Lesson 4 Objectives Flashcards
Most LAN networks are based on which ethernet standards?
802.3
The IEEE 802.3 standards are designated how and what does it mean?
X base T
IEEE = Institute of Electrical and Electronics Engineers
x BASE- Y
x = nominal data rate
Y is cable type
100BASE-T=Fast ethernet/copper twisted pair cable. ethernet 100 Mbps
1000BASE-T refers to Gigabet ethernet over copper twisted pair cabling. gigabit ethernet works at 1000 Mbps or 1 Gbps.
What is the mainstream / most popular standard for 802.3 LAN
xBASE-Y
1000BASE-T
Gigabit ethernet over copper twisted pair cabling at 1 Gbps (1000 Mbps)
What are the two main types of ethernet cabling?
Copper and Fiber Optic
How does Copper Cabling communicate data?
Electrical Signaling
How does Fiber Optics communicate data?
Pulses of Light
What does WLAN use to send / receive data?
Wireless Local Area Network
radios and antennas
What standards are most WLAN’s based on?
IEEE Standards / Wireless Local Area Network
802.11
IEEE 802.11 is known by what Brand Name?
Wi-Fi
One example of a WAN is what?
Wide Area Network
The Internet
How are most WAN’s connected?
Wide Area Network
use cabling and equipment leased from an ISP to interconnect two or more LAN sites.
ISP = Internet Service Provider
LAN = Local Area Network
What is the difference between networks supporting SOHO and those supporting larger buisnesses or academic institutions?
SOHO Small office home office
They have the same networking appliances and basic functions but, larger networks must support more clients with a greater degree of reliability.
Each function is performed by a separate network device.
in larger business networks, the internet servics are placed where?
in protected screened subnets, which represent the border between the private LAN and the public internet.
Traffic to / from is strictly monitored and filtered.
Most networks distinguish between two basic roles for the computers
- a server computer–dedicated to running network applications and hosting shared resources
- a client computer allowing end users to access the applications and resources to do work
A SAN is only accessed by what?
Storage Area Network
The servers
it’s completley isolated from the main network.
Who are SAN clients?
Storage Area Network
Servers running databases or applications.
What kind of connectivity technology do SAN’s use?
Storage Area Network
Fibre Channel and Internet SCSI (iSCSI)
Where is the transceiver port located?
In a computer’s NIC.
Network interface card
What kind of adapter do the majority of PC motherboards have built into the NIC?
Network Interface Card
xBASE-Y
1000BASE-T
Compatible adapter
What effect would purchasing cards with multiple NIC ports of the same type such as 1000BASE-T have?
The multiple ports can be bonded to create a higher-speed link.
4 Gigabit Ethernet ports could be bonded to give a link speed of 4 Gbps
What does the NIC need to be able to process the electrical or light signals as digital data?
(2)
Network Interface Card
- Signals (electrical or light) must be divided into regular units with a consistent format.
- Must be a means for each node on the LAN to address communications to other nodes
Local Area Network
Ethernet provides a data link protocol to perform these framing and addressing functions
Each ethernet NIC has a unique what?
Network Interface Card
hardware / physical address
called the MAC media access control address
A MAC address has how many digits and what size?
Media Access Control
Consists of 48 binary digits
6 bytes in size
How is a MAC address usually represented?
Media Access Control
# and format
12 digits of hexadecimal.
What values can a hex digit be represented as and how many are there?
There are 16 values
0-9
A, B, C, D, E, F
What kind of spacing is used to represent MAC addresses?
Media Access Control
written with a colon or hypen separaters or no separaters at all.
How is most cabling connected / run in an office.
connected to a wall port
run via cabling through the walls
to a patch panel.
what kind of ports will you find on the other side of a patch panel?
There are prewired RJ45 ports
How many ports does a hub usually have?
Between 4 and 48
Each computer is cabled to one port
How are transmissions sent through hubs?
the circuitry in the hub repeats an incoming transmission from a computer attached to one port across all the other ports. Essentially, the computers seem attached to the same cable. each attached computer receives all the traffic sent by other connected devices.
How do computers receive the correct transmissions in hubs or collision domains wherein all connected computers receive every transmission?
Each computer ignores any frames that do not match it’s MAC address
Media Access Control
What is one consequence of having too many computers connected to a hub?
Performance is reduced.
All computers receive all transmissions, too many and it would slow down all the computers
On computers connected to a hub, what happens if two or more computers try to send at the same time?
there is a collision and they must wait for a random period before trying again.
What circumstance might you find a hub still used today?
where legacy equipment must be kept in service.
Almost all networks are now based on what instead of hubs?
Ethernet Switching
What kind of configuration does an unmanaged switch support?
An unmanaged switch doesn’t support any kind of configuration.
Ethernet switches are a solution to what problem?
collision domains
Collision domains found within hub networks
What does an ethernet switch have in common with a hub?
They both have one port for each device that connects to the network
What’s different about ethernet switches and hubs?
Ethernet switches can decode each frame and identify source and destination MAC addresses.
Switches can track which MAC source addresses are associated with each port. when it receives an incoming frame, the switch intelligently forwards it to the port that’s a match for it’s destination MAC address.
Media Access Control
With ethernet switches, does each computer have half-duplex or full-duplex connections to the network?
Full-Duplex
Half-Duplex can send and receive but not at the same time
Full-Duplex can send and receive at the same time
What happens if an ethernet switch reads the source address and doesn’t have the MAC address in it’s table of known-addresses yet?
