A network layer is not needed if both the hosts are in the same network. A data link layer can be used in such cases.
ICMP The Internet Message Protocol (ICMP) allows hosts to exchange messages to indicate the status of a packet as it travels through the network.
tcp
the geographic scope of the network the physical layer implementation the number of hosts to be interconnected
A proprietary network protocol is one that does not comply to any open standards. The intent of a proprietary protocol is to limit communication only to nodes that implement a specific application. NetBIOS is an example of a proprietary network protocol that is only applicable to Microsoft Windows hosts. The opposite of a proprietary protocol is an open standard, which can be utilized by any application. An example of an open standard is TCP/IP, the standard protocol of the Internet.
-The geographic scope of the network -The physical layer implementation -The number of hosts to be interconnected
Border Gateway Protocol (BGP) is a way to transfer data and information between different hosts such the Internet or routers. It is commonly used between Internet Service Providers (ISPs).
The most common two are TCP (transmission control protocol) and UDP (user datagram protocol)
UDP
255.255.252.0
ARP
255.255.252.0
255.255.252.0