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Glossary of Networking Vocabulary 1

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10BaseFB
Fiber cable, <_ 2Km [p. 466 CPWW]

10 Mbps; Ethernet [Cisco Glossary]
10BaseFL
Fiber cable; <_ 1Km. [p 466 CPWW}

10 Mbps; Ethernet, <_ 2Km in some cases. [Cisco Glossary]
10BaseFP
Fiber cable <_ 1KM. [p. 466 CPWW}

10 Mbps; Ethernet; <_ 500m in some cases. [Cisco Glossary]
10BaseT
802.3 spec for Ethernet @ 10 Mbps over STP/UTP. Segment <_ 100 m. [CPWW]

2 pr of twisted pair Cat 3,4,5. [www.glossary-tech.com]

data grade.
10 Mbps over cat 3.
16 Mbps over cat 4.
100 Mbps over cat 5.
All very low relative cost. [p. 149 CPWW]
10Base2
802.3 spec for Ethernet @ 10 Mbps over thinnet coax. Segment <_ 185 m. [CPWW]

Data grade; medium cost. [p 148. CPWW]
10Base5
802.3 spec for Ethernet @ 10 Mbps over thicknet coax. Segment <_ 500 m. [CPWW]

Data grade; medium cost. [p. 148 CPWW]
56K technology
Serial transfer of data over analog modems theoretically <_ 56 K BPS, e.g., x.2 and K56flex and eventually V.90. [CPWW]
100BaseFX
IEEE 802.3 spec for running Fast Ethernet over fiber optic cable. [CPWW]

Segment <_ 400m. [www.glossary-tech.com]

Data grade; <_2 Km; 10 Gig. Very high relative cost. [p. 149 CPWW]
100BaseTX
802.3u spec, a.k.a., Fast Ethernet for running Ethernet @ 100 Mbps over STP/UTP. [CPWW]

2 pr.; segment <_ 100m. [glossary-tech.com]
100BaseT4
Use of Fast Ethernet (<_ 100 Mbps) over existing CAT3 and CAT4 wiring using all 4 pairs. [CPWW]

UTP. [www.glossary-tech.com]

Also cat 5. <_100m. [p. 466 CPWW]
100BaseVG AnyLan
IEEE 802.12 specification that allows data transmissions of 100 M BPS over Cat 3 (data grade) wiring, utilizing all sets of wires. [CPWW]
1000BaseX
802.3z spec, a.k.a., Gigabit Ethernet for 1,000 Mbps. [CPWW]
ACL
Access Control List
Name given to the list of total rights granted to a particular user through group memberships. [CPWW]
Access layer
In the Hierarchical Model, the layer where the workstation connects to the net. Here hubs reside and workgroups access the network. [CPWW]
[TCP header field:] Acknowledgement #
In TCP/IP header the number of the sequence of data expected to be received next. Sent for error corrections. 32 bits. [p264 CPWW}

@+64 or identifier # of octet that source expects to receive next; i.e., in stream flowing in opposite direction. [p. 204 Comer]
active directory
In MS Win2K, a user, group, security information DB distributed across a Win2K net. [CPWW]
active termination
Used w/SCSI devices to provide a more stable flow of signals across bus. [CPWW]
address
Set of numbers, usually in binary, used to identify and locate a resource or device on a network. [CPWW]
ARP
Address Resolution Protocol
Protocol used to map the IP address to the MAC address.
administrator
Person responsible for control and security of user accounts, resources, and data on a network. [CPWW]
administrator account [in M$ Win NT]
In M$ Win NT the system default account with rights to access everything and to assign rights to other users. [CPWW]
ANDing
Process of comparing bits of an IP address with bits in a subnet mask to determine how a packet will be handled. [CPWW]
anycast address
Address used in ATM for shared multiple-end systems. It allows a frame to be sent to specific groups of hosts (rather than to all hosts as with simple broadcasting). [CPWW]
[OSI] Application layer
OSI layer 7 providing distribution of information services. User access layer. [Reeves & Reeves]

Support for end users and applications using network resources. [CPWW]

User interface to the network, network applications. [CPWW]

