AS = https://en.wikipedia.org/wiki/Autonomous_system_(Internet)

IX = https://en.wikipedia.org/wiki/Internet_exchange_point

But seriously, reading how the internet works is pretty amazing.

This is hacker news, I think someone can be forgiven for using hacker lingo.

See: How I feel every time someone talks about using some six week old framework to program in some 3 month old extension to some 6 month old language (except, this lingo has been around for decades).

It's ISP / Network Engineer / Bit-shifter Lingo.

AS - Autonomous System (Number, sometimes called ASN). What big networks like ISPs use to identify themselves and route to each other, usually via BGP.

It's a fancy way of saying the parent runs a "mid-sized" network big enough to have an AS, likely a mid-sized regional ISP, or part of a larger ISP.

IX -- Internet Exchange, similar to IBX or DC. Essentially the building where there are routers and switches that connect the networks to each other.

Basically parent is saying that they're an ISP and their systems in the IX that route to Youtube saw a dip in traffic, implying a network event of some sort on the Youtube side.