Does IP provide QoS or not?

IP provides a best-effort delivery service. I believe this implies, among other things, that it offers no QoS to the users.

However, IP has a byte in its headers (ToS in v4 and Trafic Class in v6) that I think does indeed of…

Immediately block a host’s traffic

I’ve got a script set up (triggered by Fail2Ban) to block hosts at the edge of our network. It adds the IP address to a group that’s already blocked by an ACL, and then clears the connection out.

configure terminal
object ne…

Layer 2 ARQ protocols

Some authors (i.e. Tanenbaum, Stallings) reference ARQ protocols as layer 2 mechanisms for handling errors.

Even this page from Wikipedia says that

these protocols reside in the Data Link or Transport Layers

Which ARQ…