No real TCP/IP equivalent. [p115. CPWW]
[TCP/IP] Application layer
OSI Presentation layer. [p. 115 CPWW]
[OSI] Application layer PDU is?
OSI PDU = message
Application log
Log located in M$ Windows NT 4 event viewer that provides information on events that occur within an application. [CPWW]
API
Application Programming Interface
Set of routines that enable a programmer use computer facilities, e.g., sockets, transport layer facilities. [AI]
ARCnet
Token-bus LAN technology used in the 1970's and 1980's. [CPWW]

RG-62 coax, 93 ohm. [p. 16 CPWW]

May a type of thinnet. [p. 145 CPWW]
ADSL
Asymetric DSL
Service transmitting digital voice and data over existing analog phone lines. [CPWW]
ATM
Asynchronous Transfer Mode
Cell based protocol for transmitting/switching voice, data, and video. [Reeves & Reeves]

Used in E3, SONET, T3 for cell relay. Multiple types (voice, video, data) in fixed 53 byte cells. [CPWW].

Connection oriented. [Comer]

Uses fiber. 100 or 155 Mbps. [Comer]

53 byte cell length is at lower level [Comer]
AAL
ATM Adaptation Layer
Protocol which enables ATM net to provide a variety of services. [Reeves & Reeves]

Data transmissions are AAL5. [Comer]
ATS
Asynchronous Transmission Synchronization
Process used in serial data transfer in which start bit and stop bit added so receiving station knows when particular bit transferred, a.k.a., bit synch. [CPWW]
AUI
Attachment Unit Interface
802.3 spec used between MAU & NIC. [CPWW]

Thick-wire Ethernet connector. [Comer]

16 pin D connector. [www.glossary-net.com]
attenuation
Loss of signal experienced as data is transmitted across network media. [CPWW]
backbone
High capacity infrastructure providing optimal transport at each site. [CPWW]

Any network forming central interconnect for an internet. [Comer]
BDC
Backup domain controller
Server in WinNT network configured to provide auxiliary authentication, e.g., user, group, and security services if primary down. [Reeves & Reeves, CPWW]
bandwidth
Rated throughput capacity of a given network protocol or medium. [CPWW]
base bandwidth
Difference between the lowest and highest frequencies available for network signals. Term also used to describe rated throughput capacity of given network protocol or medium, i.e., simple 'bandwidth'. [CPWW]
baseband
Characteristic of any network technology like Ethernet that uses single carrier frequency and requires all stations attached to participate in every transmission. [Comer]
BRI
Basic Rate Interface
ISDN version or line comprising two bearer channels @ 64 Kbps and 1 data channel at 16 Kbps and using copper to provide digital voice and data communications. [Reeves & Reeves]
A.k.a. 2B and D. [CPWW]
baud rate
Speed or rate of signal xfer. Technically it's number of state changes in the carrier wave per second. [CPWW]
bindery
User, group, security information on a NetWare 3.x server. [CPWW]
binding
Process of associating a protocol and a NIC. [CPWW]
bit
Electronic digit used in binary numbering system. [CPWW]
blackout
Total loss of electrical power. [CPWW]
bridge
Device connecting 2 LANs or segments together and where no protocol conversion is needed. OSI layer 2 device. [Reeves & Reeves]
It filters, forwards, or floods based on frame's MAC address. [CPWW]
Operates at physical [sic] network layer. It stores and forwards complete packets unlike repeaters which forward all signals. Unlike routers they use physical not IP addresses. [Comer]
bridging address table
List of MAC addresses kept by bridges. Used when packets received to determine segment addresses before forwarding or keeping. [CPWW]
broadband
Characteristic of any network technology that multiplexes multiple, independent network carriers onto a single cable (usually w/FDM). Uses less cable but is more expensive for connection equipment.
[Comer]
broadcast
Packet delivery system in which a copy of a packet is given to all hosts attached to the network. [CPWW]
broadcast storm
Broadcasts so numerous as to choke network. [CPWW]
brouter
Routes routable protocols at network layer and bridges non-routable protocols at data link layer. [CPWW]
brownout
Short term decrease in voltage. [CPWW]
bus
Path used by electrical signals to travel between CPU and attached hardware. [CPWW]
bus mastering
Bus access method in which NIC takes control of bus to send data through bus directly to memory, bypassing CPU. [CPWW]
bus topology
Linear LAN architecture using common cable w/multipoint connections for the flow of data in serial progression within segment. [CPWW]
[TCP FTP] bye command
Closes the TCP FTP server & returns you to command prompt. [p 349. CPWW]
byte
Set of bits (usually 8) operating as a unit to signify a character. [CPWW]
Cable TV coax type?
RG-59; 75 ohm coax; [p. 16 CPWW]

