Traveling Through a Network

 

Understanding the path packets travel through a network is crucial for network administrators and IT professionals. The ping and traceroute commands are essential tools that provide this insight, allowing us to measure the time it takes for packets to reach their destination and analyze the route they follow.

Ping is a simple network utility that sends packets to a specified host and waits for a reply. This process helps determine whether a particular host is reachable and how long it takes for packets to travel roundtrip between the source and destination. Traceroute, on the other hand, is a useful tool that provides detailed information about the path packets take to reach a destination. When packets with increasing Time To Live (TTL) values are sent, routers along the path will send ICMP Time Exceeded messages in response. Analyzing these messages enables traceroute to map out the path taken by the network from source to destination, helping to understand the network's structure. By comparing ping results from the United States website, google.com, and the Japanese site, docomo.ne.jp, there were some differences in the amount of time packets took to reach their destination as well as the path taken to reach the destination. In the ping tests, each IP address was sent 32 kb packets, and the times they took to reach their destination were recorded. Unsurprisingly, the US-based site Google had a lower average time, but not by much. Only one of the packets sent to docomo.ne.jp took significantly longer, which caused the average to be 20 milliseconds higher. In general, packets traveling shorter distances experience lower latency than those traveling longer distances. This shows a direct relationship: the farther apart two hosts are geographically, the longer it takes for packets to travel between them.

The traceroute results were similar in the packets' arrival times with the international packets taking longer than the domestic ones, as expected. The packets also took different hops to their final destinations, with two timeouts on the Google route and four on the Decomo one. These differences are influenced by many factors, such as network congestion, routing policies of Internet Service Providers (ISPs), geographical location of servers, and network topology.

I have used both utilities in my career as an ISP technician. For example, a customer vocalized that he was experiencing packet loss around certain times of the day. After running a continuous ping around this time on two devices while monitoring the time packets took to arrive and how many packets were lost over time, we were able to identify the problem within our infrastructure (water-damaged equipment). Another time, a traceroute was run to discover that a website was down because it kept timing out of the last few hops. There are many reasons a traceroute or ping command might timeout or return an error. A site can be down, and incorrect network configurations and firewall restrictions are some examples.

Ping Results: 

Trace Route Results: