Computer Networks 1: Link Layer

<p>It has unique challenges and demands not seen in upper layers. (B)</p> Signup and view all the answers

<p>Some errors, though it rarely occurs (A)</p> Signup and view all the answers

<p>ARP (C)</p> Signup and view all the answers

<p>Transmission and integrity of data (C)</p> Signup and view all the answers

<p>A higher likelihood of false negatives in error detection (A)</p> Signup and view all the answers

<p>Detect single bit errors (A)</p> Signup and view all the answers

<p>It can correct single bit errors (D)</p> Signup and view all the answers

<p>The total number of 1's must be even (D)</p> Signup and view all the answers

<p>To detect errors in transmitted segments (C)</p> Signup and view all the answers

<p>Compute the checksum of the received segment (A)</p> Signup and view all the answers

<p>No errors were detected (B)</p> Signup and view all the answers

<p>Addition (one's complement sum) of the segment content (D)</p> Signup and view all the answers

<p>Single bit parity (A)</p> Signup and view all the answers

<p>Transferring datagrams from one node to an adjacent node. (A)</p> Signup and view all the answers

<p>Frame (A)</p> Signup and view all the answers

<p>The source and destination nodes. (A)</p> Signup and view all the answers

<p>Congestion control across multiple networks. (D)</p> Signup and view all the answers

<p>WiFi providing the first link followed by Ethernet. (D)</p> Signup and view all the answers

<p>Transportation modes for travelers between cities. (B)</p> Signup and view all the answers

<p>It ensures the integrity of data delivered over the link. (D)</p> Signup and view all the answers

<p>The ability of one device to share a channel with multiple devices. (C)</p> Signup and view all the answers

<p>A network that connects a limited geographical area, usually within one building. (B)</p> Signup and view all the answers

<p>The travel agent managing connections. (D)</p> Signup and view all the answers

<p>It can allow a single active node to transmit continuously at full rate. (A)</p> Signup and view all the answers

<p>Each node is assigned exclusive use of a channel piece. (C)</p> Signup and view all the answers

<p>It can lead to wasted slots due to collisions. (A)</p> Signup and view all the answers

<p>The highest fraction of slot usage for successful transmissions. (B)</p> Signup and view all the answers

<p>They are ignored and not used in the next round. (C)</p> Signup and view all the answers

<p>Np(1-p)N-1 (B)</p> Signup and view all the answers

<p>By assigning each station a fixed frequency band. (D)</p> Signup and view all the answers

<p>Nodes transmit only when they have data to send. (D)</p> Signup and view all the answers

<p>Determine the optimal probability p* that maximizes Np(1-p)N-1. (B)</p> Signup and view all the answers

<p>Time is divided into slots for fixed length data transmission. (A)</p> Signup and view all the answers

<p>Nodes must wait for a certain interval before attempting to resend. (B)</p> Signup and view all the answers

<p>Those nodes have no data to send. (D)</p> Signup and view all the answers

<p>TDMA divides time, while FDMA divides frequency. (C)</p> Signup and view all the answers

<p>To detect burst errors in data transmission (D)</p> Signup and view all the answers

<p>Data bits and generator bit pattern (D)</p> Signup and view all the answers

<p>An error has been detected (B)</p> Signup and view all the answers

<p>Ethernet (D)</p> Signup and view all the answers

<p>A direct connection between two devices (A)</p> Signup and view all the answers

<p>They involve multiple users sharing a communication medium (D)</p> Signup and view all the answers

<p>The number of CRC bits chosen for error detection (C)</p> Signup and view all the answers

<p>It requires the receiver to know the generator pattern (A)</p> Signup and view all the answers

<p>A sequence of bits that all malfunction (C)</p> Signup and view all the answers

<p>They are characterized by a direct connection between two endpoints (C)</p> Signup and view all the answers

EDC bits are added to data to detect and sometimes correct errors during transmission.

The link layer checks data for errors before transferring it to the next layer.