Media Access Control
the switch floods the frame out to all ports to find the associated MAC address
Media Access Control
What is an unmanaged switch?
performs its function wihtout requiring any sort of configuration.
you power it on and connect some hosts to it and it establishes ethernet connectivity between the network interfaces without any more intervention.
How many ports might you find in unmanaged switches?
4-8
where are unmanaged switches often found?
small networks and SOHO router / modems provided by ISP’s to connect to their network
SOHO=Small office home office
ISP = Internet Service Provider
What are managed switches?
ethernet switch that’s configurable via a command-line interface or SDN controller
SDN = Software-Defined Networking
How does a managed switch function out of the box?
like an unmanaged switch
How do you configure a managed switch
The admin connects it over to a managment port, configures security settings, and chooses options for the switches more advanced functionality.
how many access ports does a typical switch come with?
24-48 and have uplink ports allowing them to be connected to other switches
how can you configure a managed switch?
Over the web or a command line interface
How much power can PoE Devices draw?
Power over Ethernet
13 W
or
25 W for PoE+
Name 3 IEEE PoE standards
IEEE= Institute of electrical and electronic engineers
PoE = Power over Ethernet
- 802.3af
- 802.3at
- 802.3bt
802.3af is what kind of standard?
IEEE PoE
IEEE= Institute of electrical and electronic engineers
PoE = Power over Ethernet
How much power does 802.3af use?
PoE standard
13 W–15.4W
Voltage drop over max 100m cable = usable power of around 13 W
802.3af allows how much power?
PoE Standard
25 W with a maximum current of 600 mA
802.3bt is also called what?
PoE++ or 4PPoE
802.3at is also called what?
PoE+
802.3bt (PoE++ / 4PPoE) supplies how much power?
about 51 W (Type 3)
or
73 W (Type 4) Usable Power
a PoE-enabled switch is referred to as
endspan PSE
PSE=Power Sourcing Equipment
How does a PoE-enabled Switch work?
When a device is connected to a port on a PoE switch, the switch goes through a detection phase to determine whether the device is PoE enabled.
If so, it determines the devices power consumption and sets an appropriate supply voltage level.
If not, it does not supply power over the port and, therefore, doesn’t damage non-PoE devices.
What is the most popular type of network cable?
UTP
Unshielded Twisted Pair
What is a UPT made up of?
Unshielded Twisted Pair
4 copper conductor wire pairs
How are the copper wires in UTP twisted?
Unshielded twisted pair
each insulated pair twisted at a different rate from other pairs.
Why are UTP copper wire pairs twisted at different rates from the other pairs?
To reduce interference
The electrical signals in a UTP are balanced which means what?
Unshielded Twisted pair
Each wire carries an equal but opposite signal to its pair.
What is the maximum recommended distance for UTP?
Unshielded twisted pairs.
100 m
When are STP’s most often used?
2
Shielded Twisted Pair
for 10G ethernet and higher within datacenter networks
Also useful in environments with high levels of external interference such as cable run in proximity to flourescent lighting, power lines, motors and generators.
What 3 things is screened cable usually designated as?
ScTP
F/UTP
FTP
Screened Twisted Pair
Foiled / Unshielded Twisted Pair
Foiled Twisted Pair
Fully shielded cabling is referred to as what two things?
S/FTP
F/FTP
Shielded / Foiled Twisted Pair
Foiled (outer shield) / Foiled Twisted Piar
The screening / shielding elements of shielded cable must be bonded to what and for what purpose?
Must be bonded to the connector
To prevent the metal from acting as a large antenna and generating interference.
Which 2 types of twisted pairs facilitate bonding of cable to the connector to prevent interference by incorporating bonding within the design of each element?
F/UTP and S/FTP
Foiled / Unshielded Twisted Pair
Shielded / Foiled Twisted Pair
Higher Cat Specification =
Higher data rates
What would a Cat 5 cable’s Max Transfer rate and distance be?
100 Mbps
100 m
What would a Cat 5e’s Max transfer rate and Max Distance be?
1 Gbps
100m
What would a Cat 6a’s Max transfer rate and distance be?
10 Gbps
100 m
What Category of Twisted Pair Cables would be used for 10BGase-T Ethernet Support?
6A
What Cat Twisted Pair Cables would be used for 100Base-TX (Fast Ethernet) Support use?
5
Where is a Twisted Pair Cable’s Cat specification?
It’s Printed on the cable jacket along with the cable type such as UTP or F/UTP.
What Cat cables would most sites opt to install today?
Cat 6
What kind of connectors would be used to terminate twisted pair cabling for ethernet?
Modular RJ45
What else are RJ45 Connectors referred to as?
8P8C
What does 8P8C stand for?
8 Point 8 Contact
RJ45
in RJ45 Connectors, Ethernet cable is color-coded with each pair assigned a color. What are the colors?
6 (colors and what stripes and solid means)
Orange
Green
Blue
Brown
The first conductor in each pair has a white insulator with stripes of the color.
The second conductor has an insulator with solid color
What are the two methods for terminating Twisted Pairs?
T568A
T568B
What is the difference between T568A and T568B terminations for twisted pairs?
The color of the wires connected to each pin.
in T568A, What color wire is each pin connected to?
Pin 1: Green / White
Pin 2: Green
Pin 3: Orange / White
Pin 4: Blue
Pin 5: Blue / White
Pin: 6 Orange
Pin 7: Red / White
Pin 8: Red