1 - Basic Networking Flashcards
What IEEE standard number covers all Ethernet standards?
802.3
What suffixes are used for UTP cabling and Fiber cabling in informal IEEE Ethernet standard names?
T for UTP
X for Fiber
What are the IEEE standard and names for Ethernet and Fast Ethernet?
10BASE-T (802.3)
100BASE-T (802.3u)
What are the IEEE standard and names for both UTP and Fiber Gigabit Ethernet?
1000BASE-LX (802.3z) Fiber
1000BASE-T (802.3ab) UTP
What is the IEEE standard and name for 10 Gig Ethernet?
10GBASE-T (802.3an)
How many twisted pairs does 10BASE-T and 100BASE-T require?
2
How many twisted pairs does 1000BASE-T require?
4
Which twisted pair wire / pin numbers do Ethernet NICs and Routers use to transmit and receive on respectively?
Transmission on pins 1 and 2
Receive on pins 3 and 6
Which twisted pair wire / pin numbers do Switches use to transmit and receive on respectively?
Transmission on pairs 3 and 6
Receive on pins 1 and 2
What type of cable must be used to connect a PC NIC to a switch?
Straight through cable. (1-1, 2-2, 3-3, 6-6, etc)
What type of cable is used for connecting nodes that use opposite pairs for transmitting? e.g. PC NIC / Router to Switch?
Straight through cable
What type of cable must you use for connecting like devices that transmit on the same pins? e.g Hub, Switch to Switch (10 and 100 Mbps Ethernet)
Crossover cable
In 10BASE-T and 100BASE-T which types of devices transmit on Pins 1 and 2?
Routers, PC NICs and Wireless access points (Ethernet interface)
In 10BASE-T and 100BASE-T which two types of devices transmit on Pins 3 and 6?
Switches and Hubs
What is auto-mdix?
A feature on Switches that detects when the wrong cable is used and automatically changes the logic to make the link work
What are the layers of a Fiber Optic Cable?
Core, Cladding, Buffer, Strengthener, Outer jacket
What mode of Fiber allows for multiple angles (modes) of light entering the core? What type of transmitter is used?
Multimode. LED
Which mode of fiber uses a smaller core with a transmitter sending light at one angle? What type of transmitter is used?
Single mode. Laser
What is SFP/SFP+?
Small Form Pluggable, allow customer to change transceiver as module in Switches. E.g. switch to optical fiber ethernet
What mode of Fiber is useful for very long distances?
Single mode
List the following cable modes in order of least expensive to most expensive: Multi-mode fiber, UTP, Single-mode fiber?
UTP, Multi-mode, Single-mode
What does Half Duplex mean for a device?
The device can only send when it is not receiving a frame i.e. it cannot send and receive a frame at the same time
What does Full Duplex mean for a device?
A device can send and receive at the same time
What layer of standards does a Hub use to forward data, and how does it do this?
Physical layer standards. A hub repeats electronic signals out all ports (except incoming)
What is a big downside of LAN hubs?
If more than one device transmits at the same time, the signals collide and become messed up
How does CSMA/CD work?
Sending device listens to link until its free. Sends a frame. If device detects a collision, all devices send a jamming signal, wait a random amount of time, then try again
How many bytes are in an Ethernet FCS? Where is it located?
4 bytes. In the Ethernet Trailer
How many bytes is the Ether Type field?
2 bytes
What are the two most popular Data link layer protocols for leased lines between two routers?
HDLC (High level data link control) and PPP
What is the Flag field in HDLC used for and whats its Ethernet equivalent?
Recognizable bit pattern so receivers know a new frame is arriving. Equivalent to Preamble, SFD
What field is proprietary to each vendor in HDLC?
Type field
What function does HDLC provide?
HDLC frames provide a way to encapsulate network layer packet correctly so it crosses the link between routers.
What protocol is broadcast, multi access?
Ethernet
What protocol is non broadcast, point to point?
HDLC
Do Serial interfaces have MAC addresses? Why?
No. They do not need them. Serial interfaces are only used for Point to Point links
What is an Ethernet Line Service (E-Line)?
Term for the point to point Ethernet WAN service
What is Ethernet emulation?
A term highlighting a link is not a literal Ethernet link from end to end
What is EoMPLS?
Ethernet over Multi Protocol Label Switching. Used to create Ethernet service. Acts as if it were a simple Ethernet link between two routers
What port does DNS use?
53
What port does TCP use?
57
Do Optical cables suffer from EMI?
No
What is macro-bending?
If a fiber-optic cable is bent too much, and it prevents the cable transmitting bits
