10BASE-2
Also known as network coax bus, backbone cable or called ThinNet. Thin coax cable is similar to but of higher quality than your home TV and VCR cable. The cable should be clearly marked with RG-58/U stamped on the casing. It is usually quarter-inch coax cable and connects to your network with a BNC connector. This cable is reasonably flexible and is very reliable. While it is more expensive than 10BASE-T cable, it is often the choice for small to medium networks using a bus topology.
10 BASE-T CABLE
A popular Ethernet cable using twisted-pair wiring with RJ-45 plugs at each end. Category 3 10 BASE-T cable is used with 10 Mbps Ethernet networks.
10 Mbps
10 Megabits per second; standard Ethernet operating speed. (Also called bandwidth.
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100 BASE-TX CABLE
An Ethernet cable system using Category 5 twisted-pair wiring with RJ-45 plugs at each end. Used with 100 Mbps Fast Ethernet networks.
100 Mbps
100 Megabits per second; Fast Ethernet operating speed. (Also called bandwidth.)
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A
ACTIVE CONTENT MONITORING/FILTERING
Once connected to the Internet an individual undertakes a degree of risk from computer viruses, malicious Java or ActiveX, and more. Tools that perform active content monitoring examine material entering a computer/network for potentially damaging content, cross-referencing what they scan with continuously updated definition libraries. The impact of allowing malicious content to enter a networked unchallenged can vary form suffering mild annoyances to extended network downtime and loss of stored material.
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ADDRESS LEARNING
Each mode on a network has a unique node address automatically assigned to it (embedded in the adapter card). Switches “learn” this address to enable accurate transmission to and from each node.
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ANTI D.D.oS. TOOLS
Anti D.D.o.S. (Distributed Denial of Service) Tools identify baseline network usage and monitor for anomalies indicative of D.D.o.S. attacks. Once an anomaly is reported, the tool attempts to determine if the upsurge in usage is legitimate or the result of an attack and recommends preventative measures.
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AT&T 5ESS
A digital central office switching systems. It is typically used as an “end-office,” serving local subscribers.
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AUTHENTICATION
Authentication is the process of determining whether something or someone is who or what it is declared to be. The most common form of authentication is the use of logon passwords, the weakness of which is the passwords can often be forgotten, stolen or accidentally revealed. The tokens in this category offer more stringent forms of authentication so that users need to have both something (the token) and know something (the PIN or password) to gain access.
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AUTHORIZATION
Authentication asks the question of "Who are you?" whereas Authorization addresses the question of "Are you allowed to do that?" Policy-based authorization servers allow applications, usually web servers, an ability to centralize authentication and authorization tasks. A Security Manager defines authentication methods (e.g. passwords) users and access controls. Each time a user wishes to access a resource the application queries the authorization server which refers to the policies and the rules to answer the query.
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AUTO PARTITIONING
A feature on some networks a device that isolates a node within the workgroup when the node becomes disabled, so as not to affect the entire workgroup or network.
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B
BACKBONE
The main cabling of a network that all of the segments connect to. Typically, the backbone is capable of carrying more information than the individual segments. For example, each segment may have a transfer rate of 10 Mbps (megabits per second: 1 million bits a second), while the backbone may operate at 100 Mbps. A backbone network is often constructed using thin Ethernet.
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BAUD
An older term meaning the rate of speed of a modem. Baud is often confused with bps, or bits per second. (Actually, a 1200 bit per second modem runs at 300 baud.)
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BANDWIDTH
The term bandwidth is loosely used in networking terminology to describe the rate at which a network can transfer data. Standard Ethernet operates at 10 Mbps. Fast Ethernet operates at 100 Mbps.
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BASIC RATE INTERFACE (BRI)
One of two subscriber interfaces for ISDN. With BRI you get two bearer (B) channels of 64kbps each and a data (D) channel at 16kbps. The two B channels are used for voice; video or high-speed data while the D channel is used for signaling and low speed data transmission. Also commonly known as 2B+D.
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BEARER CHANNEL
A bearer channel is a channel, which carries data, voice, images, or any other information.
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B-CHANNEL
A B-channel is a 64 kilobits per second bearer channel that transports data, voice, images, or any other information.