May be a type of thinnet. [p. 145 CPWW].
caching-only server
Server operating same as secondary server expect no zone transfer when it's started. [CPWW]
CSMA/CA
Carrier Sense Multiple Access with Collision Avoidance
Contention media-access method using collision avoidance. [CPWW]
CSMA/CD
Carrier Sense Multiple Access with Collision Detection
LAN access technique that allows a NIC to sense the medium. transmit a packet, an then detect collisions. [Reeves & Reeves].
It's a contention method [CPWW]
[TCP FTP] CD command
Change directory command for TCP FTP. [p. 349 CPWW]
Centronics connector
Common connector using teeth that snap into place. [CPWW]
CHAP
Challenge Handshake Authorization Protocol
Secure challenge and response security mechanism for verifying user identity. [Reeves & Reeves]
change control
Process in which detailed record of every change made is documented. [CPWW]
channel
Communications path used for data transmissions. [CPWW]
[TCP header field:] checksum
In TCP headers: used for error correction. 16 bits. [p. 264 CPWW}.

@+128. [p.204 Comer].
[UDP header field:] checksum
In TCP/IP headers: contains result of algorithm on length of header & data. 16 bits. [p. 266 CPWW]
CSU
Channel Service Unit
Device connecting line and provides a termination for digital signal. Usually used with DSU. [Reeves & Reeves]

Could be dedicated line or frame relay. [CPWW]
Class A TCP/IP Network
TCP/IP network with addresses 1-127 in 7 bits. Supports subnet <_ 126 with 16,177,214 unique hosts each. high order bit = '0'. [CPWW]
Class B TCP/IP network
TCP/IP network with addresses 128-191 in 2 octets (14 bits). Subnets <_ 16,384 with 65,534 unique hosts in 2 octets each. [CPWW]

Two high order bits are 10. [CPWW]

They have 2**8 through 2**16 (256 - 65,536 or 65,534) hosts per network. [?]

16,382 networks. [Encyc of Networking]
Class C TCP/IP network
TCP/IP network with addresses 192 - 223 with 21 bits in 3 octets. Subnets <_ 2,097,152 with 254 unique hosts in each. [CPWW]

Three high order bits are 110. [CPWW]
CIDR
Classless Interdomain Routing
Technique allowing multiple addresses to be consolidated into a single entity. [CPWW]

Addressing and routing scheme using group of contiguous class C addresses in place of a class B address. [?]
client
Node that requests a service from another node on network. [CPWW]
Client - server
The model of interaction in a distributed system in which a program at one site (client) sends a request to a program at another site (server). [Comer]
clustering
Server fault tolerant method which is implemented in WinNT networks to provide seamless failover upon server failure. Two servers with similar HW connect to a shared external hard drive cabinet. [Reeves & Reeves]
Coaxial cable
Stranded or solid copper used for transmissions <_ 1 GHz. [Reeves & Reeves]
Insulated and surrounded by braided metal and covered with thick plastic or rubber. Used in cable TV and older bus topology networks. [CPWW]
[TCP header field:} code bits, a.k.a., control bits
In TCP/IP header:
1st = urgent
2nd = Ack
3rd = Push function
4th = connection reset
5th = sync of seq #
6th = finish indicator

6 bits. [p 264 CPWW]

@+106. they tell how to interpret other header fields. [p. 204 Comer]
Collision
Two frames transmitting simultaneously in an ethernet network and colliding, therefore destroying both frames. [CPWW]
Collision domain
Ethernet segment between managing nodes where only 1 packet transmitted at a time. Switches, bridges, and routers can segment a network into them. [CPWW]
COM port
Connection for serial devices to communicate between devices and motherboard. It requires configuration information, e.g., IRQ, I/O, address, port #. [CPWW]
COM1 port
IRQ 4; 03F8h [p. 370 CPWW]
Which COM port?
COM2 port
IRQ3; 02F8h. [p. 370 CPWW]
COM3 port
IRQ 4; 03E8h. [p. 370 CPWW]
COM4
?
Conflicting devices list
Located in Win95 device manager. Details IRQ or I/O conflicts. [CPWW]
Connection
Abstraction provided by protocol software. TCP provides this between two applications. [Comer]
connectionless protocol
Characteristic of packet delivery offered by most HW and IP. Each packet or datagram is treated as a separate entity containing source and destination addresses. [Comer]
connectionless-oriented communication
Packet transfer in which the delivery is not guaranteed. [CPWW]
connection-oriented protocol/communications.
E.g., SPX, TCP. [Reeves & Reeves]

