[bobblywobbles]

Can someone please explain to me the POP reference? I do not understand what this author means by that.

I also would like help understanding what $ units gives? The command looks to be "units", but where do the numbers he entered in come from? I would appreciate this extra context.

[sonofgod]

$ is the shell prompt; he's not typing it. "3 millilightseconds" is the distance light travels in 3 milliseconds, the time a "zero" timeout would take to actually timeout. (This comes directly from the definition of the lightsecond: how far light travels in one second) "miles" is what he wants to see that distance converted to. Turns out it's 558 miles; one mile is 0.00179 of 3 millilightseconds.

[yousifa]

Point Of Presence (POP) is the location where two or more networks meet each other to connect.

Here is a good explanation: https://blog.stackpath.com/point-of-presence/

[dahfizz]

Point of Presence is where the university network would connect with the internet

[sonofgod]

POP I believe is "point of presence"; I believe its meaning is "the point at which our network connects to the internet".