Volume 1 - Chapter 2: Fundamentals of Ethernet LANs Flashcards
All ethernet standards fall under the scope of what IEEE designation?
802.3
What is the speed of the original Ethernet standard?
10 Mbps
What are the informal and formal IEEE standard names for the original Ethernet standard?
Informal: 10BASE-T
Formal: 802.3
What is the speed of the fast Ethernet standard?
100 Mbps
What are the informal and formal IEEE standard names for the fast Ethernet standard?
Informal: 802.3u
Formal: 100BASE-T
What is the speed of the gigabit Ethernet standard?
1 Gbps (1000 Mbps)
What are the informal and formal IEEE standard names for the gigabit Ethernet standard?
Informal: 1000BASE-LX or 1000BASE-T
Formal: 802.3z or 802.3ab
What is the speed of the ten-gigabit Ethernet standard?
10 Gbps
What are the informal and formal IEEE standard names for the ten-gigabit Ethernet standard?
Informal: 10GBASE-T
Formal: 802.3an
The process of a node sending data while the other node, the receiver, using the same rules, interprets those changes is referred to as?
An encoding scheme
The term “EMI” stands for?
Electromagnetic interference
Define the term “crosstalk” in regards to electromagnetic interference (EMI).
EMI between wire pairs in the same cable
Which Ethernet standards require 2 pairs of wires in the same cable?
10BASE-T and 100BASE-T
Which Ethernet standards require 4 pairs of wires in the same cable?
1000BASE-T or greater
Describe the purpose of a Gigabit Ethernet Interface Converter (GBIC).
The original form factor for a removable transceiver for Gigabit interfaces; larger than SFPs
What technology is used as the replacement for GBICs?
The Small-Form-Factor Pluggable (SFP)
Describe the difference between the SFP and SFP+
The sizes are the same, but SFP+ modules support speeds of 10 Gbps or higher
A PC is connected to a switch via straight-through 10BASE-T or 100BASE-T cable. Which pins on the PC connect to which pins on the switch?
Pins 1 & 2 on the PC connect to 1 & 2 on the switch, and pins 3 & 6 on the PC connect to pins 3 & 6 on the switch
When a PC is connected to a switch via straight-through 10BASE-T or 100BASE-T, which pins does the PC use to transmit and the switch to receive?
The PC uses pins 1 & 2 to transmit, and the switch receives on pins 1 & 2
When a PC is connected to a switch via straight-through 10BASE-T or 100BASE-T, which pins does the PC use receive and the switch use to transmit?
The switch transmits on pins 3 & 6, and the PC receives on pins 3 & 6
What cable is required to connect 2 nodes that use opposite pairs for transmitting data?
A straight-through cable
What cable is required to connect 2 nodes that use identical pairs for transmitting data?
A crossover cable
When 2 devices are connected via a crossover cable, which pairs are used for transmitting and receiving?
Both devices transmit on pairs 3 & 6 and both devices receive on pairs 1 & 2
What types of devices transmit on pairs 1 & 2?
PCs, Routers, and Access Points
What types of devices transmit on pairs 3 & 6?
Switches & hubs
What feature was added by the IEEE to Ethernet to allow devices to detect incorrect pinouts between devices and redirect the electrical signals to the correct pairs to compensate so that the link works?
Auto-MDIX
The term “auto-MDIX” stands for?
Automatic Medium-Dependent Interface Crossover
What pairs on a 1000BASE-T cable are used for transmitting and receiving?
All pairs can be used for transmitting and receiving simultaneously. The subsequent pairs are:
- 1 & 2
- 3 & 6
- 4 & 5
- 7 & 8
What pairs on a straight-through 1000BASE-T cable are connected on each end?
1 & 2 to 1 & 2
3 & 6 to 3 & 6
4 & 5 to 4 & 5
7 & 8 to 7 & 8
What pairs on a crossover 1000BASE-T cable are connected on each end?
1 & 2 to 3 & 6
4 & 5 to 7 & 8
The component of a fiber cable that reflects light back into the core is referred to as?
The cladding
The type of fiber cable that allows for multiple angles (modes) of light waves entering the core is referred to as?
Multimode
Multimode and single-mode fiber cables use which type of light source respectively?
Multimode: LED
Single-mode: Laser
Describe the size and purpose of the preamble in the 802.3 header.
Used for synchronize data transmission, 7 bytes
Describe the size and purpose of the SFD in the 802.3 header.
Start Frame Delimiter (SFD) is used to signify that the next byte begins the MAC destination address; 1 byte
Describe the size and purpose of the type field in the 802.3 header.
Defines the packet inside as either IPv4 or IPv6; 2 bytes
What is the size of the data and padding within the 802.3 frame?
46-1500 bytes, padding is added to meet the 46 byte minimum
Describe the size and purpose of the FCS field in the 802.3 trailer.
Frame Check Sequence (FCS) is used to detect if the frame contains transmission errors; 4 bytes
Describe the difference between half-duplex and full-duplex.
When sending data, half duplex devices must wait if they are currently sending data. Full duplex devices can send and receive simultaneously
Hubs are considered to operate at what layer of TCP/IP?
Layer 1
Describe the purpose of CSMA/CD.
Carrier Sense Multiple Access w/ Collision Detection is used to detect and recover from ethernet collisions in half-duplex networks
Network designs that utilize network hubs and CSMA/CD are classified as?
Ethernet Shared Media
Network designs that utilize network switches and full duplex are referred to as?
Ethernet