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BNC CONNECTORS
A BNC connector is a high quality connector found on high-end electronic equipment. It is somewhat similar to the “RCA jack” found on most new TV’s and VCR’s. The BNC connector must be aligned carefully, pushed into place and twisted clockwise to lock in place, making a very secure connection. BNC/coax cable connections do not provide connection status information between your computer and the network connection. Terminate all open ends of a BNC connector to prevent signal bounce.
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BNC PORTS
Also called 10BASE2 or ThinNet. See 10BASE 2 for more information.
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BONDING
Bonding is the act of combining two 64kbps B-channels to derive a 128kbps channel. Done by establishing two B-channel circuit switched calls and combining them in the customer’s equipment (using Multi-link PPP or the bonding specification) or by associating multiple B-channels in the network (multi-rate services). If you make a long distance call using two bonded channels, you will be charged doubly-once for the “phone call” on each channel.
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BRIDGE
Bridges are used to connect separate workgroups (subnets) together. Most bridges identify and keep track of the location of the nodes on each network and allow only necessary traffic to pass through. The bridge directs the destination and source of information.
If a packet of information is flawed, the bridge filters or drops the packet, but if it contains the entire proper source, destination and other information, it will forward the packet. Bridges can even connect both 10 Mbps and 100 Mbps speed networks together.
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BROADCAST
A network transmission sent to all nodes on the network.
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BROADCAST STORM
Network messages that overload the network capacity. Broadcast storms also occur when old and new TCP/IP routers are on the same network.
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BUS TOPOLOGY
A networking setup in which a single cable, such as thin Ethernet, is used to connect one computer to another like a daisy chain to carry data over a network.
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C
CABLE STANDARDS
Networking standards specify cable types for use in 10 Mbps and 100 Mbps Ethernet networks. Category ratings depict the quality or ability to carry data; the higher the category, the better the cable, and therefore, more reliable data. UPT cable should be stamped with the rating (category) clearly marked on the plastic covering.
Your home phone cabling is likely a Category 1 and uses RJ-jj connectors; smaller that the RJ-45 used in Networking. Some commercial installations use Category 3 cabling for telephone connections. Network connections cannot be made with Category 1; use only Category 3 or 5.
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CASCADING
Connecting hubs together with 10 BASE-T cabling; sometimes requires a crossover cable. Also called daisy-chaining.
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CATEGORY 3 CABLE
A 10 BASE-T unshielded twisted-pair cabling type commonly used in today’s 10 Mbps Ethernet networks. Never use with 100 Mbps Fast Ethernet networks.
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CATEGORY 5 CABLE
A higher grade of unshielded twisted-pair cabling required for networking applications such as 100 Mbps Fast Ethernet. This cable grade can be used successfully for 10 Mbps operation, but it is lightly more expensive that Category 3. If you will be upgrading to 100 Mbps in the future, you should consider installing your network with Category 5 cable now. It is most commonly found in buildings that were wired within the last five years.
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CERTIFICATE AUTHORITY
A CA (Certificate Authority) is an organization that issues and manages security credentials and public keys for message encryption and decryption. This is an essential part of a public key infrastructure (PKI) because it manages the process of issuing and verifying the certificates used to grant people and systems access to other systems. These certificates include keys that help to strengthen authentication, privacy and non-repudiation.
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CLIENT
A computer connected to a network or shared resource server.
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CLIENT SOFTWARE
Web browsers such as Internet Explorer*, Navigator*, Mosaic*, etc., are all client software programs used for accessing the Internet. Each client must have software compatible with the server in order to communicate properly.
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CLIENT/SERVER
A network computing system in which individual computers (clients), use a central computer (server) for such services as file storage, printing, and communications.
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COAXIAL CABLE
Thin or thick coax cable used in Ethernet networking, usually in a bus topology or backbone use. (Also called 10 BASE 2 or ThinNet.)
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COAX
Coax cabling is similar to but higher quality than cable TV or antenna cabling. There are two types of coax cable used on a network: Thin (10BASE 2) and thick (10BASE 5). Because 10 BASE 5 is rarely used in small networks, only thin Ethernet is being described. Remember, in a coax bus or backbone network, if a single connection fails, the entire network may be disabled.
