2.4 Network Architecture: Emails

2.4  Network Architecture: Emails

TCP/IP is an end-to-end network. Figure 2.21 shows TCP/IP Mail system architecture where user A can read, write, send and receive an email directly from internet mail server to the user B and vice versa. Both computers of user A and user B connected from its Network Interface Card through the internet router to the internet. The data flow from each email client to the email server is the same as TCP/IP operation in Chapter 2.1.3.

Figure 2.21: Internet Mail

Figure 2.22 shows DTN Mail system architecture where there is a separate networking environment which is an offline local area network and internet connected network. There are mail servers on both sides which act as a storage for email system. The storage in between that used to forward the data is called infomediary device.

Figure 2.22: DTN Mail

The DTN architecture aims to provide interconnection between several networks which may have a network disruption because of distance or time delay in data transmission. DTN user communicates through a DTN network to the internet user, while TCP/IP had the direct connection to the internet. Each network station requires one DTN mail server for temporary storage while TCP/IP does not need a local server and had a direct connection to various internet mail servers. A DTN network requires an infomediary device to transfer and receive data between network stations while TCP/IP does not need it.