What is round-trip time?

Round-trip time (RTT) refers to the duration, measured in milliseconds (ms), that it takes for a network request to travel from its starting point to a destination and then return back to the starting point. RTT serves as a crucial metric for assessing the performance and reliability of network connections, both within local networks and across the broader Internet. Network administrators commonly employ RTT to diagnose connection speed and dependability.

One of the primary objectives of a Content Delivery Network (CDN) is to minimize RTT. This can be achieved by reducing latency, which can be measured by the decrease in round-trip time or by eliminating the need for roundtrips altogether. For instance, modifying the standard TLS/SSL handshake can help in reducing the instances where roundtrips are necessary.

The ping utility, which is available on almost all computers, is a commonly used method to estimate round-trip time. Let’s consider an example of pinging Google, where the round-trip time for each ping is calculated and displayed at the bottom. It is worth noting that one of the ping times, specifically 17.604ms, stands out as being higher than the rest.

How does round-trip time work?

Round-trip time, also known as RTT, represents the duration required for data to travel to a destination and return back. Drawing from the knowledge shared about the benefits of CDN latency, let’s consider a scenario where a user in New York wishes to communicate with a server located in Singapore.

When the user in New York initiates the request, the network traffic traverses through numerous routers situated in different physical locations before reaching its final destination—the server in Singapore. Subsequently, the server in Singapore transmits a response back over the Internet to the original location in New York. Once the request arrives in New York, we can approximate the time it takes for the entire round trip between these two locations.

It’s important to note that round-trip time serves as an estimate and not a definitive guarantee. The route between the two locations can vary over time, and other factors such as network congestion can impact the overall transit duration. Nevertheless, RTT plays a crucial role in assessing the feasibility of establishing a connection and provides a rough estimate of the time required for the journey.

What are the common factors that affect RTT?

RTT, or Round-Trip Time, can be influenced by various factors, including infrastructure components, network traffic, and physical distance between the source and destination. Here is a list of factors that can affect RTT:

• Transmission medium: The type of connection used, such as optical fiber, copper, wireless, or satellite communication, can impact how quickly data travels. Each medium has its own characteristics, affecting the speed and latency of the connection.

• Local area network (LAN) traffic: The volume of traffic within a local network can cause congestion and limit the connection’s performance before it even reaches the wider internet. For instance, simultaneous streaming of videos by many users on the LAN can hinder the round-trip time, even if the external network has sufficient capacity.

• Server response time: The time taken by a server to process and respond to a request can act as a potential bottleneck in network latency. When a server is overloaded with requests, like, during a DDoS attack, its ability to respond efficiently decreases, resulting in increased RTT.

• Node count and congestion: The path that a connection takes across the internet can involve traversing different intermediate nodes or hops. Generally, the more nodes involved, the slower the connection becomes. Additionally, network congestion at specific nodes due to other traffic can further slow down the connection and increase RTT.

• Physical distance: Although content delivery networks (CDNs) can optimize connections by reducing the number of hops, the speed of light still imposes limitations. The distance between the starting and ending points of a connection affects network connectivity and cannot be entirely overcome. However, CDNs can mitigate this obstacle by caching content closer to users, thereby reducing RTT.

In summary, RTT can be influenced by factors such as the transmission medium, LAN traffic, server response time, node count and congestion, and physical distance. Understanding these factors helps in identifying and addressing latency issues for improved network performance.

How can a CDN improve RTT?

By strategically situating servers within internet exchange points and cultivating strong partnerships with Internet service providers and network carriers, a content delivery network (CDN) effectively enhances network pathways between various locations. This optimization process leads to decreased round-trip time (RTT) and enhanced latency for users accessing cached content within the CDN.

Delve into the lesson on CDN performance to gain insights into how caching, strategically locating data centers, minimizing file sizes, and implementing other optimization techniques contribute to latency reduction and improved RTT. Acquire knowledge on how the utilization of Toffs CDN specifically enhances RTT.