Relevant protocols for the stream inspector

The relevant protocols that are processed by a stream inspector are Internet Protocol (IP), User Datagram Protocol (UDP), Internet Control Message Protocol (ICMP), and Transmission Control Protocol (TCP). In this section, we will discuss some basics regarding these protocols. If you are well-versed in the details of the IP, ICMP, TCP, and UDP protocols, feel free to skip this section.

IP

Of these protocols, IP is a layer 3 (network layer) protocol according to the OSI model. This protocol deals with the delivery of network datagrams from a source to a destination, as specified in the IP header. The protocol follows a best-effort strategy, in which there is no guarantee that the datagram will reach the destination, or that the datagram will reach the destination error-free. If a source sends several datagrams to a particular destination using IP, there is no guarantee that all the datagrams will go via the same route (unless certain...