Guaranteed delivery, a.k.a., reliable. [CPWW]

Circuit switched. [Comer]
connectivity
Linking of nodes on a network in order for communications to take place. [CPWW]
CDDI
Copper Distributed Data Interface
Implementation of FDDI standard using electrical instead of optical cable. [CPWW]
copy backup
Backup of entire HD; similar to full backup except this backup doesn't touch the archive bits on files. [CPWW]

Advantage - one-off B/U doesn't affect schedule.

Disadvantage - time consuming. [p. 586 CPWW]
core gateway
One of a set of routers with explicit routes to all destinations in an internet. It participates in a single routing protocol. Exchanges updates periodically to ensure tables are consistent. [Comer]
core layer
In Hierarchical model, it's the backbone of the network, designed for high-speed data transmission. [CPWW]
crossover cable
Usually a Cat5 cable used to connect two devices, e.g., hubs, or computers without hub or switches. Called such because pins 1 & 3 and 2 & 6 are switched. [Reeves & Reeves]
crosstalk
electronic interference caused when 2 wires get too close to each other. [CPWW]
cut-through packet switching
Switching method which doesn't copy entire packet into switch buffers. Instead, destination address used to determine route to destination node and packet sent out corresponding port. Low latency method. [CPWW]
CRC
cyclical redundancy check
Method used to check for errors in packet that has been transferred across a network. A computation bit is added to the packet and recalculated at the destination to determine if the entire packet contents have been transferred correctly. [CPWW]
D connectors
Connectors using pins and sockets to establish connections between peripherals using serial/parallel ports. The number at end of designation indicates # of pins. [CPWW]
daemon
Service or process running on a Unix server. [CPWW]
data field [in a frame]
In a frame, the field or section that contains the data. [CPWW]
[OSI] data link layer
OSI layer 2 which establishes, maintains, and releases the data connection between 2 elements in a network. [Reeves & Reeves}

Link level communications (e.g., frame formats) or link level connections. Physical frame format & addressing. Ethernet addresses found @ this level. [Comer]

Organizes data into frames, assigns physical addresses, handles error & flow control. [CPWW]
[OSI] Data link layer PDU is?
OSI PDU = frame
DSU
Data Service Unit
Device necessary in transmitting digital data over a HW channel. It converts signals from bridges, routers, and muxes into digital signals. Usually used w/CSU. [Reeves and Reeves]

Formats and controls data for transmission over digital lives. Used w/CSU. [CPWW]
DTE
data terminal equipment
Device used at user end of a user-network interface that serves as a data source or destination or both. These devices include computers, protocol translators, and multiplexors. [CPWW]
Datagram
Information groupings transmitted as a unit at network layer. [CPWW]

Contains source and destination data. [Comer]
DB-9
9 pin connector used for serial-port or parallel-port connection between PC's and peripheral devices. [CPWW]
DB-25
25 pin connector used for serial-port or parallel-port connection between PC's and peripheral devices. [CPWW
dedicated line
Usually used in WANs to provide a constant connection between two points. [CPWW]
Default gateway
Default route for all TCP/IP packets not destined for segment or local subnet. [Reeves & Reeves]
'delete or erase'
Right given to users that allows them to delete a file or files in a directory, or to delete the directory. [CPWW]
destination address
Network address where the frame is being sent. In a packet, this address is encapsulated in a field of the packet so all nodes know where the frame is being sent. [CPWW]
[TCP header field:] destination port
In TCP, port # of application data is being transferred to. 16 bits. [p 236 CPWW]

@+16. [p. 204 Comer]
[UDP header field:] destination port
UDP protocol port # used to demultiplex received datagrams. 16 bits; @+16. [p. 181 Comer]
DSAP
Destination Service Access Point
One byte field in frame which combines w/SAP to inform receiving host of identity of destination host. [CPWW]
device manager
Win95/8 tool that lists all devices in the computer and keeps records of resources and drivers they use. [CPWW]
dialed number identification service
Method for delivering automatic number identification using out-of-band signaling. [CPWW]
dial-up networking
Connection of a remote node to a network using POTS. [CPWW]
differential backup
Backup of only the data that has changed since the previous backup. [CPWW]

Archive bit unchanged.
Advantage - faster than full; restore requires full plus last differential.

