📝 RTCP Real time Transport Control Protocol (27 MCQs)

📖 Explanation: The encoded form lists the count of each character: 3+4+1+6+3 = 17. Adding the individual run lengths reconstructs the original sequence, so the uncompressed length is 17 symbols. This simple arithmetic demonstrates how run‑length encoding preserves total symbol count.

📖 Explanation: A longer interval means fewer RTCP packets are transmitted per unit time, directly reducing the amount of control traffic on the network. Because each report consumes a small but non‑zero number of bytes, sending them less frequently cuts the bandwidth contribution proportionally.

📖 Explanation: Run‑length coding converts the repeated characters into count‑symbol pairs (3A4B1C6D3E), reducing the total symbol count dramatically. Huffman coding, while optimal for variable‑frequency symbols, does not exploit the long runs as effectively, so the run‑length result is more compact for this specific pattern.

📖 Explanation: Longer intervals mean that loss statistics are reported less frequently, giving the sender more time before it learns about missing packets. Consequently, the detection of loss becomes slower, which can delay corrective actions such as bitrate reduction or retransmission requests.

📖 Explanation: The ratio is calculated as 16 ÷ 10 = 1.6. This indicates that the compressed data occupies about 62 % of the original size, or equivalently that the original data is 1.6 times larger than the compressed version. The figure is often rounded to 1.6 for simplicity.

📖 Explanation: A sender report conveys the sender’s transmission statistics, while a receiver report provides feedback on the quality of the received stream, notably packet loss, jitter, and round‑trip time. Thus the receiver report supplies the loss information that the sender can use for adaptation.

📖 Explanation: RTCP is the Real‑Time Control Protocol, which works alongside RTP to convey control information such as participant statistics, synchronization data, and feedback about the quality of the media streams.

📖 Explanation: The “R” in Run‑Length Encoding denotes “Run,” referring to a consecutive sequence of identical symbols. The algorithm records the length of each run followed by the repeated symbol, enabling reconstruction of the original data from the compact representation.

📖 Explanation: Losing exactly every fifth packet suggests a regular, repeating pattern rather than random or bursty behavior. This periodicity often points to a systematic issue such as a scheduling anomaly or a deterministic network impairment that repeats at a fixed interval.

📖 Explanation: If the timestamp moves backward, the most likely explanation is that the sender’s clock has drifted or been adjusted, causing its internal time base to lag behind the previously reported value. Network reordering would not affect the timestamp value itself.

📖 Explanation: In many run‑length schemes a zero count signals that the current symbol does not repeat, effectively marking the start of a new symbol. Therefore 0A means the first symbol appears only once before a new run begins.

📖 Explanation: 80 bytes per 5 seconds equals 16 bytes per second. Multiplying by 8 bits per byte yields 128 bits per second, or 128 bps. This modest bandwidth illustrates why RTCP traffic is generally negligible compared with the media payload.

📖 Explanation: When symbols alternate, run lengths are all equal to one, so run‑length coding cannot reduce size. Uniform data with long runs, however, compresses well because each run can be represented by a single count‑symbol pair, leading to higher compression ratios.

📖 Explanation: Jitter introduces variability in packet arrival times, which can cause the receiver to misinterpret timing information and report inaccurate jitter or loss metrics. Consequently, the statistical feedback sent to the sender becomes less reliable for precise adaptation decisions.

📖 Explanation: Cumulative fields (e.g., total packets lost) accumulate values from the start of the session, providing a long‑term view. Interval fields, by contrast, reflect changes since the previous report, allowing the sender to see recent trends without the weight of historic data.

📖 Explanation: Run‑length encoding processes each input symbol exactly once, performing only simple count increments and output writes. Therefore the computational cost remains essentially constant irrespective of how much compression is achieved, making CPU usage largely independent of the resulting ratio.

📖 Explanation: The ten consecutive B characters form a single run of length ten, which is represented as the count followed by the symbol: \10B\. This compact form replaces the original ten‑character sequence with a four‑character code, illustrating RLE’s effectiveness on uniform data.

📖 Explanation: Receiver reports convey loss, jitter, and round‑trip metrics. When loss rises above a predefined level (e.g., 2 %), the sender can reduce the video bitrate to improve delivery reliability. This closed‑loop feedback enables dynamic adaptation based on real‑time network conditions.

📖 Explanation: A compound RTCP packet aggregates several individual RTCP report items—such as sender reports, receiver reports, and source description items—into one UDP datagram. This bundling reduces header overhead and ensures that related control information is delivered together.

📖 Explanation: The RTCP specification limits each report packet to at most 31 report blocks, each describing a different synchronization source (SSRC). This bound balances the need to convey information about many participants while keeping packet size manageable for typical network MTUs.

📖 Explanation: The original size of 16 bytes reduced to 10 bytes yields 16 ÷ 10 = 1.6, which is near the integer value 2. Describing the ratio as “almost 2” emphasizes that the compressed data is roughly half the original size, a convenient mental benchmark.

📖 Explanation: Each participant generates its own RTCP reports at the fixed interval. Doubling the participant count therefore doubles the total number of reports transmitted per unit time, leading to a proportional increase in the aggregate RTCP control‑traffic bandwidth.

📖 Explanation: When data changes frequently, the length of each run is typically one or two symbols, so the overhead of storing count‑symbol pairs outweighs any size reduction. Arithmetic coding, by contrast, can assign fractional probabilities to symbols, achieving compression even when runs are absent.

📖 Explanation: A short interval forces each participant to send RTCP reports more often. In a conference with many participants, the cumulative control traffic can approach or exceed the available bandwidth, causing packet collisions, increased latency, and overall congestion that degrades media delivery.

📖 Explanation: Applying delta encoding first captures frame‑to‑frame differences, often producing many small runs of zeros. Subsequent run‑length encoding then efficiently compresses those zero runs, yielding higher overall compression while keeping each step simple and computationally lightweight.

📖 Explanation: Including the NTP timestamp in the RTCP sender report allows the receiver to compare the sender’s wall‑clock time with its own NTP‑synchronized clock, enabling accurate round‑trip time calculations and precise synchronization of media streams across disparate devices.

📖 Explanation: A closed‑loop controller monitors loss reported in RTCP receiver reports; when loss surpasses the 1 % threshold, the controller reduces the transmission bitrate or adjusts encoding parameters, thereby lowering congestion and bringing loss back under the target level.