |                 | 
 -------------------
RIP (Routing Interchange Protocol)
One protocol which may be used on LANs simply to pass routing information between gateways/routers. See OSPF.
SAF switching (store-and-forward)
Store-and-forward switching means receiving each packet before sending it on. It do not transmit either runts or erroneous packets. See CT switching.
Single mode fiber
Fiber optic cable designed to carry the single wavelength selected for transmission. Best used when clear transmission for long distances is required (between 2 and 10 km). Uses a laser sources at 1300 and 1550 nm which makes the transmitter more expensive compared with multimode.
Subminiature type A (SMA)
Single fiber optic connector for use in fiber networks. Not so common anymore.
SMTP (Simple Mail Transfer Protocol)
The TCP/IP standard protocol for transferring electronic mail messages from one machine to another. SMTP specifies how two mail systems interact and the format of control messages they exchange to transfer mail.
SLIP (Serial Line Internet Protocol)
SLIP is a de facto standard, commonly used for point-to-point serial connections running TCP/IP. It is defined in RFC 1055. Now mostly replaced by PPP.
Square Connector (SC)
Dual fiber optic connector for use in fiber networks. Originally designed by Nippon Telephone & Telegraph).
Straight-tip (ST)
Bayonet fiber optic connector. A registered trademark of AT&T.
Straight Thru patch cord (for Ethernet 10BASE-T)
cable wiring is: 
       /--TD+  1 White/Orange
pair 1 \--TD-  2 Orange
       /--RD+  3 White/Green
pair 2 \--RD-  6 Green

See also Crossover Cable.

Switch (switched ethernet)
A hub-based implementation in which each port has the full 10 Mb/s bandwidth of Ethernet available to the attached station. Contrast to a standard Ethernet 10BASE-T hub in which the 10 Mb/s bandwidth is shared by all attached stations. Accomplished through use of internal switching technology which is capable of forwarding multiple Ethernet frames simultaneously between different pairs of ports. Uses standard Ethernet CSMA/CD protocol on each port and does not require a change in the Network Interface Card of the attached stations. Collisions Can still occur if multiple stations try to send to same port at same time. Some switches have both 10 Mb/s and 100 Mb/s ports and/or have CT switching. Compare with 100VG-AnyLAN hub.
T568B (Standard EIA/TIA wiring pinouts for LAN cables.)
Also called AT&T specification, previously called 258A. The most common connector used is RJ-45. 
	 /--T2         1 White/Orange
   pair2 \--R2         2 Orange
	/-------T3     3 White/Green
       /         /-R1  4 Blue
 pair3 \  pair1  \-T1  5 White/Blue
	\-------R3     6 Green
	 /--T4         7 White/Brown
   pair4 \--R4         8 Brown
Translation (Protocol Translation)
The protocol translation software attempts to provide transparent protocol translation between systems running different protocols.
Transceiver (Ethernet Transceiver)
A device used in a Ethernet LAN that couples DTE equipment to other transmission media.
UTP (Unshielded Twisted Pair)
Two insulated copper wires twisted together to reduce the potential for signal interference between pairs. Twisted pair is the most common of transmission media. See the Category system.
I don't take any responsibilty if you screw up using these facts. These facts is only what I have found at the net and some of it is my own experiences... This page is always under construction.
Please mail me if you have any comments.