Disadvantage - B/U time slower as more time elapses since last full B/U. [p. 586. CPWW]
DAT
Digital Audio Tape
Tape recording technology that uses helical scan method. Used in video tape and video cartridge recorders since 1950's. [CPWW]
DDS
Digital Data Storage
Tape recording technology using helical scan and combines with read-alter-write and error correction technology. [CPWW]
DDS-3
Digital Data Storage 3
State-of-the-art of recording technology. Uses longer tape length and faster speed that previous DDS technology. [CPWW]
DLT
Digital Linear Tape
One of highest performing storage solutions available today. For users needing very large DB backups. [CPWW]
DSL
Digital Subscriber Line
Public network technology delivering high bandwidth over conventional copper at limited distances. [CPWW]
DMA
Direct Memory Access
Transferring data directly into memory at high speed, bypassing CPU and its overhead. [CPWW]
directory services
Organization of the accounts and resources directory to help network devices locate service providers. [CPWW]
disk duplexing
Fault tolerance method where 2nd drive uses own (dupe) controller. [Reeves and Reeves]

RAID 1. [CPWW]
disk mirroring
Fault tolerance method in which the system makes an exact copy of all the data on one drive and write it to a 2nd drive of equal or greater size. Both drives use same controller. [Reeves and Reeves]

RAID 1. [CPWW]
disk striping
Technique used to bind multiple disks together as 1 volume referred to as a stripe set. [CPWW]
distribution layer
In Hierarchical Model, this layer functions as the separation point between the core and access layers of the network. The devices in this layer implement the policies that define how packets are to be distributed to the groups within the network. [CPWW]
domain
Networking system used worldwide on the Internet and in M$ Windows NT networks to identify a controlled network of nodes that are grouped as an administrative unit. [CPWW]
DNS
Domain Name Service/Server
Part of distributed DB system responsible for resolving a FQDN into the 4 part IP # used for routing. [CPWW]
DNS
Domain Name System
Hierarchical client/server based database management system. The DNS was created and is operated by the InterNIC to provide alpha-based names for numeric-based IP addresses. [CPWW]
dot matrix
Printer using several pins to strike an impression upon a form. Useful for multi-part forms. [CPWW]
drive mapping
An alias making a network path appear as if it were a local drive. [CPWW]
Dr. Watson
Debugger that interprets errors in the Windows based applications and creates a log file upon application fault. [CPWW]
dumb terminal
Keyboard/monitor combination that accessed mainframe computers for data but provides no processing at the local level. [CPWW]
DHCP
Dynamic Host Configuration Protocol
Protocol which allows one to dynamically configure TCP/IP nodes and manage them from a central location. It automatically assigns IP addresses and other TCP/IP hosts addresses, e.g., DNS, WINS servers and default gateways. [Reeves and Reeves]
dynamic window
Used in flow control to prevent sender from overwhelming receiver. [CPWW]
EMI
electromagnetic interference
Term used for external interference of electromagnetic signals that causes reduction of data integrity and increased error rates in a transmission medium. [CPWW]
electrophotography
Photocopy process technology used by laser printers and copy machines. [CPWW]
ERD
Emergency Repair Disk
Floppy disk containing security files and resource configurations used for recovery when a M$ Win NT operating system becomes corrupt. [CPWW]
encapsulation
Process used to send data across a network where the network doesn't recognize protocol. Network doesn't decode it. [Reeves and Reeves]

Technique used by layered protocols in which a layer adds header information to the PDU from the later above. [CPWW]
encryption
Modification of data for security purposes prior to transmission so that it is not comprehensible without the decoding method. [CPWW]
Ethernet
A shared-media network architecture. Operates at OSI physical and data link layers. Uses bus topology, <_ 10 Mbps [sic], CSMA/CD. [Reeves and Reeves]

A best effort delivery system. [Comer]
event viewer
Troubleshooting tool in NT WS/Server. It provides 3 logs that record system information: System log, security log, application log. [CPWW]
EISA
Extended Industry Standard Architecture
Successor to ISA standard. 32-bit bus interface used in PCs. [CPWW}

