Ethereum LW
Such a long way, we must turn to the bus stop
take bus No.69 or the section of bus No.69 in Hangzhou Auto City, get off at the bus stop of north bus station at the terminal station, transfer to bus No.188, get off at the bus stop of No.1 Hospital in Hangzhou, walk to Pinghai Road bus station, take bus No.504, and get off at Zhuantang Street bus station
the table below is for reference, and the time should be at least 2.5 hours! The form is from Hangzhou Auto City to north bus station, you can take bus, the method is above
Ethernet is a kind of computer local area network technology. It is the most common local area network technology at present, replacing other local area network standards
Ethernet realizes the idea of sending information to multiple nodes in the wireless system on the network. Each node must obtain cables or channels to transmit information, including physical layer wiring, electronic signals and media access layer protocol
Ethernet can maximize the network speed and efficiency through the current fast Ethernet, so as to rece conflicts and use hub for network connection and organization
extended data
Ethernet network interface type
SC optical fiber interface type. SC optical fiber interface has been applied in the Ethernet era. There are many kinds of interfaces, which are mainly used in LAN switching environment. It is provided on some high-performance Ethernet switches and routers
FDDI interface type. FDDI is the highest transmission rate in Ethernet LAN technology. It has the characteristics of timed token protocol, supports a variety of topologies, and the transmission medium is optical fiber
RJ-45 interface type. This interface is the most common network equipment interface, commonly known as "crystal head", belongs to the type of twisted pair Ethernet interface, and the transmission medium is twisted pair
Ethernet is a LAN networking specification developed by Xerox, digital
equipment and Intel. It was first published in the early 1980s and is called dix1.0. The revised version in 1982 is dix2.0
these three companies submitted this specification to IEEE 802 Committee, which was revised and approved by IEEE members, and became the formal standard of IEEE with the number of IEEE 802.3. Although there are many different regulations between Ethernet and IEEE802.3, the term Ethernet is generally considered to be compatible with
802.3. IEEE submitted 802.3 standard to Joint Technical Committee 1 (JTC1) of international organization for Standardization (ISO)
Ethernet overview
Ethernet is the most common communication protocol
standard used in the current LAN, which was established in the early 1970s. Ethernet is a common LAN standard with transmission rate of 10Mbps. In Ethernet, all computers are connected to a coaxial cable. The CSMA / CD method with collision detection is adopted. The competition mechanism and bus topology are adopted. Basically, Ethernet consists of shared transmission media, such as twisted pair cable or coaxial cable, and multiport hubs, bridges, or switches. In a star or bus configuration, a hub / switch / bridge connects computers, printers, and workstations to each other through cables< The general characteristics of Ethernet are summarized as follows:
shared media: all network devices use the same communication media in turn
broadcast domain: the frame to be transmitted is sent to all nodes, but only the addressed node receives the frame
CSMA / CD: carrier
sense
multiple
access / collision
detection is used in Ethernet to prevent
twp
or more nodes from sending at the same time
MAC
address: all
Ethernet
network interface cards (NICS) in MAC layer adopt 48 bit network address. This kind of address is unique in the world
Ethernet
basic network composition:
shared media and cable: 10baset (twisted pair), 10base-2 (thin coaxial cable), 10BASE-5 (thick coaxial cable)
repeater or hub: a hub or hub is a type of device used to receive a large number of Ethernet connections on network devices. The data obtained by the receiving parties through a certain connection is reused and sent to all the connecting devices in the transmitting parties to obtain the transmitting device
bridge: the bridge belongs to the second layer equipment, which is responsible for dividing the network into independent conflict domains and segments, so as to achieve the goal of maintaining broadcasting and sharing in the same domain / segment. The bridge includes a table covering all segments and forwarding frames to ensure normal communication within and around segments
