Which IP SLA operation is most commonly used to measure network performance parameters such as jitter, latency, and packet loss for real-time applications?
Correct Answer: B
Detailed Explanation: IP Service Level Agreements (IP SLA) is a Cisco feature that allows network administrators to actively measure network performance parameters in real time. These performance metrics include round-trip time, jitter, packet loss, and latency. Such measurements are critical for assessing the quality of service (QoS) provided by a network, especially for delay-sensitive and real-time applications like VoIP and video conferencing. The UDP Jitter operation is specifically designed to evaluate the quality of network paths by sending a stream of UDP packets between devices and measuring the delay variation (jitter), latency, and packet loss. Here’s how it works: Packet Exchange: The source device sends UDP packets to a target device at a specified rate. These packets typically contain a sequence number and a timestamp. Measurement of Latency and Jitter: The target device receives the UDP packets and, if configured for two-way operations, sends a response back to the source device. The source then calculates the round-trip time (RTT) for each packet exchange. Jitter is measured as the variation in delay between packets over the session. Packet Loss Detection: By analyzing the sequence numbers, the IP SLA operation can determine whether any packets were lost during transit. Reporting: The collected data is then summarized, providing valuable insights into network performance. This information can be used for troubleshooting, verifying QoS configurations, and making decisions about network design or upgrades. Comparison with Other Options: ICMP Echo (Option A): While the ICMP Echo operation (commonly used by the “ping” command) measures round-trip time, it does not provide detailed metrics such as jitter or packet loss, which are critical for assessing real-time application performance. TCP Connect (Option C): The TCP Connect operation measures the time to establish a TCP connection, which is useful for assessing application response time, but it is not specifically tailored for measuring jitter and packet loss. HTTP GET (Option D): The HTTP GET operation can be used to measure the performance of web servers and the network paths to them, but it is not designed to measure the granular performance metrics (like jitter and latency variation) needed for real-time applications. Why UDP Jitter is Ideal: UDP is a connectionless protocol that introduces minimal overhead, making it well-suited for performance measurements. The UDP Jitter operation simulates the behavior of real-time applications that often use UDP (e.g., VoIP), providing a realistic picture of how the network will perform under actual load conditions. The detailed metrics gathered by UDP Jitter allow network engineers to fine-tune QoS settings and identify problematic segments in the network that may be contributing to performance degradation. Conclusion: For measuring network performance parameters critical to real-time applications, the UDP Jitter operation (Option B) is the most appropriate and commonly used IP SLA operation. Mastering IP SLA and its various operation types is an important skill for network professionals tasked with ensuring that network performance meets the stringent requirements of modern, high-demand applications.
This CCNA practice question helps students prepare for Cisco networking certification exams by testing knowledge of network fundamentals, routing, switching, and network security concepts.