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COLLISIONS
Two packets sent over the network segment simultaneously will collide and be rejected. Ethernet will automatically resent them at altered timing to ensure proper receipt..3
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COMMUNICATIONS SOFTWARE
Software (such as email and faxing software) that allows users to send or receive data remotely.
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CPU
The term Central Processing Unit started out meaning the brain or processing chip of the computer and has evolved to mean the box of computer. On a network, known as a node.
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CROSSOVER CABLE
A cable in which receive and transmit lines (input and output) are crossed. Crossover cables are sometimes needed to connect hubs together.
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CROSSTALK
Signal noise passed between network cable or devices.
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D
D-CHANNEL
A D-channel is a data channel for signaling between the user and the ISDN network. A PRI D-channel is 64kbps, a BRI D-channel is 16kbps. The D-channel can also be used to carry packet switched data at up to 9,600bps.
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DATABASE SECURITY
Software that identifies security attributes within relational databases including logins/accounts, passwords, roles, and privileges. Requisite functionality includes vulnerability assessment, security administration, and enhanced auditing. These products may optionally provide real-time detection and alerting capabilities for unauthorized access or changes to the underlying data base on pre-defined rules.
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DATA TRANSMISSION SPEED
The number of bits that are transmitted per second over a network cable.
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DEDICATED SERVER
A computer on a network that is assigned to function only as a resource server and cannot be used as a client.
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DEVICE
In this book, device refers to a piece of networking equipment such as a hub, switch, repeater, bride, router, etc.
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DRIVER
A software program that allows a computer system to communicate with other equipment. The driver manipulates the hardware in order to transmit data to the equipment.
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E
EMAIL
Method of sending electronic messages using modem and communication software.
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ENTERPRISE SECURITY ADMINISTRATION
Tools providing enterprise-wide security administration apply a given security policy across an entire organization, ensuring all users of that enterprise's network will be subjected to the same rights and restrictions. These systems are especially valuable in granting new users access to all appropriate systems and, more importantly, removing users from all systems if they are terminated.
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ENTERPRISE SECURITY POLICY IMPLEMENTATION
ESPI enables security managers to automate each step of security policy management from a central console including creating, editing, approving, publishing, distribution, education, compliance, reporting and maintenance. These tools enforce awareness, assess employee understanding, track incidents and measure compliance, which helps organizations improve management of IT risks without overburdening limited staff.
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ETHERNET
Networking standards originally developed in 1973 by Xerox and formalized in 1980 by DEC, Intel, and Xerox, which transmits data at 10 Mbps using a specified protocol. The most popular LAN technology in use today. (See Fast Ethernet.)
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ETHERNET ADDRESS
Each Intel InBusiness product and networking devices such as Network Adapter cards, has its own unique Ethernet address pre-programmed. The address is obtained automatically when required by network transmission. This number identifies the node or networking device as a unique communication item and enables direct communications to and from that particular computing device.
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F
FAST ETHERNET
An Ethernet networking system, which transmits data at 100 Mbps. Also known as 100BASE-TX, it is similar to 10BASE-T Ethernet, only 10 times faster and higher quality.
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FAX SOFTWARE
Communication software that allows users to create, send, receive, and print documents as faxes from their personal computer.
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FILE & SESSION ENCRYPTION
Encryption is a process through which data is transferred into a form whereby it cannot easily be intercepted and understood by unauthorized persons. Sophisticated computer algorithms are used to encrypt the files, then decrypt them when they are needed.
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FILE SERVER
A dedicated network computer used by client computers to store and access software and work files.
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FILTERING PROCESS
An Ethernet switch or bridge process that reads the contents of a packet and discards it if it does not need to be forwarded.
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FIREWALLS
A firewall is a system or group of systems that enforces an access control policy between two networks.
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FULL-DUPLEX
Two-way simultaneous communication. The ability to send and receive electronic signals at the same time. Most networks run at half duplex. (See half-duplex.)