switch: switch, the same as bridge, belongs to the second layer device, and is a multi port device. The function supported by the switch is similar to the bridge, but it has the advantage over the bridge that it can temporarily connect any two ports together. The switch includes a switching matrix through which ports can be quickly connected or disconnected. Unlike a hub, a switch only forwards frames from one port to other connected target nodes and does not contain broadcast ports< Ethernet
protocol
: IEEE
802.3 standard provides Ethernet frame structure. Currently, Ethernet supports four transmission rates supported by optical fiber and twisted pair media:
10
Mbps
-
10Base-T
Ethernet (802.3)
100
Mbps
-
fast
Ethernet (802.3u)
1000
Mbps
-
Gigabit
Ethernet (802.3z))
10
Gigabit
Ethernet
-
IEEE
802.3ae
In the beginning, Ethernet only had a throughput of 10Mbps, and the access control method of carrier sense multiple access / collision detection (CSMA / CD) with collision detection was used. This early 10Mbps Ethernet is called standard Ethernet. Ethernet can be connected by thick coaxial cable, thin coaxial cable, unshielded twisted pair, shielded twisted pair and optical fiber. In the IEEE 802.3 standard, different physical layer standards are formulated for different transmission media. In these standards, the first number represents the transmission speed, and the unit is "Mbps", the last number represents the length of a single network line (the reference unit is 100m), base means "baseband", and broad means "broadband"
· 10BASE-5 uses a diameter of 0.4 inch and an impedance of 50 Ω Thick coaxial cable, also known as thick cable Ethernet, the maximum length of network segment is 500m. Baseband transmission method, topology for the total line. The main hardware equipment of 10BASE-5 networking includes thick coaxial cable, Ethernet card with AUI socket, repeater, transceiver, transceiver cable, terminator, etc
· 10base-2 uses a diameter of 0.2 inch and an impedance of 50 Ω Thin coaxial cable, also known as thin cable Ethernet, the maximum length of network segment is 185m, baseband transmission method, and the topology is general line; The main hardware equipment of 10base-2 networking includes: thin coaxial cable, Ethernet card with BNC socket, repeater, T-connector, terminator, etc
· 10Base-T uses twisted pair cable, and the maximum length of network segment is 100m. The topological structure is star; The main hardware equipment of 10Base-T networking includes: Class 3 or class 5 unshielded twisted pair, Ethernet card with RJ-45 socket, hub, switch, RJ-45 plug, etc
· 1base-5 uses twisted pair cable, the maximum network length is 500m, and the transmission speed is 1Mbps
· 10broad-36 uses coaxial cable (rg-59 / u CATV). The maximum span of the network is 3600m and the maximum length of the network segment is 1800m. It is a broadband transmission mode
· 10base-f uses optical fiber transmission medium with transmission rate of 10Mbps. With the development of network, the traditional standard Ethernet technology has been difficult to meet the increasing demand of network data flow speed. Before October 1993, only fiber distributed data interface (FDDI) was available for LAN applications requiring more than 10 Mbps data flow, but it was a very expensive LAN based on 100 Mbps optical cable. In October 1993, Grand Junction company launched the world's first fast Ethernet hub fastch10 / 100 and network interface card fastnic100, and the fast Ethernet technology was officially applied. Then Intel, synoptics, 3Com, baynetworks and other companies have launched their own fast Ethernet devices. At the same time, IEEE802 Engineering Group also studied various standards of 100Mbps Ethernet, such as 100base-tx, 100base-t4, m Ⅱ, repeater, full plex and so on. In March 1995, IEEE announced the IEEE 802.3u 100Base-T Fast Ethernet standard, which started the era of Fast Ethernet
Fast Ethernet has many advantages compared with FDDI which used to work under 100Mbps bandwidth, mainly reflected in that fast Ethernet technology can effectively guarantee the investment of users in the implementation of cabling, it supports the connection of type 3, 4, 5 twisted pair and optical fiber, and can effectively use the existing facilities. In fact, the deficiency of Fast Ethernet is also the deficiency of Ethernet technology, that is, fast Ethernet is still based on CSMA / CD technology. When the network load is heavy, it will rece the efficiency. Of course, this can be made up by switching technology. 100Mbps Fast Ethernet standard is divided into three sub categories: 100base-tx, 100Base-FX and 100base-t4