Max speed 8.25 MHz; capacity 33 MB/second. [p. 170 CPWW]
Fast Ethernet
802.3 spec <_ 100 Mbps
FAST SCSI
SCSI-2 @ 10 Mbps. [CPWW]
Fast-20 SCSI
SCSI-3 w/MegaTransfer rate = 20 Mbps, a.k.a, Ultra SCSI. [CPWW]

<_3 m. [CPWW]

8 bit bus; <_ 7 devices; [p. 489 CPWW]
Fast-40 SCSI
SCSI-3 w/MegaTransfer rater of 40 Mbps. Cable length <- 12 m., a.k.a., Ultra-2 SCSI. [CPWW]

8 bit; <_ 7 devices. [p. 490 CPWW]
Fast-wide SCSI
Fast SCSI over a 2 byte (wide SCSI) parallel path.
FW SCSI-20 @ 40 Mbps. = Ultra wide
FW SCSI-40 @ 80 Mbps. = Ultra-2 wide
[CPWW]

<_15 devices. [p. 490 CPWW]
fault tolerance
Theoretical concept defined as a resistance to failure. It isn't absolute but relative. [CPWW]
fiber channel
Technology defining full Gigabit/second data transfer over fiber-optic cable. [CPWW]
FDDI
Fiber Distributed Data Interface.
High speed data-transfer technology designed to extend capabilities of existing LANs using a dual rotating ring technology similar to token-ring. [CPWW]
fiber-optic cable
Physical medium capable of conducting modulated light transmissions. More expensive than other transmission media but not susceptible to EMI and capable of higher data rates. [CPWW]
file rights
Method of granting access to a file or directory. [CPWW]
FTP
File transfer protocol
Set of standards or protocols that allow transfer of complete files between different computer hosts. [CPWW]
flow control
Method used to control amount of data transmitted within given time period. [CPWW]

Usually to avoid congestion. [Comer]
fragment-free
Fast packet-switching method using 1st 64 bytes of frame to detect corruption. If intact, the frame is forwarded. [CPWW]
frame
Grouping of information transmitted @ Data Link Layer. [CPWW]

Packet as it is transmitted across serial line. [Comer]
Frame Check Sequence Field
Field used for CRC to insure frame integrity. [CPWW]
Frame Length Field
Field in a data frame specifying length. For 802.3 <_ 1518 bytes. [CPWW]
frame relay
Data link layer switching protocol used across multiple virtual circuits of a common carrier, giving the end user the appearance of a dedicated line. [CPWW]
frame type field
In a data frame, the field that names the protocol that is being sent in the frame. [CPWW]
FDM
Frequency Division Multiplexing
Division of O/P channel into multiple smaller bandwidth channels, each using a different frequency range. [CPWW]
full backup
Backup method in which every file on the HD is copied. [CPWW]

Archive bit cleared on all files.

Advantage - Restore needs only 1 tape.

Disadvantage - Time consuming. [p.586 CPWW]
full-duplex
Transmission of data in two directions simultaneously. [CPWW]
FQDN
Fully qualified domain name.
Complete name for a machine on a network. Hostname + domain name. [Reeves & Reeves].
gateway
HW and SW solution enabling communication between 2 dissimilar NOS's or protocols. They usually operate @ upper layers of the OSI protocol stack above the Transport Layer. [CPWW]
[TCP FTP} GET command
Download a file from a TCP FTP server. [p. 349 CPWW]
Gigabit Ethernet
IEEE spec for transfer rates <_ 10**3 Mbps. [CPWW]
GFS
Grandfather-Father-Son
Backup strategy of maintaining backups on a daily, weekly, and monthly schedule. Full backups performed >_ once per week. All others are full, incremental, or differential or nonexistent. Daily incremental or differential is the son. Last full backup in week is the father. Last full backup of month is the Grandfather. [CPWW]
group object
Collection of user accounts represented by a single label. [CPWW]
guaranteed flow control
Sending and receiving host agree upon a rate of data transmission. Afterwards, communications will take place @ that rate until sender finished. No buffering @ receiver. [CPWW]
half-duplex
Circuit designed for data transmission in both directions, but not simultaneously. [CPWW]
handshaking
Initial communication between 2 modems, during which they agree upon protocol and transfer rules for the session. [CPWW]
Helical scan method
Extremely high-density recording method on a relatively slow moving tape. It enters in an angular manner that allows reads and writes diagonally across the tape rather than just straight across. [CPWW]
HSSI
High Speed Serial Interface
Standard for high speed serial over WAN links. It includes frame relay, T1, T3, E1, and ISDN. [CPWW]
HKEY_CLASSES_ROOT
Windows registry key containing file associations & OLE data that made up Win 3.x registration DB. [CPWW]
HKEY_CURRENT_CONFIG
Win registry key containing info about HW that PC had @ original bootup. [CPWW]
HKEY_CURRENT_USER
Windows registry key containing settings & preferences of users currently logged on. [CPWW]
HKEY_DYN_DATA
Window registry key containing PnP information and information about current PC state. [CPWW]
HKEY_LOCAL_MACHINE
Win registry key containing data about PC HW & installed SW (type of data formerly stored in Win 3.x system.ini). [CPWW]
HKEY_USERS
Windows registry key containing user settings and preferences, including color schemes, desktop settings, mapped network drives (formerly found in Windows 3.x win.ini). [CPWW]
[TCP header field;] HLEN or data offset
In TCP/IP header it shows the point in the packet where data starts. 4 bits. [p. 264 CPWW]