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G
GROUP 4 FAX
The latest and fastest international standard for facsimile machines. It specifies a machine which operates at 64Kbps, which can only work on a digital channel and which takes six seconds to transmit a 8 ½ x 11 inch page. The Group 4 standard was promulgated in January 1987. Group 4 fax machines are designed to use one of the 64,000 bits per second B (Bearer) channels on ISDN.
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H
HALF-DUPLEX
Two-way communication at any one time. The send and receive portions of electronic communication are separate. Half-duplex is the standard mode.
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HARDWARE
Components of a computer system including monitors, hard drives, CD-ROMs, printers, keyboards, a mouse, portable hard drives, modems, etc.
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HOP COUNT
A term used when counting components and sections of wire in an Ethernet network to determine whether Ethernet compliance has been met.
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HUB
Hubs are also called a wiring but or concentrator. It’s the central connectivity point in a star network, workgroup or subnet. A hub allows each node to communicate with all other connected nodes. Connected nodes provide their own power; on the hub has its own power supply. Hub status lights help to monitor the network. Most hubs are plug and play; no software is necessary to install. Two or more hubs can be connected to enable network expansion easily and inexpensively. Hubs can also be connected together by a bridge. (See repeater.)
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I
INTERNET
A worldwide network of information, which can be accessed by modem and communication software through an Internet Service Provider.
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INTERNET WORK
A large, multi-segment network that includes communication between two networks or two types of networks, Bridges or routers are the devices that join LANs.
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INTRANET
While similar to the Internet, this is a private, network within a company or other organization that does not run on the Internet. It usually looks just like the Internet, but is separated by a firewall. It is usually set up with locations and pages and functions with the email system. It is used for a variety of inter-company purposes including posting company policy, announcing job openings, listing engineering projects and schedules, meeting announcement, posting sales, benefits coordination, etc.
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INTRUSION DETECTION HOST BASED
A host-based intrusion detection system is software that monitors a system or applications log files. It responds with an alarm or a countermeasure when a user attempts to gain access to unauthorized data, files or services.
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INTRUSION DETECTION NETWORK BASED
A network-based intrusion detection system monitors network traffic and responds with an alarm when it identifies a traffic pattern that it deems to be either a scanning attempt or a denial of service or other attack. It is quite useful in demonstrating that "bad guys" are actually trying to get into your computers.
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IP
Internet Protocol. TCP/IP protocol for packet forwarding. (See also TCP/IP)
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IPX
(Internet Packet exchange.) A Novell NetWare protocol similar to IP (Internet Protocol).
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ISA
Industry Standard Architecture. The most common bus architecture on a DOS based computer. Also called classic bus. A unique network interface card slot specifically designed for an ISA card on the motherboard of a computer.
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ISDN
Integrated Services Digital Network. Digital switching and carrying data, voice, computer transmissions, music and video at speeds exceeding that of traditional analog telephone lines.
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J
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K
KILOBIT
One thousand bits of data. 240 kilobits per second means 240,000 bits of information are being transmitted per second over a network (240 Kbps).
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L
LAN
Stands for Local Area Network. A network in a localized (not remote) location that allows users to share files, printers and other print services.
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LEDs
Light emitting diode. Small indicator lights on electronics and networking devices that provide indication of status and other information about the device.
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M
MANAGED SECURITY SERVICES
Vendors providing managed security services assume a percentage of the security administration tasks for an enterprise's network, allowing administrators to concentrate on other job responsibilities.
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MBPS
Millions of bits per second.
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MEDIA
In this book, networking wiring such as 10 BASE-T and 100 BASE-TX UTP cable, and coax cable is referred to as media. Other media includes radio wave and fiber optic.
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MEGABIT
One million bits of data. (10 Megabits per second, or Mbps, means that 10 million bits of data are being transmitted over the network per second.)
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MODEM
An acronym from “modulator and demodulator.” It covers analog to digital and digital to analog signals. A communications product that sends computer transmission over a standard telephone line at preset speeds.
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N
NATIONAL ISDN-1
National ISDN-1 is a specification for a “standard” ISDN phone line. It is based on technical references (TRs) specified by Bellcore that lay the groundwork for a national ISDN infrastructure. Bellcore issued the National ISDN-1 document, SR-NWT-001937, Issue 1, in February 1991. The idea of National ISDN-1 is that it be a set of standards, which every manufacturer can conform to.