· 100base-tx: it is a fast Ethernet technology using class 5 data level unshielded twisted pair or shielded twisted pair. It uses two pairs of twisted pairs, one for sending and one for receiving data. 4b / 5B coding mode is used in the transmission, and the signal frequency is 125MHz. According to eia586 class 5 Wiring Standard and IBM SPT class 1 wiring standard. Use the same RJ-45 connector as 10base-t. Its maximum network segment length is 100 meters. It supports full plex data transmission
· 100Base-FX: it is a fast Ethernet technology using optical fiber, which can use single-mode and multi-mode optical fiber (62.5 and 125um). The maximum distance of multimode optical fiber connection is 550 meters. The maximum distance of single-mode fiber connection is 3000 meters. 4b / 5B coding mode is used in the transmission, and the signal frequency is 125MHz. It uses mic / FDDI connector, St connector or SC connector. Its maximum network segment length is 150m, 412m, 2000m or longer to 10km, which is related to the type of optical fiber used and working mode. It supports full plex data transmission. 100base FX is especially suitable for the environment with electrical interference, large distance connection, or high security environment
· 100base-t4: it is a fast Ethernet technology that can use 3, 4 and 5 kinds of unshielded twisted pair or shielded twisted pair. The 100base-t4 uses four pairs of twisted pairs, three of which are used to transmit data at 33MHz, and each pair works in half plex mode. The fourth pair is used for CSMA / CD conflict detection. 8B / 6T coding mode is used in the transmission, and the signal frequency is 25MHz, which conforms to eia586 structured wiring standard. It uses the same RJ-45 connector as 10Base-T, and the maximum length of network segment is 100m. As the latest high-speed Ethernet technology, Gigabit Ethernet technology brings users an effective solution to improve the core network. The biggest advantage of this solution is that it inherits the advantages of traditional Ethernet technology with low price. Gigabit technology is still Ethernet technology, which adopts the same frame format, frame structure, network protocol, full / half plex mode, flow control mode and wiring system as 10M Ethernet. Because this technology does not change the desktop application and operating system of traditional Ethernet, it can work well with 10m or 100M Ethernet. Upgrading to Gigabit Ethernet does not need to change network applications, network management components and network operating system, which can protect investment to the greatest extent. In addition, IEEE standard will support multimode fiber with a maximum distance of 550 meters, single-mode fiber with a maximum distance of 70 kilometers and coaxial cable with a maximum distance of 100 meters. Gigabit Ethernet fills the gap of 802.3 Ethernet / Fast Ethernet standard
in order to detect the collision of 64bytes data frame, Gigabit Ethernet supports shorter distance. The network types supported by Gigabit Ethernet are as follows:
transmission medium distance
1000base CX copper STP 25m
1000base t copper Cat 5 UTP 100m
1000base SX multi mode fiber 500m
1000base LX single mode fiber 3000m
there are two standards for Gigabit Ethernet Technology: ieee802.3z and ieee802.3ab. Ieee802.3z establishes the standard of optical fiber and short-range copper wire connection scheme. Ieee802.3ab formulates the standard of long distance connection scheme on five kinds of twisted pair< (1) ieee802.3z
ieee802.3z working group is responsible for formulating full plex link standards for optical fiber (single-mode or multi-mode) and coaxial cable. Ieee802.3z defines 1000base-x based on optical fiber and short distance copper cable, adopts 8B / 10B coding technology, the channel transmission speed is 1.25gbit/s, and realizes 1000mbit / s transmission speed after decoupling. Ieee802.3z has the following Gigabit Ethernet standards:
· 1000base SX only supports multimode optical fiber, which can be 62.5um or 50um in diameter, with working wavelength of 770-860nm and transmission distance of 220-550m
