Soft exam review-basic network knowledge

1. networks with different transmission distances can be divided into LAN, man, and wan.

2. Classified by working mode, which can be divided into peer-to-peer network and server-based network

3. Composition of computer networks

1. Server

2. Workstation

3. Road of signals-transmission media

1) coaxial cable:

Fine coaxial cable rg58: Suitable for creating the simplest and most small workgroup-level small network at the lowest price

Coarse coaxial cable rg11

2) twisted pair wires:

Unshielded twisted pair UTP: Applicable to LAN cabling. You can select 5 or 6 lines as needed.

Shielded twisted pair Cable STP

3) optical fiber:

Single-Mode Optical Fiber: Suitable for networks with high transmission requirements, or as the backbone network or high-speed wide-area connections

Dual-mode optical fiber: Used in networks with high transmission requirements and suitable for wide-area connections

4) radio waves

5) microwave

6) infrared

7) Laser

4. Computer whistle card-nic

5. Modem

6. repeater and hub

All work in the Physical Layer

7. inter-network checkpoints-bridges, routers, and gateways

Bridge: supports frame filtering.

Router: connect two different types of LAN

Gateway: working at the network layer

8. vswitch

Layer 2 Switch: a device that works on the data link layer and is used to replace a hub in a small network.

Layer-3 Switch: working at the network layer, which completes some or all functions of a common Router

High-rise switches: Work on the network layer. They can implement some special functions based on the functions of common routers.

9. standards and protocols

Concept framework: OSI network layer protocol

Fact standards: the cornerstone of the Internet TCP/IP protocol family, Windows Lan standard NETBIOS, NetWare network standard SPX/IPX protocol family

4. network protocols and standards

1. OSI (Development System Interconnection Reference Model)

7) Application Layer)

6) presentation layer (presentation)

5) Session Layer)
4) Transport)
3) Network)
2) Data Link)
1) physical layer (physical)

1) OSI:

It is only a communication framework and does not play a role in the specific communication process.

2) Physical Layer:

It is completely hardware-oriented and defines the mechanical, electrical, functional, and procedural features of communication equipment through a series of protocols.

3) data link layer:

Encapsulated into frames: data is made up of data blocks of a certain size, which is called frames.

Traffic control:

Error Control

Transmission Management

4) IEEE802 Specification

802.1: 802 introduction to Protocols

802.2: Logical Link Control Layer (LLC) Protocol

802.3: CSMA/CD over Ethernet (Multi-Channel Access/conflict detection for carrier listeners) Protocol

802.4: Token Bus Protocol

802.5: Token Ring Protocol

802.6: Man Protocol

802.7: Broadband technical agreement

802.8: Optical Fiber Technology Agreement

802.9: Lan speech/Data Integration specifications

802.10: LAN security interoperability standard

802.11: standard protocol for wireless LAN (WLAN)

5) Network Layer

Protocols that work at the network layer mainly include IP protocol and IPX protocol.

6) Transport Layer

The protocols used at the transport layer include TCP, UDP, and SPX. Both TCP and UDP belong to the TCP/IP protocol family.

7) Session Layer

Communication Control; checkpoint settings; re-build interrupted transmission links; Name Search and security verification services

8) Presentation Layer

Data Encoding conventions; conversion of local syntaxes

Protocols that indicate data formats also belong to the presentation layer, such as MPEG and JPEG.

9 Application Layer

Interfaces of various application processes; user interfaces