@+96. Value expressed in 32 bit multiples. [p. 204 Comer]
host
Used generically for any system on a network. In Unix world, used for any device assigned an IP address. [CPWW]
host ID
Identifier used to uniquely identify a client or resource on a network. [CPWW]
hostname (NetBIOS)
Name of IBM PC or of node, given to 1st element of Internet domain name. Must be unique within local network. [CPWW]
HOSTS file
Used for TCP/IP resolution of domain names. [CPWW]

Most commonly used for TCP/IP hostname/domain name to IP address resolution. [p. 328 CPWW]
hub
Device normally @ center of star topology net. Other devices in net connect to it. They're essentially repeaters. [Reeves & Reeves]

A.k.a. concentrator or multiport repeater. A HW device connecting multiple independent nodes. [CPWW}

Usually uses twisted pair. [Comer]
HyperTerminal
Communication program that allows you to establish host/shell access to a remote system. [CPWW]
HTTP
Hypertext Transfer Protocol
Protocol used by web browsers to transfer pages and files from the remote node to your computer. [CPWW]
IEEE 802.1
Overview of project 802 including internetworking. Standard defining OSI physical and data link layers. Allows 2 IEEE LAN stations to communicate over a LAN or WAN. A.k.a. "internetworking standard". Includes spanning tree algorithm spec. [CPWW]
IEEE 802.2
LLC. Standard defining LLC sub-layer for entire series of protocols covered by 802.x standards. It specifies the adding of header fields, which tell the receiving host which upper layer sent the info. Defines LLC implementation specs. Commonly used with 802.3, -4, -5. [CPWW]
IEEE 802.3
For bus networks using CSMA/CD, e.g., Ethernet. Standard specifying physical layer attributes, e.g., signaling types, data rates and topologies, and media access method used. Physical layer and MAC implementation specs using CSMA/CD. Also includes original Fast Ethernet specs. [CPWW]
IEEE 802.4
Token bus. Standard defining how production machines should communicate and their protocol. Also specs for implementation of physical layer and MAC sub-layer of data link layer using TR access over bus topology. Commonly used in factories not corporate LANs. [CPWW]
IEEE 802.5
Token ring (pieces thereof). Specifications for implementation of physical layer and MAC sub-layer of data link layer using a token-passing media-access method over a ring topology. [CPWW]
IEEE 802.6
MAN. Standard defining distributed queue dual bus (DQDB) technology to transfer high speed data between nodes. Also provides specs for MAN implementation. [CPWW]
IEEE 802.7
Broadband. Standard that defines design, installation, and testing of broadband based communications and related physical media connectivity. [CPWW]
IEEE 802.8
Standard defining a group of people who advise the other 802-standard committees on various fiber-optic technologies and standards. Called Fiber Optic Technical Advisory Group. [CPWW]
IEEE 802.9
Voice/data integration over LAN or ISLAN. Standard that defines the integration of voice and data using isochronous Ethernet (IsoEnet). [CPWW]
IEEE 802.10
Interoperable LAN security. Standard that focuses on security issues by defining standard method for protocols and services to exchange data securely using encryption. Can apply to any of 802 standards. [CPWW]
IEEE 802.11
Wireless. Standard that defines implementation of wireless technologies, e.g., infrared spectrum radio. [CPWW]
IEEE 802.12
Standard defining 100BaseVG-AnyLAN which uses a 1,000M BPS signaling rate and a special media-access method allowing 100Mbps data traffic over voice-grade cable. [CPWW]
implied access
Term referring to rights inherited from an upper level directory. [CPWW]
incremental backup
A backup of only those files that have changed since the last backup. [CPWW]

Archive bit - cleared on files baked up of any type.