· 1000base LX single-mode fiber: it can support single-mode fiber with diameter of 9um or 10um, working wavelength range of 1270-1355nm and transmission distance of 5km
· 1000base CX adopts 150 ohm shielded twisted pair (STP), and the transmission distance is 25m< (2) ieee802.3ab
the ieee802.3ab working group is responsible for formulating the Gigabit Ethernet standard based on UTP half plex link and generating ieee802.3ab standard and protocol. Ieee802.3ab defines a 1000BASE-T standard based on class 5 UTP, which aims to transmit 100m at 1000mbit / s over class 5 UTP. The significance of ieee802.3ab standard mainly has two points:
1) to protect users' investment in Category 5 UTP cabling system< (2) 1000BASE-T is a natural extension of 100Base-T and is fully compatible with 10Base-T and 100base-t. However, to achieve the transmission rate of 1000mbit / s on class 5 UTP needs to solve the crosstalk and attenuation problems of class 5 UTP. Therefore, the development task of ieee802.3ab working group is more complex than that of ieee802.3z. 10 Gigabit Ethernet specification is included in IEEE 802.3ae, which is a supplement to IEEE 802.3 standard. It extends IEEE 802.3 protocol and MAC specification to support 10Gb / s transmission rate. In addition, through the WAN interface sublayer (WIS), 10 Gigabit Ethernet can also be adjusted to a lower transmission rate, such as 9.584640 GB / S (OC-192), which allows 10 Gigabit Ethernet devices to be compatible with the synchronous optical network (SONET) sts-192c transmission format
· 10gbase-sr and 10gbase-sw mainly support short wave (850 nm) multimode fiber (MMF), with fiber distance from 2m to 300 m
10gbase-sr mainly supports "dark fiber", which refers to the fiber without light propagation and not connected with any equipment
10gbase-sw is mainly used to connect SONET devices, which is used for remote data communication
· 10gbase-lr and 10gbase-lw mainly support long wave (1310nm) single-mode fiber (SMF), with fiber distance from 2m to 10km (about 32808 feet)< When 10gbase-lw is mainly used to connect SONET devices,
10gbase-lr is used to support "dark fiber"
· 10gbase-er and 10gbase-ew mainly support ultra long wave (1550nm) single mode fiber (SMF), with fiber distance from 2m to 40km (about 131233 feet)
10gbase-ew is mainly used to connect SONET devices, while
10gbase-er is used to support "dark fiber"
· 10gbase-lx4 uses wavelength division multiplexing technology to transmit signals on a single pair of optical cables at four times the optical wavelength. The system operates in 1310nm multimode or single-mode dark fiber mode. The design goal of the system is for the multimode fiber mode from 2m to 300m or the single-mode fiber mode from 2m to 10km
△ Ethernet connection
Ethernet is the most common communication protocol standard used in LAN nowadays. This standard defines the cable types and signal processing methods used in local area networks (LANs). Ethernet transmits packets at the rate of 10 ~ 100Mbps between interconnected devices, even more than 1000Mbps. Twisted pair cable 10base t Ethernet has become the most widely used Ethernet technology because of its low cost, high reliability and 10Mbps rate. Wireless Ethernet can reach more than 300mbps, and many procts provided by manufacturers can use common software protocol for communication, with the best openness
development status development
first, standard Ethernet
at the beginning, Ethernet only had the throughput of 10Mbps, using CSMA / CD (Carrier Sense Multiple Access with collision detection) access control method, this early 10Mbps Ethernet is called standard Ethernet. Ethernet mainly has two kinds of transmission media, network transmission media refers to the carrier of information transmission in the network. The commonly used transmission media are divided into wired transmission media and wireless transmission media 1) Wired transmission medium refers to the physical connection between two communication devices, which can transmit signals from one side to the other. The main wired transmission medium is twisted pair and optical fiber. All Ethernet networks follow the IEEE 802.3 standard. The following are some Ethernet standards of IEEE 802.3. In these standards, the first number represents the transmission speed, and the unit is "Mbps", the last number represents the length of a single network cable (the base unit is 100m), base means "baseband", and broad means "bandwidth"