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NetBIOSS/NetBEUI
The acronym for NetBIOS is ‘network based input/output system.” The acronym for NetBEUI is “NetBIOS extended user interface.” Often used in Microsoft’s LAN Manager and Windows NT protocols.
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NETWORK
The means by which computers and other networking devices are connected together so that print services, files, equipment, and software applications may be shared.
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NETWORK ADAPTER CARD
Network Adapter Cards (also called Network Interface Cards, or NICs) are the first and most basic item needed to begin your network. Some newer computers have cards built into the system. If your computer does not, you can add one of these small PC boards to your computer in a matter of minutes. The cards install into a slot on your motherboard, just like a sound card or a modem card. Several types are available; make sure you get the one made for your computer type. Your adapter card supplier can advise you on what type will work with your computer.
A network interface card provides the necessary link between your computer and your network. It converts your data into a format that an Ethernet network can accept and read. These small cards contain the connectors needed to link your computer to either a hub or another computer. Configuration software comes with the adapter to enable your computer type to work with the network.
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NETWORK AUTHENTICATION
These tools take several approaches to improving the ability of your systems to differentiate between people who should and should not have access.
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NIC
Network Interface Cards are available in 10 Mbps and dual function 10/100 Mbps cards. Dual function 10/100 Mbps cards are the most cost effective if you are connecting to a 10 Mbps network now but planning to move to a Fast Ethernet 100 Mbps network in the near future.
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NETWORK OPERATING SYSTEM
NOS. A special application that allows computers and other devices on the network to send and receive information.
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NIC
Network Interface Cards, also called adapter cards. They serve as the interface between the computer and the network cable for sending and receiving data.
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NODE
Computing equipment such as a computer, printer, modem, server, etc. that is connected in a LAN containing the capability of communicating with other network nodes, and networking devices such as hubs, switches, routers, bridges, etc.
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NT-1 NETWORK TERMINATION TYPE 1
This is the device that connects to your wall jack and connects the line from the telephone company central office to the customer premises. It provides the interface between the ISDN loop and the terminal adapter or what other ISDN customer premises equipment you’re using. Some ISDN CPE equipment has an NT-1 built in. Some don’t.
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P
PACKET
A unit of transmitted information that follows specific protocols and contains codes that include precise sending and receiving of information from one networked node to another.
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PACKET SWITCHED DATA
Packet switched data is data that is broken down into standard sized packets then sent through the network. The packets each carry the destination address and the information required to reassemble them when they reach their destination.
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PC CARD
Communication cards roughly the size of a credit card that fit into the small PC Card slot of portable computers or other networking devices. Formerly called PCMCIA cards, these adapters offer Ethernet access, data/fax/modem capability and other services to portable computers. Laptop computers can connect to an Ethernet network with the help of the small insert able card. A small connector on one end of the card connects to the PC Card slot of a laptop. A connector on the opposite end connects directly to the Ethernet network hub.
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PCI
Peripheral Component Interconnect bus architecture. This is a 32/64 bit local bus architecture on the motherboard of a computer inside a PC or Macintosh, designed by Intel. It is used to connect network interface cards. Its operation is faster than an ISA or EISA bus.
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PEER-TO-PEER
All connected computers on this network type communicate directly without the use of a dedicated server. (See Client/Server.)
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PERIPHERALS
Equipment such as disk drives, CD-ROM drives, modems, printers, fax machines, keyboards, etc. that are connected to a computer.
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PLUG AND PLAY
An identifying specification in the PC market that assures the user that the product is as simple or automatic to install as possible; both hardware and software installation.
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PORT
A connector on your computer or networking device that is used to attach the cabling. A connector type includes RJ-11 (telephone connection), RJ-45 (communications connection), and BNC (locking-type connector for coax or backbone connections). A typical port would be used to connect the adapter card in your computer to the hub, or the modem to your Internet Station, or any of the connections on a hub, switch, or router.
