While Functional Testing includes negative testing, conformance testing, interoperability testing, etc.
Stress and Reliability tests cover Load Testing, Stress Testing, Performance Testing, etc. Stress and Reliability Tests and Functional Tests. Protocol testing can be segregated into two categories. Bandwidth: How many packets we can send per second.Latency: How long does a packet take to transit the system.
During protocol testing basically, three checks are done. Protocol testing includes testing of functionality, performance, protocol stack, interoperability, etc. of the device by using tools like lxNetworks, Scapy and Wireshark While simulator simulates various entities of networking element Mac address, Ethernet, Token Ring, and Frame Relay are all examples of Data link layer.