In studying network engineering, it is usually taught that network engineers are responsible from physical layer up to transport layer, that is, layer 1-4 only.
Obviously, HTTP or HTTPS are off-topic within network engineering. But things like BGP, RIP, DNS, DHCP, HSRP, GLBP, OpenFlow, OpenVPN, etc., which are application layer protocols, are definitely handled by network engineers (developers don't care about these stuffs, and they don't have to).
So in general, what do we call those application layer protocols that are within the scope of network engineering?
Alternatively, in general what application layer protocols are out of scope of network engineering?