Network Implementations 4 Flashcards
What is switched Ethernet
A LAN technology that connects computers using switches. Enables the device to utilize the full bandwidth of the medium. Switches recognize the destination address and route the packet only to the destination node. Can route multiple packets to different destinations simultaneously
What is Ethernet
Specific for LAN.
Allows computers to communicate over small distances using twisted pair cables in the subnetworks and optical fibers or coaxial cables in the network backbone. IEEE standard 802.3
An Ethernet frame is
A data packet that has been encoded in the data link layer for transmission from one node to another on an ethernet network.
Name the seven Ethernet frame fields
Preamble PRE. 7 bytes notified all nodes data is to follow
Start-of-frame delimiter SFD. 1byte identified the beginning of the data field
Destination address DA. 6 bytes MAC address of target computer
source address SA. 6 bytes MAC Address of computer that is sending transmission
Frame type. 2 bytes length of the Ethernet frame in bytes
Data. n bytes payload of the frame min of 46 bytes max 1500 bytes
Frame check sequence FCS. 4 bytes uses 32-bit cyclic redundancy check value to check for errors
What is a MAC address
A physical address unique to every networking device assigned by its manufacturer. Six bytes long
First three bytes identify the manufacturer called OUI organizational unique identifier.
Last three bytes id the device and called universal LAN MAC address
What is a networking standard
Set of specs, guidelines, or characteristics applied to network components
Ex IEEE 802.3 Ethernet standard
List some of the standards organizations
ISO. International Organization for Standards.
IEEE. Institute of Electrical and Electronics Engineers
ANSI. American National Standards Institute
TIA. Telecommunications Industry Association
EIA. electronic Industries Alliance
IETF. Internet Engineering Task Force
The 10Base standard describe
The media type and speed each media operatrs. Cable specs include media speed, signal type and code for copper or fiber
Ex 10base-2 is 802.3a ThinNet coax
10Base-5 is 802.3 ThickNet coax
Fast Ethernet is
Ethernet that transmits data at 100 Mbps. Max length of cable is 250 meters. Used as a backbone network to interconnect several LANs
For Copper cat5 100Base-TX most widely used
Gigabit Ethernet is
Ethernet transmits data using optical fibers at 1000 Mbps.
1000Base-T 802.3ab.
10 Gigabit Ethernet is
Currently the highest speed Ethernet operates. Speeds at 10 Gbps
Describe the two ring based networks
Token ring. Computers pass bits called token. Only the node holding the token can transmit on the network.
FDDI Fiber Distributed Data Interface. Uses single mode or multimode fiber that transmits data at 100 Mbps. Has dual fiber rings only one ring carries data. The second ring is either idle or carries control signals.
Wireless LAN WLAN is
Self contained network of two or more computers connected using a wireless connection. Spans a small area and consists of client systems and wireless connectivity devices.
What is a wireless antenna
A device that converts high frequency signals in a cable into electromagnetic waves and vice versa. Receives and transmits radio waves. The higher the frequency the shorter the wavelength of the signal and the shorter the antenna will be
What is gain in reference to antennas
Signal strength. An increase in the amplitude of a radio wave.
Name wireless antenna types
Directional. Concentrates the signal beam in one direction. Have narrow focused transmission beam and relatively high gain. Must be precisely aligned.
Omni-directional. Radiates the signal best in all directions. Has lower gain because signal power is not focused but wider coverage. Doesn’t need to be precisely aligned. More potential sources for interference
WLAN architecture components
Station STA. Connects IEEE 802.11 MAC interface to a wireless medium with an Ethernet like driver interface.
Access point AP. device or software that facilitates communication and provides enhance security to wireless devices. Extends range of WLAN
Distribution system DS. wired connection between BSS and premise wide network that enables mobility to devices
Basic service set BSS. service set defines WLAN configuration either BSS, IBSS Or ESS
extended service set ESS. multiple BSSs
Independent basic service set IBSS. peer to peer network each wireless station acts as a client and a wireless AP
802.11 standards
Specs for wireless technologies
- 11b 2.4 GHz frequency
- 11n 2.4 or 5 GHz frequency
What is latency
The time taken by a data packet sent through wireless connection from a requesting device to the receiving device and back.
802.11 modes
Infrastructure mode. Utilizes one or moe WAPs to connect workstations to the cable backbone. BSS Or ESS
Ad-hoc mode. Also called IBSS utilizes peer to peer configuration so each wireless workstation talks directly to the other workstation.
892.11 beacon frames
Management frames that are 50 bytes long and used to start and maintain wireless communications. Contain info about the process such as SSID, channel number and security protocol information. Sent by APs
Wireless access point WAP placement considerations
Building layout Coverage area Clients Obstacles Interference
