2. LITERATURE REVIEW

1.      LITERATURE REVIEW

In this chapter, the background to Transmission Control Protocol and Internet Protocol (TCP/IP) and delay and disruption tolerant networking (DTN) presented. The details begin by describing the TCP/IP layers, internet addressing and how TCP/IP works. Then continue by describing the basic problem when using internet protocols and outline the reason to use DTN. After that architecture of DTN is discussed and then the TCP/IP and DTN is compared.

2.1  Transmission Control Protocol and Internet Protocol (TCP/IP)

The Transmission Control Protocol and Internet Protocol (TCP/IP) enable communications across a vast and heterogeneous collection of networks. Transmission Control Protocol (TCP) is a reliable data delivery and connection service protocol. TCP making sure the packet delivery is acknowledged and transmitted as needed.

The TCP/IP offers two basic communication services that operate on top of IP which is Transmission Control Protocol (TCP) and User Datagram Protocol (UDP). There are five main layers in TCP/IP which is Application Layer, Host-to-Host Transport Layer, Network/Internet Layer, Data link/Network Access Layer and Physical Layer [4]. Figure 2.1 shows a TCP/IP Architecture Layers compare against Open Systems Interconnection (OSI) Model Layers. In this comparison, the TCP/IP application layer includes the OSI application layer, presentation layer and session layer. Its Host-to-Host transport layer includes the some part of the OSI session layer and OSI transport layer. The Network/Internet Layer is a subset of the OSI network layer. The Data link/Network Access layer includes the OSI Data link Layer. Physical Layers in TCP/IP and OSI Model is on the same level. Mostly TCP/IP Physical Layer is included in Data link/Network Access layer and also called Network Interface Layer. 

Figure 2.1: TCP/IP Protocol Architecture