①Concept: A local area network is a computer that allows many independent computers Channel directly within the appropriate area and at the appropriate transmission rate Tong data communication system

②Features

①Bus type

②Star shape

③Ring shape

①Physical layer (PHY)

②Media Access Control Layer (MAC)

③Logical link control layer (LLC)

IEEE 882.1 - Overview, architecture and network interconnection, and network management and performance measurement

IEEE 802.2 - Logical link control is the interface between high-level protocols and any LAN MAC sublayer

IEEE802.3 - CSMA/CD, defines the MAC sublayer and physical layer specifications of the CSMA/CD bus network

IEEE 802.4 - Token Bus Network

IEEE 802.5 - Token Ring Network

IEEE 802.6 - Metropolitan Area Network MAN

IEEE 802.7 - Defining Broadband Network Technology

IEEE 802.8 - Defining fiber optic network technology

IEEE802.9 - for integrated voice data LAN

IEEE 802.10 - Defining interoperable local area network security specifications

IEEE 802.11 - Defining wireless LAN standards

IEEE 802.12 - Standard for defining priority high-speed local area networks (100Mbps)

IEEE 882.14——Definition of interactive television network (Cable Modem) standard

IEEE 802.15 - Defining the standard for broadband wireless LAN

static allocation method

Dynamic allocation method

CSMA/CD

Working principle: listen first and then speak, listen and speak at the same time, stop transmitting when conflict occurs

work process

①Server

②Network workstation

③Network adapter

④Switch

⑤Transmission medium

①Network operating system

②Network database management system

③Network application software

①Definition: Peer-to-peer network can also be said to not require a server LAN, which is a distributed network system

②Applicable occasions: small offices, laboratories, etc.

③Features

①Applicable occasions: industrial and commercial enterprise network, campus network, etc.

②Features

advantage

shortcoming

①Network users of the ATM network can exclusively enjoy the entire bandwidth, even if the network Increasing the number of computers does not reduce the transfer rate

② Since ATM data is divided into cells of equal length, it can be processed more efficiently than traditional Packet switching makes it easier to achieve higher transmission rates

③Able to meet the transmission needs of data, voice, video and other multimedia data at the same time

④ Can be used in WAN and LAN at the same time. There is no need to select a route. Improved WAN transmission rates

①The transmission medium uses optical fiber, which has good anti-interference and confidentiality

②For the sake of seniority and fault tolerance, a double-ring structure is generally used, which has high reliability.

③ It has the characteristics of large scale, low error rate and high transmission rate, and can meet the requirements of broadband applications.

④The cost is too high and it is mainly used in the backbone network of large-scale networks.

①Expand wired LAN

②Connect the LAN between buildings

③Achieve roaming access

④Build a temporary network

Infrared radiation transmission technology

spread spectrum technology

①Wireless access point

②Wireless router

③Wireless network card

④Antenna

①Can provide exclusive bandwidth

②Short delay, easy to manage

③Can support multimedia communication

According to network coverage

Divided according to transmission medium and transmission speed

Divided according to application level

According to the structure of the switch

Divided according to the protocol layer in which the switch works

Divided according to whether network management functions are supported

Number of ports

port speed

Number of rack slots and expansion slots

Backplane bandwidth

Supported network types

MAC address table size

Maximum number of stacks

Can be managed via network

Maximum number of SONET ports

Supported protocols and standards

buffer size