2023年计算机等级四级网络工程师笔记交换机网桥中继器综合布线.doc

计算机等级四级网络工程师 笔记第五章互换机网桥中继器综合布线（Computer grade four, network engineer notes, fifth chapter switch, bridge, repeater, integrated wiring）计算机等级四级网络工程师 笔记第五章互换机网桥中继器综合布线(Computer grade four, network engineer notes, fifth chapter switch, bridge, repeater, integrated wiring) The LAN reference model corresponds to the physical layer and data link layer of the OSI model, which divides the DLC into LLC and MAC. Switched LAN is relative to shared LAN, and its core component is the switch. The switch adopts two kinds of forwarding technology (Shortcut switching mode and storage and forward switching mode) VLAN Based on virtual LAN switching technology, LAN of the node according to the logic is divided into several working groups, each group is a virtual network between multiple logical workstations to exchange data through Internet bridge or router, can use switch port, MAC the network layer address IP address, broadcast group definition of virtual LAN integrated wiring is a modular, highly flexible information transmission channel between buildings or buildings. Integrated wiring consists of components of different series and specifications, including transmission medium, related hardware, electrical protection equipment, etc. Compared with the traditional wiring, its advantages are: compatibility, openness, flexibility, reliability, advanced and economical composition of generic cabling system The work area subsystem: I. determine the number and types of information: information is divided into socket socket embedded installation socket (dark, twisted pair), surface mounted socket (Ming seat), multi media information socket (fiber and copper), usually choosing the area for the use of 0.75 of the actual area of the II. adapter The wiring (horizontal) subsystem: cable length should be within 90m wire type is determined according to the transmission rate (below 10M -4 or 5 UTP, 10M to 100M-5 or 6 class 100M, class -6 or above fiber) to determine the length of wire socket: information farthest from the connection between the the distance from the nearest Lmax, connection information socket distance Lmin, the average length of Lavr= (Lmax+Lmin) /2, the total length of =Lavr+ spare part + terminal error, spare part is equal to the general 0.1*Lavr Third, the trunk (vertical) subsystem (it is the nerve center of the integrated wiring system): the trunk subsystem, that is, the main feeder cable of the building and the 2 main combination methods of the cable laying of the trunk line: point to point combination and branch combination Equipment subsystem Management subsystem: including cross connecting equipment between trunk or satellite trunk line. There are three kinds of management subsystem: horizontal / trunk connection, connection of main line system and connection of building equipment The buildings subsystem: is the overhead wiring, wiring, wiring, tunnel buried underground pipeline wiring or any of the four laying modes of combination design level of integrated system basic type, enhancement type and integration standard United States standards, European standards, international standards, application standards, see P99 The network topology of the system is star type, ring type, bus type and network type, and the star type is the most used The main wiring components used in the integrated system are divided into transmission medium and connection device. The transmission medium is mainly twisted pair and optical fiber cable. Twisted pair is two copper core wires, in order to make the external electromagnetic radiation and reduce electromagnetic interference outside the morning so the twisted twisted pair is obtained. Fiber optic cables are divided into single-mode and multi-mode fiber. The connection hardware includes a connector for the main part (also called an adapter), a pair of connectors, and a cord. In accordance with international standards, the main components of integrated wiring connection used into buildings frame CD, building BD main frame, floor frame FD, TP transfer point, communication terminal TO TO between FD and the level of cable length should not exceed 90m construction of Integrated Engineering mainly refers to the distribution frame, wiring subsystem, transmission medium and communication leads (namely information socket) configuration Determine the number and type of information outlets: Adapter selection method the basic network Ethernet IEEE802.3 defines the MAC layer and physical layer protocol standard, although Ethernet MAC sublayer unified using the CSMA/CD method and the same frame structure, but physical layer technology can be different. method the traditional Ethernet named IEEE802.3 x Type-y Name x said the data transmission rate (Mbps), y is the largest segment of the length (100m), and the 2 is transmission using thin coaxial cable 5 is transmitted using thick coaxial cable, when using T y show that using double twisted