Acronym |
Meaning |
Primary Applicability |
Normative Reference |
ACK |
Acknowledgement |
Transport and
other layers |
TCP/IP, for
example. RFC 793 |
ACL |
Access
control list |
Security,
application layer |
Access
control list, Cisco overview |
ADSL |
Asymmetric
digital subscriber line |
Telecom |
ITU-T G.992.5
Annex M, for example |
AES |
Advanced
Encryption Standard |
Security |
U.S. FIPS PUB
197 |
ANSI |
American
National Standards Institute |
Organization |
ANSI |
ARP |
Address
Resolution Protocol |
Link layer |
RFC 1122 |
ATM |
Asynchronous
Transfer Mode |
Telecom |
ATM cell
description |
BGP |
Border
Gateway Protocol (routing protocol) |
Application
layer, Routers |
RFC 4271 |
BSS |
Basic service
set (Wi-Fi) |
Wireless |
IEEE Std 802.11-2007 |
CAT |
Category
(e.g. CAT-5 cable) |
Physical
layer |
ANSI/TIA/EIA-568-B.1-2001 |
CCITT (obs.) |
Standards
organization that has been replaced by ITU-T |
Organization |
ITU-T |
CHAP |
Challenge-Handshake
Authentication Protocol (PPP) |
Security,
telecom |
RFC 1994 |
CIDR |
Classless
Inter-Domain Routing |
Architecture |
RFC 1518 RFC
1519 |
CIR |
Committed
Information Rate (Frame Relay) |
Telecom |
RFC 1490 RFC
1973 RFC 2427 |
CLI |
Command line
interpreter |
Hardware |
Catalyst 6500
Series Command Reference, 7.6, for example |
CPE |
Customer
premises equipment |
Telecom |
Telecom
Glossary |
CRC |
Cyclical
redundancy check |
Link and
other layers |
24 References
here. |
CRC-16-CCITT |
Cyclical
redundancy check (X.25, HDLC) |
Link layers |
Reference on
CRC page. |
CSMA/CA |
Carrier sense
multiple access / collision avoidance |
Wireless |
IEEE Std 802.11 Downloads |
CSMA/CD |
Carrier sense
multiple access / collision detection |
Physical
layer |
IEEE Std 802.3TM-2002 |
CSU/DSU |
Channel
service unit / data service unit |
Telecom |
Telecom
Glossary |
DCE |
Data
communications equipment |
Telecom |
Telecom
Glossary |
DEC (obs.) |
Digital
Equipment Corporation |
Organization |
Purchased by
Compaq in 1998. Merged with Hewlett-Packard 2002. |
DES |
Data
Encryption Standard (obs. See AES) |
Security |
Federal
Information Processing Standard (FIPS) FIPS-46-3 |
DHCP |
Dynamic Host
Configuration Protocol |
Application
layer, Internet Layer |
RFC 2131 and
others |
DNS |
Domain Name
System |
Application
layer |
Over 30 RFCs
here. |
DRAM |
Dynamic
random-access memory |
Hardware |
|
DSL |
Digital
Subscriber Line |
Telecom |
Telecom
Glossary |
DSLAM |
Digital
Subscriber Line Access Muliplexor |
Telecom |
Telecom
Glossary (proposed) |
DTE |
Data Terminal
Equipment |
Telecom |
Telecom
Glossary |
EHA |
Ethernet
Hardware Address (MAC address) |
Link layer |
IEEE Std 802 IEEE OUI Assignments |
EIA |
Electronics
Industry Alliance |
Organization |
EIA |
EIGRP |
Enhanced
Interior Gateway Routing Protocol |
Internet
Layer |
Cisco Doc ID:
16406 |
EOF |
End Of Frame
(HDLC, etc.) |
Link layer |
HDLC framing |
ESS |
Extended
service set (Wi-Fi group) |
Wireless |
IEEE Std 802.11-2007 |
FCC |
Federal
Communications Commission (US) |
Organization |
US FCC |
FCS |
Frame check
sequence (Ethernet) |
Link layer |
Ethernet
Frame IEEE Std 802.3 |
FDDI |
Fiber Distributed Data Interface |
Link layer |
American
National Standards Institute X3T9.5 (now X3T12), ISO/IEC 9314-x |
FTP |
File Transfer
Protocol |
Application
layer |
RFC 959 and
others |
GBIC |
Gigabit
interface converter |
Hardware |
Seagate
Specification |
Gbps |
Gigabit per
second |
Physical
layer |
Gigabit per
second |
HDLC |
High-level
Data Link Control |
Link layer |
ISO 13239 |
http |
HyperText Transfer Protocol |
Application
layer |
W3C Change
History for HTTP |
https |
HyperText Transfer Protocol Secure |
Transport and
other layers |
SSL 3.0
Specification |
IANA |
Internet
Assigned Number Authority |
Organization |
IANA |
ICMP |
Internet
Control Message Protocol |
Internet
Layer |
RFC 792 |
IDF |
Intermediate
distribution frame |
Physical
layer |
Structured
cabling or Telecom Glossary |
IDS |
Intrusion
Detection System |
Security |
Cisco Product
Index |
IEC |
Commission Electrotechnique Internationale (French) |
Organization |
IEC |
IEEE |
Institute for
Electrical and Electronic Engineers |
Organization |
IEEE |
IETF |
Internet
Engineering Task Force |
Organization |
IETF |
IMAP |
Internet
Message Access Protocol |
Application
layer |
RFC 3501 |
IP |
Internet
Protocol |
Internet
Layer |
RFC 791 RFC
1606 |
IPS |
Intrusion
prevention system |
Security |
ÒNIST –
Guide to Intrusion Detection and Prevention Systems (IDPS)Ó. 2007-02.