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PRIMARY RATE INTERFACE (PRI)
ISDN PRI is 23B+D or 30B+D. At 23B+D, it is 1.544 megabits per second. At 30B+D, it is 2.048 megabits per second. The first, 23B+D is the standard T-1 line in the U.S. which operates on two pairs, but is typically delivered on fiber. The second 30B+D is the standard T-1 line in Europe, which also operates on two pairs. You can subdivide the PRI ISDDN channel of 1.544 megabits per second into 23 bearer (B) channels of 64kbps each and a data/signaling (D) channel at 64kbps. If you subscribe to multiple PRI lines you can use one D channel to control the signaling on multiple PRI lines and thus derive 24 B channels out of all of them, barring the one you need for signaling.
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PROTOCOL
A set of procedures or rules for sending and receiving information on a network.
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PVC
Permanent Virtual Circuit
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R
REAL-TIME SECURITY AWARENESS/INCIDENT RESPONSE
RTSA allows the security manager to see what is happening across the enterprise among multiple vendor security products and sources in near real-time from a central console. RTSA helps reduce the number of personnel whose time must be devoted to monitoring multiple security products and sources.
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REPEATER
Repeaters are used in a star topology when the distance in the network expands in a network expands to the point that it exceeds Ethernet networking standards but still must grow. A repeater is similar to a hub with the exception that is amplifies and retimes the signals being sent across the network. Repeaters monitor connected workgroups. When a malfunction occurs in a workgroup, a repeater will disconnect the malfunctioning computer from the network. The same problem in a bus topology would disable all nodes attached to that segment.
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RING TOPOLOGY
A basic networking topology where all nodes are connected in a circle, with no terminated ends on the cable, like token ring.
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RISK ASSESSMENT
Risk is a combination of the likelihood that an incident will occur and the damage that will result. Risk Assessment provides an understanding and analysis of these two factors using processes and tools. Organizations usually face an insurmountable number of potential vulnerabilities. Risk Management determines which risks should be accepted, assigned or avoided (mitigated).
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RJ-11
A standard telephone connector.
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RJ-45 PLUG
The connector on the end of 10 BASE-T or 100BASE-TX twisted-pair cabling; looks much like a telephone plug.
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RJ-45 CONNECTORS
10BASE-T cable uses RJ-45 connectors that connect to RJ-45 connector ports on most networking products. RJ-45 connectors are similar in design to your modular telephone connectors; just a little larger. They click quickly and easily into the port, making a very secure connection.
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RJ-45 JACK
The connector on the back of a computer or printer that accepts the RJ-45 plug; likes much like an RJ-11 telephone jack, but is larger.
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RJ-45 STRAIGHT-THROUGH PORTS
A straight-through port is the standard port on most hubs, switches, brides, etc. It may also be called a 10BASE-T port. It allows direct connection from a node to the connecting equipment. The media used is a 10-BASE-T cable with RJ-45 modular connectors. You cannot tell by looking at the port whether it is a standard or crossover port. Your manufacture’s documentation will detail the ports and inform you of port types being used.
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RJ-45 CROSSOVER PORTS
A crossover port is usually marked with an "X" for easy identification. This specially configured RJ-45 port is provided on some networking devices to allow easier connection when cascading (connecting) from one hub or switch to another; for example, when connecting multiple hubs or multiple switches, allowing expansion of the network. When using a device with a crossover port, a standard, straight-through cable is all that is required. The equipment manufacture’s documentation will inform you when this special type of port is present on your networking device and what type of cable is needed.
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ROM
Read only Memory.
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ROUTER
Router filter network traffic and connect different protocols to ensure that the file is routed to the correct location. Because of this filtering, a router is slower that a switch or bridge, but will perform a valuable function if filtering is required. Unlike direct bubs and switches, routers can offer network management services, such as zone configuration and control.
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S
SECURE WEB SERVERS
These tools offer web services in environments that have been engineered to minimize the number of security holes.
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SECURITY APPLIANCES
These hardware/software combinations offer firewall and sometimes other services such as network load management in a single purpose offering. Because they have very limited operating system function, they are generally easier to manage, cheaper, and less subject to common hacker attacks than firewalls installed on general purpose UNIX or Windows NT computers.
