Research and application of Gigabit Ethernet netwo

Research and application of Gigabit Ethernet system in intelligent building

at present, intelligent building (IB) has become the mainstream of high-rise buildings. With the large-scale and multi-function of the building, all kinds of equipment in the building are increasing, and the building management is beyond the reach of human beings. The intelligent building adopts the "intelligent building management system", which adopts computer technology, control technology, communication technology and graphic display technology, that is, the so-called 4C technology is comprehensively applied to the building, and a computer integrated network is established in the building to make the building intelligent

system integration and function integration of intelligent building, that is, the integration of building automation system, office automation system and communication automation system and their corresponding subsystems on the public high-speed communication network. Therefore, it is necessary to establish a comprehensive and integrated computer network system in the building. Realizing network integration is the first step to realize system integration and function integration. In the construction of modern intelligent building, how to better provide safe, comfortable and fast high-quality services, how to establish an advanced and scientific comprehensive management mechanism, how to save energy consumption and reduce labor costs to meet the various needs of intelligent building users, it is extremely important to build a good computer network system of intelligent building. Gigabit Ethernet technology provides a high-quality solution to meet the above requirements of intelligent buildings

2. Computer network system

generally speaking, network integration is essentially the specific implementation of communication and network system in intelligent buildings, the combination of communication equipment and network equipment, and the combination of communication lines and network lines. Computer network is one of the important infrastructure of intelligent building. Broadly speaking, the computer network construction of the intelligent building is composed of four parts:

(1) the host or server of the backbone

Load master control center is connected with the local areas of the intelligent building and other office equipment. At present, the backbone transmission rate is generally required to reach 100mbit/s or above 1000mbit/s, requiring high reliability, certain coverage, scalability, and support a variety of network protocols. With the maturity of Gigabit Ethernet technology and various excellent performances, Gigabit Ethernet has become the first choice of many users

(2) floor local area

usually adopts bus Ethernet or token ring. At present, the switching technology based on 10mbit/s or 100mbit/s and its wide use make it possible for each workstation to enjoy 10mbit/s or 100mbit/s broadband alone. Floor local area can be configured with one or several local areas in one floor, or one local area in several floors. Different local areas can be connected through hubs, switches and routers

(3) computer monitoring of construction equipment

the information on the upper layer is generally Ethernet, and the lower layer is control, mostly using RS485 bus. However, due to the good openness and interoperability of fieldbus, it is developing towards fieldbus. The commonly used field bus mainly includes LonWorks bus and can bus

(4) external interconnection

external interconnection is the import and export channel of the information of the intelligent building. The external interconnection equipment will comprehensively utilize the existing and future communication means to realize the communication and information exchange between the intelligent building and the outside world. These communication means include satellite communication, microwave channel and. In addition, there are ground public communications, such as X.25 packet switching, digital data, and integrated services digital and frame relay

3. Gigabit Ethernet 19. Melt mass activity rate: gb/t 3682 ⑵ 000 technical characteristics for the determination of thermoplastic melt mass activity rate and melt volume activity rate

the standardization process of Gigabit Ethernet began in July 1996. After several months of preliminary feasibility study, the IEEE802.3 working group established the 802.3z Gigabit Ethernet task force. The task force developed Gigabit Ethernet standards, which mainly include: allowing full duplex and half duplex communication at gbit/s rate; 802.3 Ethernet frame format is used; Csma/cd is used as the access media protocol, and each conflict domain is allowed to relay once; It is fully backward compatible with 10Base-T and 100base-t. In short, Gigabit Ethernet has the following advantages:

(1) easy upgrade

when upgrading the system, Gigabit Ethernet provides an excellent migration path and fully protects the investment in the existing network infrastructure. Gigabit Ethernet will retain IEEE802.3 and Ethernet frame formats as well as 802.3 managed object specifications, so that while upgrading to Gigabit, the basic structure of the network will not be damaged, and the existing cables, operating systems, protocols, desktop applications and networks will be retained. The performance management strategy will be formally implemented on March 25 this year

(2) bottom of cost

Gigabit Ethernet is an economical and reliable way to improve the backbone connection between switches and the connection between switches and servers compared with the original backbone solutions such as fast Ethernet, FDDI, ATM, etc. The simplicity of Ethernet technology and the popularity of applications make the price of Gigabit Ethernet switches far lower than that of ATM switches. In addition, network maintenance is relatively easy, and there is no need to retrain managers

(3) new applications and data types

Gigabit Ethernet provides high bandwidth, so it is also very simple to wear broadband; Broadband reservation can be provided; New protocols that can be applied to Ethernet, such as RSVP; New standards such as 802.3q/1p support virtualization, message priority assignment, group playback and other functions. The above technologies make Gigabit switched Ethernet fully support multimedia applications, language, video transmission and other new data types, and have more advantages

(4) flexible network design and interconnection

network design must consider switching and routing, and must be able to easily expand the network. Gigabit Ethernet switches can support three-layer switching functions and integrate switching and routing. Therefore, when designing Gigabit switched Ethernet, you only need to care about the cost, rather than pay too much attention to considering network interconnection and network topology

4. Application of Gigabit Ethernet technology in intelligent building

in the computer network design of intelligent building, we must follow certain goals and principles, and the network collection system has good information exchange ability, high reliability and security, easy maintenance, easy expansion, etc

4.1 design objectives and principles of network import version

(1) design objectives

the computer network of intelligent building is a platform for intelligent building to provide information sharing and exchange, and realize external information exchange. Need to design a large intelligent building