Networking Foundations
Ric Messier · 2019
This chapter focuses on the importance of networking technologies and communications protocols. It also discusses the Open Systems Interconnection (OSI) model and the TCP/IP architecture. One common approach to providing information technology services in companies, especially if the services are to external users or customers, is to use service providers. Cloud computing can be used as an implementation of this type of outsourcing. Making use of these service providers and working with organizations that have placed systems and services with them introduces some specific challenges to someone performing security assessments or penetration tests. This means that understanding how these external service providers work can be essential. The TCP/IP architecture is a much simpler design than the OSI model, which is an immediate difference and a reflection of the as-built nature of the design as compared with the conceptual design of the OSI. Since the OSI model had to be abstract and flexible in order to accommodate a wide variety of protocols and designs, it was broken out into the seven functional categories described earlier. TCP/IP, on the other hand, as an as-built definition, is only four layers. This is not to say that there is no correlation between the OSI model and the TCP/IP architecture.