What is RTT(Round Tip Time)?

Photo by: Harley-Davidson on Unsplash

Round Trip Time(RTT) is the time it takes for a packet to travel back and forth from the source to the destination on the Internet.

RTT is often used to diagnose the speed and safety of network connections.

There are several factors that affect RTT. It affects wireless or wired communication, short-distance or long-distance, and network traffic, etc.

So how do we know RTT? Our common method is to use the ping command.

ping -c 3 www.google.com

The result of above command is like this:

PING www.google.com (172.217.25.164): 56 data bytes
64 bytes from 172.217.25.164: icmp_seq=0 ttl=56 time=33.223 ms
64 bytes from 172.217.25.164: icmp_seq=1 ttl=56 time=39.302 ms
64 bytes from 172.217.25.164: icmp_seq=2 ttl=56 time=40.269 ms

 — - www.google.com ping statistics — -
3 packets transmitted, 3 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 33.223/37.598/40.269/3.119 ms

In the results, Time To Live (TTL) represents the lifetime of the IP packet and is a value within the IP packet.

This is used to prevent packets from being in the network for a long time, each time they pass through the router, the value decreases by 1 and when the value reaches 0, the router drops the packet and sends an ICMP message to the host that sent the packet.

ICMP(Internet Control Message Protocol) is a protocol that notifies if there is a problem when processing IP packets over TCP/IP.

In other words, it is responsible for sending information about errors to the host.

Time literally means the amount of time it took for a packet to come and go.