Chapter 2 Review Questions Flashcards
In the accompanying graphic, what is the name for the section of the MAC address marked as unknown?
D. The organizationally unique identifier (OUI) is assigned by the IEEE to an organization composed of 24 bits, or 3 bytes, which in turn assigns a globally administered address also comprising 24 bits, or 3 bytes, that’s supposedly unique to each and every adapter it manufactures.
___________ on an Ethernet network is the retransmission delay that’s enforced when a collision occurs.
A. Backoff on an Ethernet network is the retransmission delay that’s enforced when a collision occurs. When that happens, a host will only resume transmission after the forced time delay has expired.
Back-off algorithm is a collision resolution mechanism which is used in random access MAC protocols (CSMA/CD). This algorithm is generally used in Ethernet to schedule re-transmissions after collisions.
If a collision takes place between 2 stations, they may restart transmission as soon as they can after the collision. This will always lead to another collision and form an infinite loop of collisions leading to a deadlock. To prevent such scenario back-off algorithm is used
On which type of device could the situation shown in the diagram occur?
Hub. When using a hub, all ports are in the same collision domain, which will introduce collisions as shown between devices connected to the same hub.
In the Ethernet II frame shown here, what is the function of the section labeled “FCS”?
Error detection. FCS is a field at the end of the frame that’s used to store the cyclic redundancy check (CRC) answer. The CRC is a mathematical algorithm that’s based on the data in the frame and run when each frame is built. When a receiving host receives the frame and runs the CRC, the answer should be the same. If not, the frame is discarded, assuming errors have occurred.
A network interface port has collision detection and carrier sensing enabled on a shared twisted-pair network. From this statement, what is this Ethernet port operating at?
This is an Ethernet port operating at half-duplex. Half-duplex Ethernet networking uses a protocol called Carrier Sense Multiple Access with Collision Detection (CSMA/CD), which helps devices share the bandwidth evenly while preventing two devices from transmitting simultaneously on the same network medium.
For what two purposes does the Ethernet protocol use physical addresses?
To uniquely identify devices at layer 2.
To allow communication between different devices on the same network
Physical addresses or MAC addresses are used to identify devices at layer 2. MAC addresses are only used to communicate on the same network. To communicate on different network, we have to use layer 3 addresses (IP addresses).
Between which systems could you use a cable that uses the pinout pattern shown here using switch, router, and/or host?
Switch and Hubs on one side. Router and PC on the other. The cable shown is a straight-through cable, which is used between dissimilar devices.
In an Ethernet network, under what two scenarios can devices transmit?
- When they detect that no other devices are sending.
- When the medium is idle
An Ethernet network is a shared environment, so all devices have the right to access the medium. If more than one device transmits simultaneously, the signals collide and cannot reach the destination.If a device detects another device is sending, it will wait for a specified amount of time before attempting to transmit. When there is no traffic detected, a device will transmit its message. While this transmission is occurring, the device continues to listen for traffic or collisions on the LAN. After the message is sent, the device returns to its default listening mode.
What type of cable uses the pinout shown here? Also which pins would you connect together?
Crossover Gigabit Ethernet cable. In creating the gigabit crossover cable, you’d still cross 1 to 3 and 2 to 6, but you would add 4 to 7 and 5 to 8.
When configuring a terminal emulation program and when you set up the connection, what settings do you use?
Bits per sec: ___
Data bits: ___
Parity: ___
Stop bits: ___
Flow control: ___
D. When you set up the connection, use these settings:
Bits per sec: 9600
Data bits: 8
Parity: None
Stop bits: 1
Flow control: None
Which part of a MAC address indicates whether the address is a locally or globally administered address? And how do you know when it is locally o globally?
U/L bit. When set to 0, this bit represents a globally administered address, as specified by the IEEE, but when it’s a 1, it represents a locally governed and administered address.
What cable type uses the pinout arrangement shown below?
Rolled. You can use a rolled Ethernet cable to connect a host EIA-TIA 232 interface to a router console serial communication (COM) port.
Which of the following statements is false with regard to Ethernet?
There are ____ collisions in full-duplex mode.
A ____ port is required for each full-duplex node.
The ____ and the ____ must be capable of operating in full-duplex mode to use full-duplex.
The default behavior of 10Base-T and 100Base-T hosts is ______ if the autodetect mechanism fails
There are no collisions in full-duplex mode.
A dedicated switch port is required for each full-duplex node.
The host network card and the switch port must be capable of operating in full-duplex mode to use full-duplex.
The default behavior of 10Base-T and 100Base-T hosts is 10 Mbps half-duplex if the autodetect mechanism fails
In the following diagram, identify the cable types required for connections A and B.
A= B=
A= crossover, B= straight-through. The connection between the two switches requires a crossover and the connection from the hosts to the switches requires a straight-through.
In the following image, match the cable type to the standard with which it goes.
The given cable types are matched with their standards in the following table.
What cable type is shown in the following graphic?
Fiber-optic cables are the only ones that have a core surrounded by a material called cladding
