It is obviously desired for the latency to remain as close to 0 as possible, however, there may be a few things that lead to higher latency times. Let us see some of these:
Distance: One of the major causes of the network latency is distance, to be more specific it is the distance between the client devices that make requests and the servers that respond to those requests.
To understand this let us consider an example i.e. a website hosted at a data center in Columbus, Ohio would give a quicker response within 10-15ms to the requests made by the users in Cincinnati that is 100 miles away as compared to the users in Los Angeles which is 2200 miles away and comes across longer delays i.e. about 50ms.
The farther you are from the ISP, Hub, satellite connection the longer it takes for the information to be transferred.
Congestion: This is similar to the bandwidth i.e. the smaller is your bandwidth connection the more is the network congestion i.e. you experience slower Internet with low latency.
An increase in few milliseconds of latency measure may not seem to be much but it is constituted by all the back and forth communication important for both the server and client to establish a connection, any issue with the network equipment through which the data passes and the total size and the load time of the page.
When the client places request the amount of time required for the response reach a client device is called as the RTT or round trip time.
Internet Exchange Points (IXPs): Data traversing across the internet generally crosses not only one but multiple networks. The more the number of networks that the HTTP response has to pass through, the more is the chance of delay.
For Example: When the data packets traverse through the networks, they pass via Internet Exchange Points i.e. IXPs. There, the routers need to process and route the data packets and at times the routers may need to break those into smaller packets, and all of these add some milliseconds to RTT.
The Webpage Construction
The slower performance sometimes is also due to the way the webpages have been constructed. Some of the web pages are featured with an increased amount of heavy content or even load content from several third parties might show a sluggish performance, as in this case the browsers are required to download larger files to display those.