Overview of Computer Network Basics

Overview of Computer Network Basics

Chapter 2 Overview

1. Understand the two main functions that computer networks provide to users: connectivity and sharing.

2. In conjunction with "4.2.1 virtual Interconnect Network" (p110), understand that "the Internet is a network ".

3. Understand the three phases of Internet development. Arpanet, three-level Internet, and multi-level ISP Internet.

4. Understand Internet standardization and RFC concepts.

5. Understand the composition of the Internet: edge part (resource subnet) and core part (Communication Subnet ).

6. Understand the two communication modes of the resource subnet: Client Server (C/S) and peer-to-peer connection (P2P ).

7. Understand the three exchange methods and focusMasterGroup Exchange (technology, principles, advantages and disadvantages)P12-15, Combined with Figure 1-12 (p15)MasterThe main differences between the three types of exchangesP15.

8. Understand the definition of computer networks and the different types of networksP17-18.

9,MasterKey indicators of Computer Network PerformanceMasterThree Concepts of latency and calculation, understanding the relationship between total latency of data transmission, and understanding RTT.P18-22

10. Understand the formation of computer network architecture and the necessity of adopting Layered thinking.

11. Understand the concept and composition of network protocols.

12. Understand the "error control", "Traffic Control", "segmentation and reinstallation", "reuse and reuse", and "connection establishment and release" functions required at each layer of the network architecture. (concept, what levels of TCP/IP implementation, and how to implement it ).P2

13,MasterKey points of the five-layer protocol network architecture and the functions of each layer.P27-29

14. Diagram 1-17 (p29)MasterData transmission between layers.P29-30

15. Understand PDU, protocol stack, peer layer, and other concepts.

16. Understand the differences and connections between protocols and services.P30-31

17. Understand and understand the idea of everythingover IP and IP overeverything in TCP/IP architecture in combination with Figure 1-21 (p32.P32

Review reference: P33--2, 3, 8, 13, 14,17,18, 19, 21, 22,24,26, 27

 

Chapter 2 Physical Layer

1. Understand the main tasks of the physical layer.

2. Understand the data communication system model.P36-37

3. Understand concepts such as numbers, simulations, data, and signals.

4. Understand the concept of channel, baseband, and width, and the information interaction between communication parties.

5. Understand the functions of the tuner and modem and the three basic modulation methods.SpO2

6. Understand the maximum bitrate of a channel (Nai's criteria) and the maximum transfer rate of the channel (Shannon formula), and understand the differences and connections between the bitrate and the bitrate.P39-40

7. Learn about common transmission media.

8. MasterFrequency division multiplexing and time division multiplexing (synchronous and asynchronous Time Division)P47-50To understand wavelength division multiplexing and code division multiplexing.P52 CDMA

9. Understand digital transmission systems and common broadband access technologies.

 

Review reference: P61--1, 3,46,7, 10,13, 14,16

 

Chapter 2 data link layer

1. Understand the two types of channels used by the data link layer.

2. Understand the concepts of links and data links.

3. MasterEncapsulated into frames (Figure 3-4 (P66), Figure 3-5 (P66), figure 3-10 (P73)), Transparent transmission (byte filling-Figure 3-7 (p61), zero-bit filling-Figure 3-11 (P74), Error detection (CRC principle-Figure 3-8 (P68.(How to judge if the data is changed during transmission. P69)

4. Understand common protocols (PPP) on point-to-point channels ).

5. Understand the characteristics of LAN and common network topology.

6. understand various media sharing technologies (focusing on the technologies for solving collisions during random access ).

7,Understanding two ethernet standards and further layers of the data link layer by the IEEE 802 committee. The function of the adapter. P77-79.

8. Learn about Manchester encoding.

9. Combined with Figure 3-17 (p81)MasterCSMA/CD Protocol (Key Words: Multi-Point Access, carrier monitoring, collision detection), concept of contention period and truncation Binary Index backoff algorithm.P79-83

10. Learn the minimum valid frame length and setting basis stipulated by Ethernet.

11. See figure 3-20 (p85) to learn how the hub works (features ).

12. Understand MAC addresses (functions, storage locations, management allocation methods, lengths, and broadcast addresses) and concepts of unicast, broadcast, and multicasting.P86-89

13,MasterThe frame format of Ethernet V2, to learn the difference between it and 802.3 frame format.P89-90

14. Understand the limitations of LAN extension on the physical layer.

15. Understand the concepts of conflicting domains (P92) and broadcast domains (areas covered by broadcast frames) (search by Internet ).

16. Diagram 3-28 (P95)MasterAfter a frame is received by a transparent bridge (switch ),Learning-- Learn how to add the forwarding record to the forwarding table based on the target addressForwarding)P94-96. Learn about the Spanning Tree Algorithm.