pair Ethernet, Type transmission baseband (BASE) or Name band, said LAN name, if the formation of the Ethernet LAN LLC sub layer using the IEEE802.2 standard In the twisted pair network, is the center hub Ethernet connection device, in accordance with the hub, method twisted pair network can be divided into single and multi hub hub structure cascade structure, stackable hub structure, from the node to the maximum length of UTP hub for the 100m. When the number of nodes over a single port hub, usually need to use to connect port hub cascade to expand LAN coverage, the basic method stackable hub structure, multi hub cascade structure (which is composed of a base hub (that is, network management function of the independent component hub) and multiple expansion hub), regardless of the LAN which all nodes are located in the same domain in conflict Fast Ethernet Design Method the FE standard is IEEE802.3u, which uses the 802.2 standard in LLC. 100Base-T defines the medium specific interface (MII), which separates the MAC sublayer from the physical layer, so that changes in the transmission medium and signal encoding mode do not affect the MAC sublayer. 3: 100BASE-T standard transmission medium 100BASE-TX: use unshielded twisted pair UTP, maximum length 100m, full duplex 100BASE-T4: using UTP, 100m, 100BASE-FX: the half duplex optical fiber, 415m full duplex. FE supports full duplex (followed by the necessary point to point connection) and half duplex, E supports half duplex, and supports full duplex FE structure, must be star type. FE 10M and 100M rate negotiation with 10M and 100M rate card coexist rate supports automatic negotiation mechanism in a LAN, it can automatically determine the mode of remote work connected devices is a full duplex or half duplex and release of the information to the other nodes. The automatic negotiation function can only be used for twisted pair Ethernet, and specifies that the negotiation process needs to be completed within 500ms repeaters (with the coaxial cable used in physical layer) is used to increase the length of the coaxial cable Ethernet Repeater is designed, signal attenuation and distortion of the work process, after receiving, amplifying and shaping, which makes the signal waveform and the amplitude reached the agreement requirements, and then to the with its vector of another segment sent out, does not belong to the repeater network interconnection equipment hub (with twisted pair, physical layer) has the following characteristics: the Ethernet hub is the typical structure of the bus is connected to all nodes of a hub sharing each port of a collision domain and the hub are connected through the RJ-45 plug adapter. The standard UTP has 4 pairs of lines, the network connection type actually used 2 pairs, 1 pairs for sending 1 pairs for receiving bridge (LAN), data link layer: Bridge in DDL to complete data frame reception, forwarding and address filtering. When bridges are used to implement DDL connectivity, the protocol between the DDL and the physical layer of the internetwork is allowed to vary. The bridge features: 1, using two different Internet DDL protocol, different transmission media, different transmission rate of the network bridge to receive and transmit communication between Internet and address filtering way classification of bridges According to the frame forwarding strategy I: IEEE802.1d standard, transparent bridge by bridge instead of routing nodes, network interconnection generally used the same 2 MAC layer protocol is a plug and play device, transparent bridge MAC address table to record the address, port, station time. The transparent bridge uses the spanning tree algorithm, The protocol generated by the algorithm is a spanning tree protocol. The root bridge is selected from the network in a seat attribute topology roots; the shortest path overhead is a bridge and the shortest path to the root bridge for each non root bridge, is to choose a shortest path to the root port from its port as for each root port to choose a network port from the root bridge as recently designated ports will be responsible for this segment of data sent to the root bridge; spanning tree for each segment of a specified port, the other port in the blocking state, called blocking port II source routing bridge According to the number of bridge ports, it can be divided into two port bridge and multi port bridge According to the connection line of the bridge, it is divided into common LAN, bridge and wireless bridge. remote bridge the most important work of the bridge is to construct and maintain the MAC address table, and the parameters that evaluate the performance of the bridge are the frame filtering rate and the frame forwarding rate, and the bridge is connected in a shared memory space switch typical switched LANs are switched ethernet. Its core component is Ethernet switch, which implements the concurrent connection of multiple ports in hardware ,