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SECURITY SERVICES: PENETRATION TESTING
Consulting organizations simulate real-word hacking and social engineering attacks on an enterprises' network and systems to determine where weaknesses lie, and offer advice on how those weaknesses may be addressed in order to beef-up security.
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SECURITY SERVICES: POLICY DEVELOPMENT
Consulting organizations that have worked with many organizations have templates with which they can quickly establish for all aspects of computer security from acceptable use to email to extranets to PKI.
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SEGMENT
In regards to cabling, the length of cable on a network between two terminators.
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SERIAL PORT
Communications path through which data is transferred in bytes. Only one wire each is available for transmitted and received data; character bits are sent sequentially between two nodes, one at a time.
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SERVERS
A server can be a low or high capacity computer that provides various resources. A typical server contains several hard disk drives, a tape backup and a CD-ROM drive. It can be used to help share resources such as printer, fax machines, modems, e-mail and connections to the Internet. It is often used to store database information, files, file backup, and multiple software programs (site licensed) for access by “client” computers. Computers connected to a server are called “clients.” The functions of the server can be administered and controlled, and can provide security to network users. Several types of servers are available either singly, in any combination, or in total: file and print server, application server, mail server, directory services server, and communications server.
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SERVER-BASED NETWORK
A network in which all client computers use a dedicated central server computer for network functions such as storage, security and other resources.
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SHARED DATA
Files on the server that can be shared across the network.
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SHARED ETHERNET
Standard 10 BASE-T Ethernet method of sending data to a hub, which then rebroadcasts this data to every node or port on the network until it, reaches all nodes. (See switched Ethernet.)
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SHARED RESOURCES
Files, printers, peripherals and other services that can be shared across the network.
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SIGNAL BOUNCE
When a bus topology network cable has not been properly terminated at each end of every open cable, the signal from the network will travel from one end of the cable to the other and then will continually bounce back the way it came.
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SIGNALING
Signaling is a term referring to the way that information pertaining to call set-up is passed from node to node in the phone system. The most commonly known form of signaling is the frequencies associated with touch-tone. These frequencies are your POTS phone’s way of signaling to the central office the information that the C.O. requires to process your call. With ISDN, all signaling is done on a separate data circuit (out of band), using a standard known as Signaling System 7.
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SINGLE SING-ON
These software packages allow users to get access to multiple computer and applications without learning many different passwords. Single sign-on tools generally do not change the underlying applications, but hide their differences through a layer of software.
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STAR TOPOLOGY
A networking setup used with 10 BASE-T or 100 BASE-TX cabling. Each node on the network is connected to the hub like points of a star. (See bus topology.)
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STORE-AND FORWARD
The most accurate data transferring technique used by switches, it examines each packet of a transmission to verify accuracy, and ensure bad or misaligned packets are eliminated, and then sends good packets to their destination. When the network is busy, packets are stored until the network is able to carry the traffic and packets are transmitted without error.
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SUBNET
A network segment connected by hubs or repeaters. Subnets can stand-alone, can be connected to other subnetworks to form a small LAN, or can be connected to a larger network.
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SWITCH
Similar to but more sophisticated than a hub, a switch learns network addresses automatically, providing a private line to the network. A node or a fully populated hub can connect to a switch. A switch is a key component in network expansion. It divides a large network into smaller segments. Adding a switch often improves the speed of a network that has become bogged down and over used, and helps eliminate network errors.
A switch also enables a network transmission to be directed to a specific node on the network instead of being transmitted to all users, like on a hub. The type of transmission control on the switch monitors the network activity, sends the data, and test is to ensure a complete transmission. This is called “store-and forward.” (See also bridge.)
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SWITCH ETHERNET
Unlike shared Ethernet, it provides a “private” connection between two nodes on a network, speeding up the rate at which data is sent along the network and eliminating collisions. (See Shared Ethernet.)
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SWITCHED 56
A switched data service which lets you dial someone else and transmit at 56 kilobits per second. It is a circuit switched service, letting the user transmit data at full duplex, digital synchronous 56 Kbps for usually the price of a phone call. Switched 56 can be delivered on one pair or two pairs. Switched 56 are used for videoconferencing, high-speed data transfer, digital audio broadcasting, Group IV fax and remote LAN access for telecommuters. Switched 56 data service is probably the most widely used switched digital service available in North America.