10BASE-5 uses thick coaxial cable, the maximum length of network segment is 500m, and baseband transmission method is adopted
10base-2 uses thin coaxial cable, the maximum length of network segment is 185m, and the baseband transmission method is adopted
10Base-T uses twisted pair cable, and the maximum network segment length is 100m
1base-5 uses twisted pair cable, the maximum network length is 500m, and the transmission speed is 1Mbps
10broad-36 uses coaxial cable (rg-59 / u CATV) with a maximum length of 3600m, which is a broadband transmission mode
10base-f uses optical fiber transmission medium, and the transmission rate is 10Mbps
Second, fast Ethernet
with the development of network, the traditional standard Ethernet technology has been difficult to meet the increasing demand of network data flow speed. Before October 1993, only fiber distributed data interface (FDDI) was available for LAN applications requiring more than 10Mbps data flow, but it was a very expensive LAN based on 100Mbps optical cable. In October 1993, Grand Junction company launched the world's first fast Ethernet hub fastch10 / 100 and network interface card fastnic100, and the fast Ethernet technology was officially applied. Then Intel, synoptics, 3Com, baynetworks and other companies have launched their own fast Ethernet devices. At the same time, IEEE802 Engineering Group also studied various standards of 100Mbps Ethernet, such as 100base-tx, 100base-t4, MII, repeater, full plex and so on. In March 1995, IEEE announced the IEEE 802.3u 100Base-T Fast Ethernet standard, which started the era of Fast Ethernet
Fast Ethernet has many advantages compared with FDDI which used to work under 100Mbps bandwidth, mainly reflected in that fast Ethernet technology can effectively guarantee the investment of users in the implementation of cabling, it supports the connection of type 3, 4, 5 twisted pair and optical fiber, and can effectively use the existing facilities. In fact, the deficiency of Fast Ethernet is also the deficiency of Ethernet technology, that is, fast Ethernet is still based on CSMA / CD technology. When the network load is heavy, it will rece the efficiency. Of course, this can be made up by switching technology. 100Mbps Fast Ethernet standard is divided into three sub categories: 100base-tx, 100Base-FX and 100base-t4
100base-tx: it is a fast Ethernet technology using class 5 data level unshielded twisted pair or shielded twisted pair. It uses two pairs of twisted pairs, one for sending and one for receiving data. 4b / 5B coding mode is used in the transmission, and the signal frequency is 125MHz. According to eia586 class 5 Wiring Standard and IBM SPT class 1 wiring standard. Use the same RJ-45 connector as 10base-t. Its maximum network segment length is 100 meters. It supports full plex data transmission
100Base-FX: it is a fast Ethernet technology using optical cable, which can use single-mode and multi-mode optical fiber (62.5um and 125um) to connect the maximum distance of 550m. The maximum distance of single-mode fiber connection is 3000 meters. 4b / 5B coding mode is used in the transmission, and the signal frequency is 125MHz. It uses mic / FDDI connector, St connector or SC connector. Its maximum network segment length is 150m, 412m, 2000m or longer to 10km, which is related to the type of optical fiber used and working mode. It supports full plex data transmission. 100base FX is especially suitable for the environment with electrical interference, large distance connection, or high security environment
100base-t4: it is a fast Ethernet technology that can use 3, 4 and 5 kinds of unshielded twisted pair or shielded twisted pair. The 100base-t4 uses four pairs of twisted pairs, three of which are used to transmit data at 33MHz, and each pair works in half plex mode. The fourth pair is used for CSMA / CD conflict detection. 