Port speed and Modem speed are terms that an average IT worker comes across regularly. But, what is the difference between the two? In simple words, the speed at which a router communicates with a modem is known as the modem speed, Port speed on the other hand is the speed with which a router communicates with the people connected to its local network.
The difference is very similar to that of a water connection. Imagine that your tap is connected to a main pipe. The main pipe would be able to carry a large volume of water while the tap at your home can only deliver few gallons/litres per minute. Here, the capacity of main pipe is similar to that of port speed and that of the tap is similar to modem speed.
Port speed and modem speed are important factors as far as you are concerned with website performance. Lower speeds can restrict usability and browser loading, slowing external and internal traffic. If you know how to measure both, it can be helpful in identifying routers that are slowing your business website.
This is a measure of the external communication of a router with a modem. It is important because there are routers that are allowed to communicate with other external clients. Such connections are usually slower than local Ethernet connections. Due to this, the modem speed of a router might be very low compared to its own port speed. This happens even if the same Ethernet version used to communicate with other network devices are used for modem communication.
Ethernet interfaces are generally used by wired routers for local device communication. The speed of transmission and reception of data by these interfaces is termed port speed. There are two key factors affecting port speed – Ethernet version in use and transmission speed from its clients. As Ethernet standards have evolved, there are standards such as Gigabit Ethernet which detect and intelligently vary their speeds according to the capability of a device they are communicating with.
As there are differences between port speed and modem speed, there are huge variations in network traffic speeds depending on where they originate and where they reach. For instance, you have 8 PCs on a 1Gbps Ethernet connection with 50Mbps cables, the PCs will communicate with each other at a rate of 1Gbps while the traffic from the internet would be at 50Mbps. Thus, the restricted modem interface speed sets a limitation for traffic arriving from elsewhere.
Test the transfer speed of your router
This is a fairly simple process. Just open your browser, go to speedtest.net. You can see a button that says ‘Start Test’. Click on that and wait for the test to get completed. Once complete, you can look at the numbers given under the download speed and upload speed labels. You just need to compare these numbers to the ones that was advertised for your connection by your ISP.