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TCP/IP
Transmission Control Protocol/Internet Protocol. Originally two separate protocols, now they are almost always used together. The term TCP has evolved to mean the family of common Internet protocols used by industry. It is the protocol for the Internet. It became widely accepted first in UNIX environments. It is a networking protocol with the ability to connect may widely different elements.
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TERMINAL ADAPTER- (TA)
The ISDN device that connects to your computer, analogous to a modem. The TA does not perform the analog to digital (and vice-versa) conversion that a modem does, but enables your computer to communicate over digital telecommunications facilities.
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TERMINATOR
A 50 ohm resistor at each open end of an Ethernet coax cable that absorbs energy to prevent reflected energy back along the cable (signal bounce). It is usually attached to an electrical ground at one end.
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THICK ETHERNET
Also called standard Ethernet or thicknet, it is used with 10 Mbps baseband networking. Often used in a backbone topology or network. Thick Ethernet is heavy, stiff, and difficult to install, and is the most expensive wired cabling used. Uses BNC connectors.
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THIN ETHERNET COAX
Usually quarter-inch black coaxial cable, identified by type as RG-58/u. Sometimes called NETWORK COAX, 10 BASE 2 or thinnet cable. Uses BNC connectors.
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TOPOLOGY
A wiring configuration used for a network; think of it as a layout or structure. Examples are the ring, star, bus, and so on.
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TRANSCEIVER
Derived from transmitter/receiver, a transceiver is a device that sends and receives signals, and can connect a computer to the network, such as a network adapter card. It often provides packet collision detection, too.
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TRUSTED OPERATING SYSTEMS
Because all other security mechanisms rely on the operating system, they can be disabled or circumvented by a successful attack on the o/s. Trusted o/s technology provides the only mechanism to protect the o/s itself from successful attack.
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TWISTED-PAIR CABLE
A cable used for both network communication and telephone communications. Also known as UTP (unshielded twisted-pair), it comes as 10 BASE-T or 100 BASE-TX cable.
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UTP
Unshielded twisted-pair or stranded cabling. It comes in both Category 3 (10BASE-T for 10 Mbps networking) and Category 5 (100BASE-TX for 100 Mbps Fast Ethernet networking). It is thin, flexible and easy to use with the common RJ-45. Two advantages of Twisted-pair networks are the low cost of the cables, and the ease of installation in a star network. Other advantages are its ability to quickly resolve failed connections. This cable type is used with a Star topology. Remember, each segment of wire must not exceed 100 meters (about 328 feet).
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VPNs & CRYPTOGRAPHIC COMMUNICATIONS
A VPN or Virtual Private Network allows secure communications over the public internet. It saves money in organizations with large mobile workforces or many satellite offices reducing the need to use expensive private telephone networks. .
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VULNERABILITY SCANNERS HOST BASED
These tools check the settings on our systems to determine whether they are consistent with corporate security policies. They are often used by auditors.
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VULNERABILITY SCANNERS NETWORK BASED
Software that simulates the behavior of attackers to learn which of as many as 600 possible weaknesses are present on the system being attacked.
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WAN
Wide Area Network. A very large sophisticated network that extends beyond a single building, and often extends across a city, state or farther.
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WEB APPLICATION SECURITY
Web application security is the protection of your web application and its resources from threats coming from the Internet, such as stealing company assets, falsifying buy/sell transactions, getting private customer data and defacing the site. This is done by detecting and/or preventing the hacking techniques applicable to this domain, i.e. those which can be performed in the presence of firewalls and encryption.
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WORKGROUP
Nodes connected to a hub or switch to form a small communication grouping on the network. For instance, a LAN might have the five accounting people in one workgroup, the shipping/receiving department in another, etc.
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WWW
World Wide Web. Sometimes referred to as W3. It is an incredible body of accessible information available on the many computers around the world and attached to the gargantuan computer networks called the Internet. The Internet’s multimedia service contains countless area of information, documentation, entertainment, as well as business and personal home pages.
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