8B / 6T coding mode is used in the transmission, and the signal frequency is 25MHz, which conforms to eia586 structured wiring standard. It uses the same RJ-45 connector as 10Base-T, and the maximum length of network segment is 100m< As the latest high-speed Ethernet technology, Gigabit Ethernet technology brings users an effective solution to improve the core network. The biggest advantage of this solution is that it inherits the advantages of traditional Ethernet technology, which is cheap. Gigabit technology is still Ethernet technology, which adopts the same frame format, frame structure, network protocol, full / half plex mode, flow control mode and wiring system as 10M Ethernet. Because this technology does not change the desktop application and operating system of traditional Ethernet, it can work well with 10m or 100M Ethernet. Upgrading to Gigabit Ethernet does not need to change network applications, network management components and network operating system, which can maximize investment protection. In order to detect the collision of 64bytes data frame, the distance supported by Gigabit Ethernet is shorter. The network types supported by Gigabit Ethernet are as follows:
transmission medium distance
1000base CX copper STP 25m
1000base t copper Cat 5 UTP 100m
1000base SX multi mode fiber 500m
1000base LX single mode fiber 3000m
there are two standards for Gigabit Ethernet Technology: ieee802.3z and ieee802.3ab. Ieee802.3z establishes the standard of optical fiber and short-range copper wire connection scheme. Ieee802.3ab formulates the standard of long distance connection scheme on five kinds of twisted pair< Ieee802.3z
the ieee802.3z working group is responsible for formulating full plex link standards for optical fiber (single-mode or multi-mode) and coaxial cable. Ieee802.3z defines 1000base-x based on optical fiber and short distance copper cable, adopts 8B / 10B coding technology, the channel transmission speed is 1.25gbit/s, and realizes 1000mbit / s transmission speed after decoupling. Ieee802.3z has the following Gigabit Ethernet standards:
1000base SX only supports multimode optical fiber, which can be 62.5um or 50um in diameter, with working wavelength of 770-860nm and transmission distance of 220-550m
1000base LX multimode fiber: the multimode fiber with diameter of 62.5um or 50um can be used, the working wavelength range is 1270-1355nm, and the transmission distance is 550m
single mode fiber: it can support single-mode fiber with diameter of 9um or 10um, working wavelength range of 1270-1355nm and transmission distance of 5km
1000base CX adopts 150 ohm shielded twisted pair (STP), and the transmission distance is 25m< Ieee802.3ab
the working group of ieee802.3ab is responsible for formulating the Gigabit Ethernet standard based on UTP half plex link and generating ieee802.3ab standard and protocol. Ieee802.3ab defines a 1000BASE-T standard based on class 5 UTP, which aims to transmit 100m at 1000mbit / s over class 5 UTP. The significance of ieee802.3ab standard mainly has two points:
(1) to protect users' investment in Category 5 UTP cabling system
(2) 1000BASE-T is a natural extension of 100Base-T and is fully compatible with 10Base-T and 100base-t. However, to achieve the transmission rate of 1000mbit / s on Class-5 UTP, the crosstalk and attenuation problems of Class-5 UTP need to be solved. Therefore, the development task of ieee802.3ab working group is more complicated than that of ieee802.3z
4. The specification of 10 Gigabit Ethernet is included in IEEE 802.3ae, a supplementary standard of IEEE 802.3 standard, It extends IEEE 802.3 protocol and MAC specification to support 10Gb / s transmission rate. In addition, through the WAN interface sublayer (WIS), 10 Gigabit Ethernet can also be adjusted to a lower transmission rate, such as 9.584640 GB / S (OC-192), which allows 10 Gigabit Ethernet devices to be compatible with the synchronous optical network (SONET) sts-192c transmission format
10gbase-sr and 10gbase-sw mainly support short wave (850 nm) multimode fiber (MMF), with fiber distance from 2m to 300 m
10gbase-sr mainly supports "dark fiber", which refers to the fiber without light propagation and not connected with any equipment
10gbase-sw is mainly used to connect SONET devices, which is used for remote data communication
10gbase-lr and 10gbase-lw mainly support long wave (1310nm) single-mode fiber (SMF), with fiber distance from 2m to 10km (about 32808ft)< When 10gbase-lw is mainly used to connect SONET devices,
10gbase-lr is used to support "dark fiber"
10gbase-er and 10gbase-ew mainly support ultra long wave (1550nm) single mode fiber (SMF), with fiber distance from 2m to 40km (about 131233 feet)
10gbase-ew is mainly used to connect SONET devices, while
10gbase-er is used to support "dark fiber"