Retrieved 2010-08-24. |
IS-IS |
Intermediate
System to Intermediate System (routing protocol) |
Internet
Layer |
ISO/IEC
10589:2002 |
ISDN |
Integrated
Services Digital Network |
Telecom |
IEC Area
716-xx |
ISP |
Internet
service provider |
Telecom |
Telecom
Glossary |
ITU-T |
International
Telecommunications Union |
Organization |
http://www.itu.int |
kbps |
Kilobit per
second |
Physical
layer |
Kilobit_per_second |
LAN |
Local area
network |
Link and
other layers |
Telecom
Glossary |
LAPB |
Link Access
Procedure, Balanced (x.25) |
Telecom |
ITU-T
Recommendation X.222 |
LAPF |
Link-access
procedure for frame relay |
Telecom |
RFC 1490 |
LLC |
Logical link
control |
Link layer |
Telecom
Glossary |
MAC |
Media access
control |
Link layer |
IEEE Std 802.3 and 802.11, for example |
MAN |
Metropolitan
area network |
Telecom |
Telecom
Glossary |
Mbps |
Megabits per
second |
Physical
layer |
Megabit_per_second |
MC |
Multiple
choice |
IT
Professional Certification |
About
certification exams |
MDF |
Main
distribution frame |
Physical
layer |
Glossary See
also Structured cabling |
MIB |
Management
information base (SNMP) |
Application
layer |
RFC 3418 |
MPLS |
Multiprotocol
Label Switching |
network
technology |
|
MTU |
Maximum
Transmission Unit |
Multiple
layers |
|
NAC |
Network
access control |
Link and
other layers |
IEEE 802.1x |
NAT |
Network
Address Translation |
Internet
Layer |
Cisco
Internet Protocol Journal: A look Inside Network Address Translators |
NBMA |
Non-Broadcast
Multiple Access (e.g. Frame Relay ATM) |
Telecom |
See ATM,
Frame Relay and X.25, for examples. |
NIC |
Network
Interface Card |
Physical
layer |
Telecom
Glossary |
NRZ |
Non-return-to-zero |
Physical
layer |
Federal
Standard 1037C |
NRZI |
Non-return to
zero inverted |
Physical
layer |
Federal
Standard 1037C |
NVRAM |
Non-volatile
RAM |
Hardware |
Sample vendor
data here |
OSI |
Open System
Interconnect (joint ISO and ITU standard) |
Organization |
ISO/IEC
9594-5:2005 Open Systems Interconnection Protocol Specifications |
OSPF |
Open Shortest
Path First (routing protocol) |
Internet
Layer |
RFC 2238 |
OUI |
Organization
Unique Identifier |
Link and
other layers |
IEEE OUI
Assignments |
PAP |
Password
authentication protocol |
Security |
RFC 1334 |
PAT |
Port address
translation |
Internet
Layer |
RFC 1918 |
PC |
Personal
computer (host) |
Hardware |
|
PIM |
Personal
information manager |
Software
category |
|
PCM |
Pulse-code
modulation |
Physical
layer |
ITU-T G.711 |
PDU |
Protocol data
unit (such as segment, packet, frame, etc.) |
Multiple
layers |
Fed Std 1037C |
POP3 |
Post Office
Protocol, version 3 |
Application
layer |
RFC 1939 |
POP |
Point of
presence |
Telecom |
Telecom
Glossary |
POST |
Power-on self
test |
Hardware |
Cisco
Catalyst 2800 User Guide, for example |
POTS |
Plain old
telephone service |
Telecom |
Telecom
Glossary |
PPP |
Point-to-point
Protocol |
Telecom |
RFC 1661 |
PPTP |
Point-to-Point
Tunneling Protocol |
Telecom |
RFC 2637 |
PTT |
Public
Telephone and Telegraph |
Telecom |
Telecom
Glossary or Free Dictionary |
PVST |
Per-VLAN
Spanning Tree |
Link layer |
CiscoÕs
introduction to Spanning Tree Protocol |
RADIUS |
Remote
Authentication Dial-In User Service |
