Term
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Definition
Model developed by ISO for the purpose compatibility.
Layers
Application
Presentation
Session
Transport
Network
Data Link
Physical |
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Definition
Layer 7
Provides services and utilities enabling applications and programs to access network resources. Only layer user directly interacts with.
E-mail (SMTP, POP, IMAP)
File Transfer(FTP, TFTP)
Saving Data to Server
Web Access(HTTP, DNS)
Other Protocols: NFS (Translator between OSs, basically), NTP (Network Time Protocol), Telnet |
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Definition
Layer 6
Encodes data into network-compatible format (ensures both ends are speaking same language). Encryption, Decryption and compression.
Only intermediary, will change at lower layers.
SSL, TLS, GIF, JPEG, TIFF |
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Definition
Layer 5
Establishes and maintains connections, terminates and restarts when required. Synchronizes data transfer. |
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Layer 4
Accepts data from upper layers, divides it into segments, passes segments to lower layer, and ensures safe and correct arrival at receiving end (if using TCP). Carries out error correction.
Gateways can operate at this and higher layers.
TCP, UDP, IPSec, |
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Definition
Layer 3
Protcol Data Unit - IP Packet added to Segment (can now travel across routers since it has IPs). Routers and broadcast domains operate here. Layer 3 switches exist.
IP, ARP, ICMP (Internet Control Message Protocol), DHCP, RIP (Routing Information Protocol) |
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Layer 2
Involves all local network communications. MAC address comes into play here. Swtiches and bridges operate here.
Puts packets into frames (Frame contains MAC addresses and Frame Check Sequence) |
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Term
| Data Link Sublayers - Logical Link Control |
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Definition
| Responsible for indentifying Network layer protocols, and tells the the Data Link layer what to do with a frame when it is received (pass it up to network or discard). |
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Term
| Data Link Sublayers - MAC |
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Definition
| Responsible for defining how packets are placed on the transfer media. Carrier sense and token passing ar its responsibilities. Bridges and switches. |
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Definition
Layer 1
Provides means of transmitting over physical medium. Sends and receives bits (1's and 0's, electrical signals).
Wires, other physical mediums (NOT NICS!) |
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Layer 2
LAN technology that uses Ethernet NICs and twisted pair, coaxial, or fiber cables |
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Definition
| Uses switches to allow for full duplex communication (full bandwith of medium) |
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Term
| Ethernet Frame Fields - Preamble |
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Definition
| Binary pattern that signals start of a frame and synchronizes timing. 8 bytes |
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Term
| Ethernet Frame Fields - Destination and Source Address |
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Definition
Contains the MAC address the frame is being sent to as well as the origin MAC address. The destination MAC can be uni, multi or broadcast. The source is unicast.
12 bytes total (both addresses) |
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Term
| Ethernet Field Frames - Frame Type |
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Definition
| Tells which upper layer protocol should receive the data after it is processed. 2 bytes |
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Term
| Ethernet Frame Field - Data |
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Definition
| The data itself, the whole reason for the frame's existence. Maximum of 1500 bytes. |
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Term
| Ethernet Frame Field - FCS or CRC |
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Definition
Frame Check Sequence or Cyclical Redundancy Check
Checks the quality and integrity of recieved data.
4 bytes |
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Definition
The original Ethernet standard, originally developed by Xerox in the 1970's, adopted by IEEE in the 1980's. Specifies media type, speed and signal method
Ex. 10BaseT |
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| The Layer 2 (Data Link) sublayers LLC and MAC |
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Definition
IEEE 802.3a
Thinnet coax
185 meters |
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Term
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Definition
IEEE 802.3
Thicknet coax
500 meters |
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Term
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Definition
IEEE 802.3i
Category 5 UTP
100 meters |
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Term
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Definition
IEE 802.3j
Fiber
2000 meters |
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Term
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Definition
IEEE 802.3j
Fiber
2000 meters |
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Term
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Definition
IEEE 802.3j
Fiber
2000 meters |
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Term
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Definition
IEEE 802.3j
Fiber
500 meters |
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Term
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Definition
IEEE 802.3u
Cat5 UTP
100 meters |
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Term
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Definition
IEEE 802.3u
Cat 3, 4 or 5 UTP
100 meters |
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Term
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Definition
IEEE 802.3u
Cat 5 UTP
100 meters |
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Term
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Definition
IEEE 802.3u
Multimode Fiber
412 meters for half duplex
2000 meters full duplex |
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Term
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Definition
IEEE 802.3u
Single mode fiber
15,000 to 20,000 meters for full duplex |
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Term
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Definition
IEEE 802.3ab
Cat 5 or 6 UTP
100 meters |
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Term
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Definition
IEEE 802.3z
Shielded, balanced coax
25 meters
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Term
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Definition
IEEE 802.3z
Multimode fiber, 850nm NIR wavelength
550 meters in practice (220 meters spec) |
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Definition
IEEE 802.3z
Single mode = 1300nm wavelength, 5000 meters
Multimode = 1300nm wavelength, 550 meters |
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Term
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Definition
IEEE 802.3z
Single mode = 1300 nm wavelength, 10,000 meters
Multimode = 1300 nm wavelength, 550 meters |
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Definition
IEEE 802.3ae
Multimode, 850 nm wavelength
9.953 Gbps
65 meters |
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Term
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Definition
IEEE 802.3ae
Multimode
850 nm wavelength
10.31 Gbps
300 meters |
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Term
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Definition
IEEE 802.3ae
Multimode
850 nm wavelength
9.953 Gbps
300 meters |
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Term
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Definition
IEEE 802.3ae
Single mode
1310 nm wavelength
Dark fiber (?)