17. Learn about virtual LAN and high-speed Ethernet.

 

Review reference: P105--1, 4,7, 8, 9, 10, 15, 18, 20, 28, 31,32, 33

 

Chapter 2 Network Layer

1. See Figure 4-1 (P109) And Table 4-1 (p109) understand the virtual circuit service and datagram service.

2. See Figure 4-2 (P110) Understand common network layer protocols in TCP/IP architecture and their functions.

3. Understand "virtual Interconnection Network" (commonly used network interconnection equipment) in conjunction with "1.2.1 network" (P2)P111).

4. See Figure 4-4 (P112) Understand direct delivery and indirect delivery.

5. Understand IP addresses (function, length, classification address, point-to-decimal notation, assignment range of classification addresses, Special IP addresses, features, and precautions ), understand the differences between IP addresses and hardware addresses (see Figure 4-10 (P118) And Table 4-4 (P118)MasterTransmission process of an IP packet-the hardware address transformation process of data frames on each link during encapsulation and encapsulation ).

6. See Figure 4-12 (P120)MasterThe role and principle of ARP.

7,MasterIP datagram format (Unit of the header length, related fields and methods of the shard-Figure 4-14 (P124) And Table 4-5 (P124), The Role and processing method of the survival time, the role of the Protocol field, and the calculation of the checksum -- Figure 4-15 (P125), And consider which fields of the IP packet header will be modified when the router forwards an IPv4 packet ).

8. diagram 4-16 (P126), Figure 4-17 (P127)MasterThe IP layer forwarding group process (that is, the group forwarding algorithm) to understand the concept and role of default routing.

9,MasterThe concept of subnet division and the role of subnet mask-Figure 4-20 (P131), Figure 4-21 (P132), Table 4-6 (P132)Example 4-2 (Psung), Example 4-3 (P4); examples 4-4 (P134)MasterForward packets when using subnets; understand the characteristics of CIDR, the record method, and the longest prefix Matching PrincipleP135-139.

10. Understand ICMP protocol types, common types, and principles of common applications (Ping and traceroute ).

11. Understand the classification of routing algorithms (Static Routing and Dynamic Routing), the classification of dynamic routing protocols, and common routing protocols (Chinese names and abbreviations ).

12. ComparisonMasterThree key points of RIP and OSPF. Examples 4-5 (P149)MasterDistance Vector Algorithm; combined with Figure 4-33 (P151) Understand the slow propagation of RIP bad messages.

13. Understand the structure of a vro in combination with Fig 4-42 (p160), Fig 4-43 (p162), and Fig 4-44 (p162.

14. Understand the concept of multicast, the role of VPN, and the role of Nat.

 

Review reference: P175--1, 3, 4,5, 6, 7, 9, 10, 15,20, 21, 22, 23,26,31, 34,39,41, 42

 

Chapter 2 Transport Layer

1. Understand the reuse and reuse functions of the transport layer and the concept of port.

2,MasterUDP Header FormatP184-186.

3. Understand the main characteristics of TCP and TCP connections.

4. See Figure 5-9 (P190), Figure 5-10 (P191) Understand the Stop wait protocol. See Figure 5-13 (P193) Understand the continuous ARQ protocol.

5,MasterTCP Header Format.P193-195

6. See Figure 5-15 (P197), Figure 5-16 (P198), Figure 5-18 (P199), Figure 5-19 (P200) Understand the sliding window in bytesP197-200)Use the formula 5-4, 5-5, and 5-6 to understand the selection mechanism of the timeout retransmission time.(P201).

7. Figure 5-22MasterTCP traffic control mechanism. (P203-204)

8. Combined with Figure 5-24, Figure 5-25, Figure 5-26, and figure 5-27MasterTCP congestion control mechanism (concept of congestion window, slow start threshold, slow start algorithm, congestion avoidance algorithm, fast retransmission algorithm, and fast recovery algorithm ).P207-P212)

9. Understand TCP transport connection management in combination with Figure 5-31 (p216) and figure 5-32 (p217.P215-218)

 

Review reference: P--3,4, 6, 8, 9,11, 12, 13, 14, 17, 18, 23, 26, 28,34, 37, 38, 39, 41

 

Chapter 2 Application Layer

1. Understand the basic concepts and domain name structure of DNS.

2. Understand how domain name Conversion Works (recursive and iterative query processes ).

3. Understand how FTP works (two TCP connections: control connections and data connections ).

4. Understand the remote terminal protocol Telnet.

5. Understand how the world wide web works and HTTP operations.

6. Understand the principles and operations of email.

7. Understand the concept of DHCP.

8. Understand the Simple Network Management Protocol SNMP.

 

Review reference: P280--2, 3, 5, 7, 8, 10, 19, 20, 22, 23, 24, 32, 33