Answer 1

I wouldn't say essential but useful. If you can program in python or any other respectable language it will help you to think more logic.

But the exam is just about OSI layer 1, 2 and 3 and some 4 a bit subnetting here and there some Ethernet standards, IPv4 and IPv6, WAN, NAT, Routing, TCP/IP, Switching, MAC addresses and tables, VLANs Network Classes, IGP and EGP, DNS and DHCP, Access Control and a bunch related stuff.

Good luck!