10gbase-lx4 uses wavelength division multiplexing technology to transmit signals at four times the optical wavelength on a single pair of optical cables. The system operates in 1310nm multimode or single-mode dark fiber mode. The design goal of the system is for the multimode fiber mode from 2m to 300m or the single-mode fiber mode from 2m to 10km
Second, fast Ethernet
with the development of network, the traditional standard Ethernet technology has been difficult to meet the increasing demand of network data flow speed. Before October 1993, only fiber distributed data interface (FDDI) was available for LAN applications requiring more than 10Mbps data flow, but it was a very expensive LAN based on 100Mbps optical cable. In October 1993, Grand Junction company launched the world's first fast Ethernet hub fastch10 / 100 and network interface card fastnic100, and the fast Ethernet technology was officially applied. Then Intel, synoptics, 3Com, baynetworks and other companies have launched their own fast Ethernet devices. At the same time, IEEE802 Engineering Group also studied various standards of 100Mbps Ethernet, such as 100base-tx, 100base-t4, MII, repeater, full plex and so on. In March 1995, IEEE announced the IEEE 802.3u 100Base-T Fast Ethernet standard, which started the era of Fast Ethernet. Fast Ethernet has many advantages compared with FDDI, which used to work in 100Mbps bandwidth. The most important one is that fast Ethernet technology can effectively guarantee the investment of users in the implementation of cabling. It supports the connection of 3,4,5 types of twisted pair and optical fiber, and can effectively use the existing facilities. In fact, the deficiency of Fast Ethernet is also the deficiency of Ethernet technology, that is, fast Ethernet is still based on CSMA / CD technology. When the network load is heavy, it will rece the efficiency. Of course, this can be made up by switching technology. 100Mbps Fast Ethernet standard is divided into three sub categories: 100base-tx, 100Base-FX and 100base-t4· 100base-tx: it is a fast Ethernet technology using class 5 data level unshielded twisted pair or shielded twisted pair. It uses two pairs of twisted pairs, one for sending and one for receiving data. 4b / 5B coding mode is used in the transmission, and the signal frequency is 125MHz. According to eia586 class 5 Wiring Standard and IBM SPT class 1 wiring standard. Use the same RJ-45 connector as 10base-t. Its maximum network segment length is 100 meters. It supports full plex data transmission· 100Base-FX: it is a fast Ethernet technology using optical cable. It can use single-mode and multi-mode optical fiber (62.5um and 125um). The maximum distance of multi-mode optical fiber connection is 550m. The maximum distance of single-mode fiber connection is 3000 meters. 4b / 5B coding mode is used in the transmission, and the signal frequency is 125MHz. It uses mic / FDDI connector, St connector or SC connector. Its maximum network segment length is 150m, 412m, 2000m or longer to 10km, which is related to the type of optical fiber used and working mode. It supports full plex data transmission. 100base FX is especially suitable for the environment with electrical interference, large distance connection, or high security environment· 100base-t4: it is a fast Ethernet technology that can use 3, 4 and 5 kinds of unshielded twisted pair or shielded twisted pair. The 100base-t4 uses four pairs of twisted pairs, three of which are used to transmit data at 33MHz, and each pair works in half plex mode. The fourth pair is used for CSMA / CD conflict detection. 8B / 6T coding mode is used in the transmission, and the signal frequency is 25MHz, which conforms to eia586 structured wiring standard. It uses the same RJ-45 connector as 10Base-T, and the maximum length of network segment is 100m< As the latest high-speed Ethernet technology, Gigabit Ethernet technology brings users an effective solution to improve the core network. The biggest advantage of this solution is that it inherits the advantages of traditional Ethernet technology, which is cheap. Gigabit technology is still Ethernet technology, which adopts the same frame format, frame structure, network protocol, full / half plex mode, flow control mode and wiring system as 10M Ethernet. Because this technology does not change the desktop application and operating system of traditional Ethernet, it can work well with 10m or 100M Ethernet. Upgrading to Gigabit Ethernet does not need to change