Advantage - fast

Disadvantage - Restore requires full plus all previous incrementals. [p. 586 CPWW]
ISA
Industry Standards Architecture
8-bit and 16-bit bus and card architecture for PC. [CPWW]

Max speed 8.25 MHz; capacity 16.5 MB/second. [p. 170 CPWW]
ink jet
Printer technology that splashes/ejects ink onto paper. [CPWW]
I/O
input/output
Any operation in which data is either entered into a computer or taken out of a computer. [CPWW]
IDE
Integrated Disk Electronics
Common type of PC disk drives with controller integrated into device. [CPWW]
ISDN
Integrated Services Digital Network
International standard for end-to-end digital communication over PSTN permitting carrying data, voice, and other source traffic. [?]
intelligent hubs
Hubs containing some management or monitoring capability. [CPWW]
interface
Device such as a card or plug that connects pieces of HW with the computer so that information can be moved from place to place. [CPWW]
IDF
Intermediate Distribution Facility
Intermediate location for routing network cabling in a building. Connected to users at one end and main one at other end. [Reeves & Reeves]
internal IPX address
Unique eight digit number that is used to idenfity a server. Generally generated at random when the server is installed. [CPWW]
internal loopback address
Used for testing with TCP/IP. This address - 127.0.0.1- allows a test packet to reflect back into the sending adapter to determine if it is functioning properly. [CPWW]
ICMP
Internet Control Message Protocol
Network-layer Internet protocol (RFC792) that reports errors and provides other information relevant to IP packet processing. [CPWW]
Internet domain name
Computer name + top-level domain of machine + root-level domain. In the Internet. [CPWW]
IGMP
Internet Group Management Protocol
Protocol which manages and reports IP multicast group memberships. [CPWW]

Keeps local routers apprised of membership in multicast groups. [Comer]
[M$] IIS
Internet Information Server
Win NT web server component. [Reeves & Reeves]
[TCP/IP] Internet Layer
In TCP/IP model, layer for addressing, packaging, and routing functions. Protocols of this layer encapsulate packets into Internet datagrams. All necessary routing algorithms run here. [CPWW)

OSI Network layer. [p. 115 CPWW]
IP
Internet Protocol
2 parts,
Network layer protocol (RFC 791) offering connectionless internetwork service. It provides features for addressing, packet fragmentation and reassembly, type-of-service specs, and security. [CPWW]

Defines datagram as unit of information. It's a best effort delivery service. [Comer]
internetwork
Group of networks that are connected by routers or other connectivity devices so that the networks function as one network [CPWW]
IPX
Internetwork Packet Exchange
Protocol based on XNS protocol. Connectionless. Provides datagram services. Used in Netware 3.x and 4.x. [Reeves & Reeves].

Packet size <_ 64K. [CPWW]
IPX/SPX
Internetwork Packet Exchange/Sequenced Packet Exchange
Default protocol used in NetWare networks. It is a combination of the IPX protocol to provide addressing and SPX to provide guaranteed delivery for IPX. Similar in nature to its counterpart, TCP/IP. [CPWW]
IRQ
Interrupt Request
Number assigned to a computer device. Used to determine priority and path in communications between device and CPU. [CPWW]
IPCONFIG
Win NT command displaying TCP/IP settings. [Reeves & Reeves]

Including IP address. [CPWW]
IPSec
Protocol for VPNs. Provides strong security standards for encryption and authentication. [CPWW]
isochronous transmission
Method of async transmission requiring a node other than the sender/receiver to provide clocking. [CPWW]
jumpered or jumpering
Refers to the physical placement of shorting connectors on a board or card. [CPWW]
K56flex technology
One of the original two 56Kbps data-transfer technologies designed for modems. They were both replaced by the V.90 standard. [CPWW]
Kermit
Commonly used terminal-emulation and file-transfer program. [CPWW]
laser printer
Type of printer that uses electrophotography. [CPWW]

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