10.31 Gbps
10,000 meters |
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Term
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Definition
IEEE 802.3ae
Single mode
1310 nm wavelength
SONET
9.593
10,000 meters |
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Term
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Definition
IEEE 802.3ae
Single mode
1550 nm wavelength
Dark fiber
10.31 Gbps
40,000 meters
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Term
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Definition
IEEE 802.3ae
Single mode
1550 nm wavelength
SONET
9.593 Gbps
40,000 meters
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Term
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Definition
IEEE 802.3an
Cat 5, 6 or 7 UTP
10 Gbps
100 meters
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Term
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Definition
IEEE 802.3ak
Thin twin-axial cables
4 x 2.5 Gbps
25 meters |
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Term
| Fiber Wavelength Varieties - 1000BaseLX |
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Definition
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Term
| Fiber Wavelength Varieties - 100BaseSX |
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Definition
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Term
| Fiber Wavelength Varieties - 10GBaseSR |
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Definition
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Term
| Fiber Wavelength Varieties - 10GBaseLR |
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Definition
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Term
| Fiber Wavelength Varieties - 10GBaseER |
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Definition
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Term
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Definition
Computers pass a bit sequence (called a token) between them. The computer holding the token can transmit on the network. After transmitting, or if it has nothing to transmit in the first place, the token is passed to the next node.
Standards dictate how long a node can hold the token and what happens if it is damaged or lost. |
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Term
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Definition
Multi Station Access Unit
All machines in a Token Ring connect to one. Also used to connect multiple rings, creating a larger ring. |
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Term
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Definition
Fiber Distributed Data Interface
Uses dual rings of multi or single mode fiber cables (one ring for control signals, one for data transmission) for redundancy purposes. The control signal ring can be used for data tranmission, doubling the capacity to 200 Mbps. |
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Definition
| Radiate radio frequency waves in a 360 degree pattern or horizontal plane |
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Definition
| Concentrates signals into a cone called a beam. Point to point, long range |
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Term
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Definition
| Narrow beam, point to point. Long range. Grid array more reliable in windy conditions than parabolic dish. |
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Definition
| Family of specifications for wireless communication. Uses CSMA/CA, FHSS and DSSS |
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Term
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Definition
| Two varaiations: Both are 1 to 2 Mbps, one is FHSS, other is DSSS |
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Term
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Definition
| 54 Mbps, 2.4GHz. Typically transfers at 6, 12 or 24 Mbps |
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Term
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Definition
| 11 Mbps, 2.4GHz. 100 meters |
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Term
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Definition
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Term
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Definition
| Utilizes one or more WAPs to connect workstations to the cable backbone. Use BSS or ESS |
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Term
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Definition
| Peer to peer (wireless workstation connects to another wireless workstation) |
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Term
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Definition
| One access point connected to a wired network and has one or more wireless stations or clients. No direct, client-to-client connections. |
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Term
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Definition
| Two or more BSSs that are connected through a common distribution system (wired network). Allows mobility and data to be forwarded between BSSs over the backbone. |
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Term
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Definition
| Name that identifies a wireless access point or network. |
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Term
| Independent Basic Service Set |
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Definition
| No access point, just peer-to-peer. All stations transmit and receive. |
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Term
| 802.11 Beacons (Beacon Frames) |
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Definition
| Fifty-byte frames used to start and maintain wireless communcations. Contain STA SSID, channel number, security protocol information. |
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Term
| Wired Equivalency Privacy |
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Definition
Defines an algorithm giving all authorized users security equivalent to a wired network (lolz). Passphrase is used to generate the key. 64 -bit and 128-bit options. (40)
Very easily cracked, so it isn't that great. |
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Term
| Wi-fi Protected Access (WPA and WPA2) |
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Definition
Designed to improve the flaws of WEP. Improved the data encryption using TKIP (Temporal Key Integrity Protection). Generates a new (dynamic) key each time one connects. Also has integrity checking.
WPA2 uses EAP (Extensible Authentication Protocol), which makes use of a publically-shared key encryption system. |
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Term
| Auth. Methods - Open System |
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Definition
| Default for most access points. The AP is wide open, no authentication required. |
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Term
| Auth. Methods - Shared Key |
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Definition
| Verifies identity of STA by using WEP. Both the station and AP must be configured with same WEP key. |
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Term
| Auth. Methods - 802.1x and EAP |
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Definition
| Authenticates user, not the station by using a third party. The third party is often a RADIUS (Remote Authentication Dial-In User Server) server, which the AP forwards authentication requests to. The RADIUS calls the user ceredential database for verification. The RADIUS server then sends the verifications notice to the AP. |
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Term
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Definition
Wireless protocol used to communicate between two wireless devices in a small area (less than 30 feet) using RF. Uses 2.4 GHz spectrum and a 1 Mbps connection (232 Kbps voice channel and 768 Kbps data channel).
Bluetooth 2.0 data rate is 2.1 - 3 Mbps, and can go as far as 30 meters (100 feet).
NOTE: WPAN |
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