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Chapter 2: Network Acces 2.1 Construct Physical layer protocols and…
Chapter 2: Network Acces
2.1 Construct Physical layer protocols and network media
2.1.1 Identify device connectivity options
Switches
-Switches are connectivity devices that subdivide a network into smaller logical pieces, or segments.
-Traditional switches operate at the Data Link layer of the OSI model.
-Modern switches can operate at Layer 3 or even Layer 4.
-Because they have multiple ports, switches can make better use of limited bandwidth and prove more cost efficient than bridges.
Router
-Router is a multiport connectivity device that directs data between nodes on a network.
-Routers can integrate LANs and WANs running at different transmission speeds and using a variety of protocols.
-Layer 3 (Network Layer) of OSI model.
Bridges
-Bridges are devices that connect two network segments by analysing incoming frames and making decisions about where to direct them based on each frame’s MAC address.
-They operate at the Data Link layer of the OSI model.
Wireless Access Point (AP
-Wireless Access Point (WAP) that allows a Wi-Fi compliant device to connect to a wired network.
-Mobility.
-WAP is differentiated from a hotspot, which is the physical location where Wi-Fi access to a WLAN is available.
Hub
-Hub is a repeater with more than one output port.
-Hub accepts signals from a transmitting node and repeats those signals to all other connected nodes in a broadcast fashion.
-Because of their limited features and the fact that they merely repeat signals within a single collision domain, hubs were replaced by routers and switches.
Modem
-Stand for Modulation and Demodulation.
-Convert either digital signal to analog signal (modulation) and analog signal to digital signal (demodulation)
Repeater
-Repeaters operate in the Physical layer of the OSI model-no means to interpret the data they retransmit.
-One input and output port - receiving and repeating a single data stream.
-Repeater allows you to extend a network inexpensively
Network Interface Card (NIC)
A network interface card (NIC) is a hardware component, typically a circuit board or chip, which is installed on a computer so that it can connect to a network.
NICs are designed for use with either wired or wireless networks.
On-Board NICs, via an expansion slot or peripheral bus
Wireless NICs, which contain antennas to send and receive signals wirelessly
2.1.2 Describe basic principles of the physical layer standards
Internet Standards
Internet Research Task Force (IRTF)
focused on long-term research related to Internet and TCP/IP protocols
Internet Corporation for Assigned Names and Numbers (ICANN)
coordinates IP address allocation and management of domain names
Internet Engineering Task Force (IETF)
develops, updates, and maintains Internet and TCP/IP technologies.
Internet Architecture Board (IAB)
management and development of Internet standards
Internet Assigned Numbers Authority (IANA)
manages IP address allocation, domain name management, and protocol identifiers for ICANN.
Internet Society (ISOC)
promotes open development and evolution of Internet use globally.
Electronics and Communications Standard Organizations
Electronic Industries Alliance (EIA)
standards related to electrical wiring, connectors, and network racks.
Telecommunications Industry Association (TIA)
standards for radio equipment, cellular towers, Voice over IP (VoIP) devices, and satellite communications.
Institute of Electrical and Electronics Engineers (IEEE)
dedicated to advancing technological innovation and creating standards in a wide area of industries including networking
International Telecommunications UnionTelecommunication Standardization Sector (ITU-T)
standards for video compression, Internet Protocol Television (IPTV), and broadband communications.
Open Standards
-encourage interoperability, competition, and innovation
-Standards organizations are usually vendor-neutral, non-profit organizations established to develop and promote the concept of open standards.
2.1.4 Cable used in Ethernet networks. Describe fiber optic cabling and its main advantages over other media
Characteristics of Copper Cabling
Copper Media
conducts electrical signals very well but it has its limitation.
data travels on copper cables as small pulses of electrical voltage cause it easily distorted by outside noise and signal attenuation.
cable type with shielding or twisting of the pairs of wires are designed to minimize signal degradation.
Shielded Twisted-Pair(STP) Cable
Coaxial Cable
Coaxial Connectors
BNC
N type
Ftype
Unshielded Twisted-Pair(UTP) Cable
used in Ethernet LANs
eight wires twisted into four color-coded pairs and then wound inside a cable jacket
colored pairs identify the wires for proper connection at the
UTP Cabling Standards
Category 5 and 5e Cable (UTP)
Used for data transmission
cat5 supports 100Mb/s and can support 1000 Mb/s, but it is not recommended
Cat5e supports 1000Mb/s
Category 6 Cable (UTP)
used for data transmission
an added separator is between each pair of wires allowing it to function at higher speeds
support 1000 Mb/s - 10 Gb/s, though q0Gb/s is not recommended
Category 3 Cable (UTP)
used for voice communication
most often used for phone lines
UTP Connectors
RJ-45 UTP Plugs
RJ-45 UTP Socket
Types of UTP Cable
T568A
T568B
Cable Type
Ethernet Straight - through
Standard
Both ends t568A or both ends T568B
Application
Connects a network host to a network device such as a switch or hub
Cable Type
Ethernet Crossover
Standard
One end T568A, other end T568B
Application
Connects two network hosts
connects two network intermediary device
Testing UTP Cables
UTP Testing Parameters:
Wire map
Cable length
Signal loss due to attenuation
Crosstalk
Copper Media Safety
Cables must be connected correctly
Installations must be inspected for damage.
The separation of data and electrical power cabling must comply with safety codes.
Equipment must be grounded correctly
Properties of Fiber Optic Cabling
Fiber Media Cable Design
Buffer
used to help shield the core and cladding from damage
Cladding
made from slightly different chemicals
used to create the core.
it tends to act like into the core the fiber.
keeps light in the core as it travels down the fiber
Core
actually the light transmission element at the center of the optical fiber.
typically silica or glass.
light pulses travel through the fiber core.
Strengthening Material
Surrounds the buffer, prevents the fiber cable from being stretched when it is being pulled
used is often the same material used to produce bulletproof vests.
Jacket
protects the fiber against abrasion, moisture and other contaminants.
can vary depending on the cable usage.
Types of Fiber Media
Single Mode
produces single straight path for light
small core
less dispersion
suited for long distance applications
uses lasers as the light source
commonly used with campus backbones for distances of several thousand meters
Multimode
Allows multiple paths for light
larger core than single mode cable
allows greater dispersion and therefore, loss of signal
suited for long distance applications, but shorter than single mode
uses LED as the light source
commonly used with LANs or distances of a couple hundred meters within a campus network
Network fiber Connectors
ST Connectors
SC Connectors
LC Connectors
Duplex Multimode Connectors
Testing Fiber Cables
optical time Domain Reflectometer (OTDR)
Fiber versus Copper
