1. Rules Of Communications
1.1. The Rules
1.1.1. Message encoding adalah Salah satu langkah pertama untuk mengirim pesan adalah pengkodean. Encoding adalah proses mengubah informasi menjadi bentuk lain yang dapat diterima, untuk transmisi. Decoding membalik proses ini untuk menafsirkan informasi.
2. 3.2 Network Protocols and Standards
2.1. 3.2.1 Protocols
2.1.1. 3.2.1.1 Rules that Govern Communications
2.1.1.1. Salah satu cara terbaik untuk memvisualisasikan bagaimana protokol dalam sebuah suite berinteraksi adalah dengan melihat interaksi sebagai tumpukan. Tumpukan protokol menunjukkan bagaimana masing-masing protokol dalam sebuah suite diimplementasikan.
2.1.1.2. 3.2.1.2 Network Protocols
2.1.1.2.1. Network Protocols Pada tingkat manusia, beberapa peraturan komunikasi bersifat formal dan yang lainnya hanya dipahami berdasarkan kebiasaan dan praktik. Agar perangkat berhasil berkomunikasi, suite protokol jaringan harus menjelaskan persyaratan dan interaksi yang tepat. Protokol jaringan mendefinisikan format umum dan serangkaian aturan untuk bertukar pesan antar perangkat. Beberapa protokol jaringan yang umum adalah Hypertext Transfer Protocol (HTTP), Transmission Control Protocol (TCP), dan Internet Protocol (IP).
2.1.1.2.2. 3.2.1.3 Protocol Interaction
3. 3.2.3 Standard Organizations
3.1. 3.2.3.1 Open Standards
3.1.1. Open Standards Open standards encourage interoperability, competition, and innovation. They also guarantee that no single company’s product can monopolize the market, or have an unfair advantage over its competition. A good example of this is when purchasing a wireless router for the home. There are many different choices available from a variety of vendors, all of which incorporate standard protocols such as IPv4, DHCP, 802.3 (Ethernet), and 802.11 (Wireless LAN).
3.2. 3.2.3.2 Internet Standards
3.2.1. Internet Standards Standards organizations are usually vendor-neutral, non-profit institutions established to develop and promote the concept of open standards. Various organizations have different responsibilities for promoting and creating standards for the TCP/IP protocol.
3.3. 3.2.3.3 Electronics and Communications Standard Organizations
3.3.1. Other standard organizations have responsibilities for promoting and creating the electronic and communication standards used to deliver the IP packets as electronic signals over a wired or wireless medium
3.4. 3.2.3.4 Lab - Researching Networking Standards
3.5. 3.2.4 Reference Model
3.5.1. 3.2.4.1 The Benefits of Using a Layered Model
3.5.1.1. The Benefits of Using a Layered Model The benefits to using a layered model to describe network protocols and operations include: Assisting in protocol design because protocols that operate at a specific layer have defined information that they act upon and a defined interface to the layers above and below. Fostering competition because products from different vendors can work together. Preventing technology or capability changes in one layer from affecting other layers above and below. Providing a common language to describe networking functions and capabilities.
3.6. 3.2.4.2 The OSI Reference Model
3.6.1. 3.2.4.3 The TCP/IP Protocol Model
3.6.1.1. 3.2.4.4 OSI Model and TCP/IP Model Comparison
3.6.1.1.1. Reference Models 3.2.4.5 Activity - Identify Layers and Functions
3.6.1.2. The TCP/IP Protocol Model The TCP/IP protocol model for internetwork communications was created in the early 1970s and is sometimes referred to as the Internet model. As shown in the figure, it defines four categories of functions that must occur for communications to be successful. The architecture of the TCP/IP protocol suite follows the structure of this model. Because of this, the Internet model is commonly referred to as the TCP/IP model.
3.6.2. The OSI Reference Model The OSI model provides an extensive list of functions and services that can occur at each layer. It also describes the interaction of each layer with the layers directly above and below. The TCP/IP protocols discussed in this course are structured around both the OSI and TCP/IP models. Click each layer of the OSI model to view the details.
4. 3.3 Data Transfer in the Network
4.1. Message Segmentation In theory, a single communication, such as a music video or an email message, could be sent across a network from a source to a destination as one massive, uninterrupted stream of bits. If messages were actually transmitted in this manner, it would mean that no other device would be able to send or receive messages on the same network while this data transfer was in progress. These large streams of data would result in significant delays. Further, if a link in the interconnected network infrastructure failed during the transmission, the complete message would be lost and have to be retransmitted in full.
4.2. 3.3.1 Data Encapsulation
4.2.1. Encapsulation Example When sending messages on a network, the encapsulation process works from top to bottom. At each layer, the upper layer information is considered data within the encapsulated protocol. For example, the TCP segment is considered data within the IP packet. Click Play in the figure to see the encapsulation process as a web server sends a web page to a web client.
4.2.2. De-encapsulation This process is reversed at the receiving host, and is known as de-encapsulation. De-encapsulation is the process used by a receiving device to remove one or more of the protocol headers. The data is de-encapsulated as it moves up the stack toward the end-user application. Click Play in the figure to see the de-encapsulation process.
5. 3.4 Summary
5.1. 3.4.1 Conclusion
5.2. Lab - Installing Wireshark Wireshark is a software protocol analyzer, or "packet sniffer" application, used for network troubleshooting, analysis, software and protocol development, and education. Wireshark is used throughout the course to demonstrate network concepts. In this lab, you will download and install Wireshark.
5.2.1. Lab - Using Wireshark to View Network Traffic In this lab, you will use Wireshark to capture and analyze traffic.
5.2.1.1. Class Activity - Guaranteed to Work! You have just completed the Chapter 3 content regarding network protocols and standards. Assuming you resolved the beginning of this chapter’s modeling activity, how would you compare the following steps taken to design a communications system to the networking models used for communications? Establishing a language to communicate Dividing the message into small steps, delivered a little at a time, to facilitate understanding of the problem Checking to see if the data has been delivered fully and correctly Timing needed to ensure quality data communication and delivery