Network+ Extra 9

Question 1

supports different communication sessions (for example, different telephone conversations in a telephony network) on the same physical medium by causing the sessions to take turns. For a brief period, defined as a time slot, data from the first session is sent, followed by data from the second session. This continues until all sessions have had a turn, and the process repeats itself.

Answer 1

Time-division multiplexing (TDM)

Question 2

divides a medium’s frequency range into channels, and different communication sessions send their data over different channels. As previously described, this approach to bandwidth usage is called broadband.

Answer 2

Frequency-division multiplexing (FDM)

Question 3

Senders and receivers of data frames need to coordinate when a data frame is being transmitted and should be received.

? : With ?, network devices look to a common device in the network as a clock source, which creates fixed-length time slots. Network devices can determine how much free space, if any, is available within a time slot and then insert data into an available time slot. A time slot can accommodate more than one data frame. ? does not need to provide clocking at the beginning of a data string (as does synchronous transmission) or for every data frame (as does asynchronous transmission). As a result, ? uses little overhead when compared to asynchronous or synchronous transmission methods.

Answer 3

Synchronizing transmissions (Isochronous transmission)

Question 4

Synchronizing transmissions has 3 modes :

With ?, network devices reference their own internal clocks, and network devices do not need to synchronize their clocks. Instead, the sender places a start bit at the beginning of each data frame and a stop bit at the end of each data frame. These start and stop bits tell the receiver when to monitor the medium for the presence of bits.

Answer 4

asynchronous (synchronizing transmissions)

Question 5

Synchronizing transmissions has 3 modes :

two network devices that want to communicate between themselves must agree on a clocking method to show the beginning and ending of data frames. One approach to providing this clocking is to use a separate communications channel over which a clock signal is sent. Another approach relies on specific bit combinations or control characters to indicate the beginning of a frame or a byte of data. Like asynchronous transmissions, ? can perform error detection. However, rather than using parity bits, ? communication runs a mathematical algorithm on the data to create a cyclic redundancy check (CRC). If both the sender and the receiver calculate the same CRC value for the same chunk of data, the receiver can conclude that the data was not corrupted during transmission.

Answer 5

synchronous (synchronizing transmissions)

Question 6

With packet switching, a data stream is divided into packets.

Circuit switching dynamically brings up a dedicated communication link between two parties for those parties to communicate.

Answer 6

packet/circuit switching

Question 7

TCP communication uses ?, in that one or more segments are sent at one time, and a receiver can attest to the receipt of all the segments in a ______ with a single acknowledgment.

Answer 7

Windowing

Question 8

? decrements by 1 everytime packet is routed from one IP network to another and goes until 0 and helps prevent routing loops.

Answer 8

TTL

Question 9

A switch elected to act as a reference point for a spanning tree. The switch with the lowest bridge ID (BID) is elected as the ?. The BID is made up of a priority value and a MAC address.

Answer 9

Root bridge

Question 10

All other switches in the STP topology are ? bridges.

Answer 10

Nonroot bridge