A packet of data transmitted through a network.

Error detection isn't foolproof; some errors might go undetected.

A larger EDC field improves error detection and correction.

A link that has a high chance of transmitting data with errors.

A piece of data that has EDC attached for error detection.

The link layer is critical for ensuring data integrity during transmission.

The layer in the network that handles communication between adjacent network nodes on a single link.

Includes framing (encapsulation of data), link access (managing shared channels), and reliable delivery between adjacent nodes.

A packet at the link layer, encapsulating data from a higher layer (like an IP datagram).

A unique address identifying a device on a local network (e.g., Ethernet).

A physical or wireless communication channel connecting adjacent network nodes.

A device participating in a network (a computer, router, etc.).

Protocols governing how multiple devices share a common link or channel.

Methods used by the link layer to identify and correct errors that occur during data transmission.

A network covering a geographically small area, like a home or office.

A method for detecting a single bit error in data.

A method for detecting and correcting single bit errors by using both row and column parity bits.

A parity scheme where the parity bit is set so that there is an even number of 1s.

A method used by the sender and receiver to detect errors in transmitted network segments.

Sender calculates the checksum by treating the segment's content as a sequence of 16-bit integers and adding them using one's complement.

Receiver computes the checksum of the received segment and compares it to the sender's checksum.

If the computed checksums don't match, an error is detected.

This method detects errors but doesn't correct them; it's part of error detection mechanism.

A multiple access protocol where time is divided into slots, and nodes can only transmit during their assigned slots. This reduces collisions, but still allows for some wasted slots.

When multiple nodes attempt to transmit during the same slot, their data collides and becomes unusable.

The efficiency measures the percentage of successful transmissions in a given time. The theoretical maximum efficiency is 1/e, which is about 37%.

'p' represents the probability that a node will transmit in a given slot. It's a crucial factor influencing the overall efficiency of the system.

The maximum efficiency is limited by the inherent possibility of collisions. Even with carefully calculated probability, collisions will always occur to some extent.

Rules governing how devices share a network channel (e.g., wireless or wired). There are three main categories: channel partitioning, random access, and taking turns.

Divides the network channel into smaller pieces (time slots, frequencies, or codes) so devices can have exclusive access to specific parts.

Allows devices to transmit data whenever they want, but collisions can occur. There are mechanisms to recover from these collisions.

Divides transmission time into fixed-length 'slots'. Each device gets a slot in each round, allowing it to transmit data exclusively during its slot.

Divides the available frequency spectrum into bands. Each device is assigned a band, allowing it to transmit on that frequency.

When two or more devices transmit data simultaneously on a random access network, their signals interfere, resulting in a collision.

Random access protocols have mechanisms to detect and recover from collisions, such as backoff strategies (devices wait a random time before trying again) and retransmission (devices retransmit the data after a collision).

Devices take turns transmitting data, but devices with more data can have longer turns. This ensures fairness and efficient resource allocation.

A more robust error-detection mechanism that utilizes a generator polynomial to calculate a 'checksum' and verify data integrity.

A specific bit pattern (r+1 bits) used in CRC calculations to detect errors. The receiver knows G and uses it to divide the received data, looking for a zero remainder.

The result of the CRC calculation, a set of bits added to the data to help detect transmission errors.

The goal is to choose a set of CRC bits (R) that will be exactly divisible by the generator polynomial (G) when added to the original data (D). This ensures a zero remainder after division at the receiver, indicating no errors.

The receiver calculates the CRC using the received data and the known generator polynomial. If the remainder is non-zero, an error is detected.

CRC can detect all burst errors (multiple consecutive bits flipped) less than r+1 bits in length.

A direct connection between two devices, like a single cable between a host and an Ethernet switch.

A communication medium where all devices on the link listen to every transmission, such as a typical cable network or wireless LAN.

A widely used networking protocol for local area networks (LANs), supporting both point-to-point and broadcast communications.

A standard for wireless local area networks, utilizing radio waves to connect devices.