Security |
RFC 2865 |
RAM |
Random Access
Memory |
Physical
layer |
Telecom
Glossary |
RARP |
Reverse ARP |
Link layer |
RFC 903 |
RFC |
Request for
Comments |
Multiple
layers |
IETFÕs RFC
Index |
RIP |
Routing
Information Protocol |
Internet
Layer |
RFC 2453, for
RIP version 2 |
RLL |
Run-Length
Limited |
Physical
layer |
RLL is used
in a wide range of encodings. |
ROM |
Read-Only
Memory |
Hardware |
Telecom
Glossary |
RSTP |
Rapid
Spanning Tree Protocol |
Link layer |
IEEE 802.1w
– Rapid Reconfiguration of Spanning Tree |
RTP |
Real-time
Transport Protocol |
Application
layer |
RFC 3550 |
SDLC |
Synchronous
Data Link Control |
Link layer |
Cisco
Technology Handbook: SDLC and Derivatives |
SFD |
Start-of-frame
delimiter (Ethernet, HDLC, etc.) |
Link layer |
IEEE 802.3
(Ethernet), or RFC 2687 (HDLC), for examples |
SFP |
Small
form-factor pluggable |
Hardware |
Seagate
Specification |
S-HTTP |
Secure HTTP
(rarely used) |
Transport and
other layers |
RFC 2660 See
also https |
SLARP |
Serial Line
ARP (Address Resolution Protocol) |
Link and
other layers |
Archived
Cisco Serial Line Encapulation extension |
SLIP |
Serial Line
Internet Protocol (obs.) |
Telecom |
RFC 1055 |
SMTP |
Simple Mail
Transfer Protocol |
Application
layer |
RFC 5321 |
SNA |
Systems
Network Architecture (IBM) |
Multiple
layers |
SNA Protocol
Suite |
SNAP |
SubNet Access Protocol |
Link layer |
IEEE 802
Overview and Architecture |
SNMP |
Simple
Network Management Protocol |
Application
layer |
RFC 1155, RFC
3410 thru RFC 3418 and others |
SOF |
Start of
frame |
Link layer |
IEEE 802.3
(Ethernet), or RFC 2687 (HDLC), for examples |
SRAM |
Static random
access memory |
Hardware |
PC GuideÕs
Definition |
SSH |
Secure shell |
Application
layer |
RFC 4252 |
SSID |
Service set
identifier (Wi-Fi) |
Wireless |
IEEE 802.11 |
STP |
Spanning Tree
Protocol |
Link layer |
CiscoÕs
Introduction to Spanning Tree Protocol |
SYN (TCP) |
Synchronization |
Link and
other layers |
RFC 793 and
many others |
TCP/IP |
Transmission
Control Protocol/Internet Protocol |
Transport
layer |
RFC 793 and
many others |
TDM |
Time-division
multiplexing |
Physical
layer |
Fed Std 1037C |
TFTP |
Trivial File
Transfer Protocol |
Application
layer |
RFC 1350 |
TIA |
Telecommunications
Industry Alliance |
Organization |
Telecommunications
Industry Association |
UDP |
User Datagram
Protocol |
Transport
layer |
RFC 768 |
USB |
Universal
Serial Bus |
Physical and
other layers |
USB 3.0
Specification |
UTP |
Unshielded
twisted pair |
Physical |
Many versions
are defined by TIA, such as: TIA-568-B |
VC |
Virtual
circuit |
Transport and
other layers |
Telecom
Glossary |
VLAN |
Virtual local
area network |
Link layer |
IEEE 802.1Q |
VLSM |
Variable-length
subnet masking |
Architecture |
RFC 1518 RFC
1519 |
VPN |
Virtual
private network |
Application
layer |
Virtual
Private Network Consortium |
W3C |
World Wide
Web Consortium |
Organization |
W3C |
WAN |
Wide-area
network |
Telecom |
Telecom
Glossary |
WEP |
Wired
Equivalent Privacy |
Wireless |
IEEE 802.11 |
Wi-Fi |
IEEE 802.11
(Wi-Fi Alliance) |
Wireless |
Wi-Fi
Alliance |
WPA |
Wi-Fi
Protected Access |
Security |
IEEE 802.11i |
www |
World Wide
Web |
Architecture |
W3C
Consortium |