Telecommunications and Network Security Flashcards
Data Network Types are
LAN ( local area network ) and WAN ( wide area network )
( ! ) A data network that operates over a small geographical area such as a building floor etc that can be wired or wireless ( or both ) is a
LAN ( Local Area Network )
A LAN operates on the following layers of OSI
PHYSICAL and DATA LINK
( ! ) A data network that operates over a relatively large geographic area and may connect LANs and WANs via telecommunications is a
WAN ( Wide Area Network )
A WAN on the following layers of OSI
PHYSICAL, DATALINK and NETWORK
Internet, Intranet and Extranet are examples of a
WAN
What is OSI Reference model established by the ISO ( International Standards Organization )
OPEN SYSTEMS INTERCONNECTION defines standard protocols for communication and interoperability by a layered approach. Facilitates operation between network devices.
The OSI model consists of ( ? ) Layers
( 7 ) SEVEN
LAYER 1
PHYSICAL
LAYER 2
DATA LINK
LAYER 3
NETWORK
LAYER 4
TRANSPORT
LAYER 5
SESSION
LAYER 6
PRESENTATION
LAYER 7
APPLICATION
LAYERS communicate with the layers
ABOVE AND BELOW ( ADJACENT )
LAYERS communicate via
DATA ENCAPSULATION
PHYSICAL is LAYER
ONE ( 1 )
DATA LINK is LAYER
TWO ( 2 )
NETWORK is LAYER
THREE ( 3 )
TRANSPORT is LAYER
FOUR ( 4 )
SESSION is LAYER
FIVE ( 5 )
PRESENTATION is LAYER
SIX ( 6 )
APPLICATION is LAYER
SEVEN ( 7 )
Physical Layer is responsible for
sending and receiving bits across the network cabling from one device to another.
PHYSICAL specifies
ELECTRICAL, MECHANICAL, and FUNCTIONAL requirements of the network.
Physical Layer consists of
NETWORK TOPOLOGY, CABLING AND CONNECTORS, INTERFACES, and process for converting bits to SIGNALS that can be transmitted across a physical medium.
Network Topologies types
STAR, MESH, RING, BUS
In a STAR topology each individual note on the network is directly connected to
a SWITCH, HUB or Concentrator. It is the most common basic topology it is easy to install and maintain.
ALL TRAFFIC pass through a HUB or SWITCH can become a
BOTTLENECK or Single Point of Failure.
In a MESH topology
all systems are interconnected providing multiple paths to all resources.
In a RING topology
all devices are connected in a continuous RING all communications travel in a single direction.
In a BUS ( linear ) topology
all devices are connected to a single cable that is terminated at both ends. Commonly used for small networks.
CABLE AND CONNECTOR types
COAXIAL, TWINAXIAL, TWISTED PAIR, FIBER OPTIC,
ANALOG Signaling conveys information via
waves by variation of amplitude, frequency and phase
DIGITAL Signaling conveys information via
pulses through presence of on / off electrical signals.
( ! ) A US military TERM that refers to the study of electromagnetic emissions from computers and computer related equipment
TEMPEST
( ! ) Network Topology, cable connector types, and interfaces are defined at the ( X ) layer of the OSI model
PHYSICAL
Networking equipment that operates at the PHYSICAL layer consist of
NICs, Network Media ( cabling and connectors) , Repeaters and HUBs.
Repeaters are a non intelligent device which serves to
amplify signals against loss to allow for extension of cable segments.
A HUB ( concentrator ) is used to connect LAN devices together two types are
PASSIVE / ACTIVE
( ! ) DATA LINK LAYER is responsible for ensuring
messages are delivered to a proper device on the physical networking link, it defines networking protocol.
DATA LINK LAYER consists of two sub layers of control
LOGICAL LINK and MEDIA ACCESS
LAYER 2 Protocols are
ARP and RARP.
ARP maps an IP address to a
MAC ADDRESS
ARP is used to identify
a device’s HW address when only the IP address is know.
RARP maps an MAC address to a
IP ADDRESS
RARP is used to identify
a device’s IP ADDRESS when the MAC address is known.
LAN DATA Transmissions are classified as
UNICAST, MULTICAST and BROADCAST