network applications, network management components and network operating system, which can maximize investment protection. In order to detect the collision of 64bytes data frame, the distance supported by Gigabit Ethernet is shorter. The network types supported by Gigabit Ethernet are shown in the following table: transmission medium distance 1000base-cx copper STP 25m 1000BASE-T copper Cat 5 UTP 100m 1000base SX multi mode fiber 500m 1000base LX single mode fiber 3000m. There are two standards for Gigabit Ethernet Technology: ieee802.3z and ieee802.3ab. Ieee802.3z establishes the standard of optical fiber and short-range copper wire connection scheme. Ieee802.3ab formulates the standard of long distance connection scheme on five kinds of twisted pair. 1. Ieee802.3z ieee802.3z working group is responsible for formulating full plex link standards for optical fiber (single-mode or multi-mode) and coaxial cable. Ieee802.3z defines 1000base-x based on optical fiber and short distance copper cable, adopts 8B / 10B coding technology, the channel transmission speed is 1.25gbit/s, and realizes 1000mbit / s transmission speed after decoupling. Ieee802.3z has the following Gigabit Ethernet standards: · 1000base SX only supports multimode optical fiber, which can be 62.5um or 50um in diameter, with working wavelength of 770-860nm and transmission distance of 220-550m· 1000base LX multimode fiber: the multimode fiber with diameter of 62.5um or 50um can be used, the working wavelength range is 1270-1355nm, and the transmission distance is 550m. Single mode fiber: it can support single-mode fiber with diameter of 9um or 10um, working wavelength range of 1270-1355nm and transmission distance of 5km· 1000base CX adopts 150 ohm shielded twisted pair (STP) with transmission distance of 25m. 2. Ieee802.3ab the working group of ieee802.3ab is responsible for formulating the Gigabit Ethernet standard based on UTP half plex link and generating ieee802.3ab standard and protocol. Ieee802.3ab defines a 1000BASE-T standard based on class 5 UTP, which aims to transmit 100m at 1000mbit / s over class 5 UTP. The significance of ieee802.3ab standard has two main points: (1) to protect users' investment in five types of UTP cabling system 2) 1000BASE-T is a natural extension of 100Base-T and is fully compatible with 10Base-T and 100base-t. However, to achieve the transmission rate of 1000mbit / s on Class-5 UTP, the crosstalk and attenuation problems of Class-5 UTP need to be solved. Therefore, the development task of ieee802.3ab working group is more complicated than that of ieee802.3z
4. The specification of 10 Gigabit Ethernet is included in IEEE 802.3ae, a supplementary standard of IEEE 802.3 standard, It extends IEEE 802.3 protocol and MAC specification to support 10Gb / s transmission rate. In addition, through the WAN interface sublayer (WIS), 10 Gigabit Ethernet can also be adjusted to a lower transmission rate, such as 9.584640 GB / S (OC-192), which allows 10 Gigabit Ethernet devices to be compatible with the synchronous optical network (SONET) sts-192c transmission format· 10gbase-sr and 10gbase-sw mainly support short wave (850 nm) multimode fiber (MMF), with fiber distance from 2m to 300 m. 10gbase-sr mainly supports "dark fiber", which refers to the fiber without light propagation and not connected with any equipment. 10gbase-sw is mainly used to connect SONET devices, which is used for remote data communication· 10gbase-lr and 10gbase-lw mainly support long wave (1310nm) single-mode fiber (SMF), with fiber distance from 2m to 10km (about 32808ft). When 10gbase-lw is mainly used to connect SONET devices, 10gbase-lr is used to support "dark fiber"· 10gbase-er and 10gbase-ew mainly support ultra long wave (1550nm) single mode fiber (SMF), with fiber distance from 2m to 40km (about 131233 feet). 10gbase-ew is mainly used to connect SONET devices, while 10gbase-er is used to support "dark fiber"· 10gbase-lx4 uses wavelength division multiplexing technology to transmit signals on a single pair of optical cables at four times the optical wavelength. The system operates in 1310nm multimode or single-mode dark fiber mode. The design goal of the system is for the multimode fiber mode from 2m to 300m or the single-mode fiber mode from 2m to 10km.
token ring network was developed by IBM in the 1970s, but it is rare now. In the old token ring network, the data transmission speed is 4Mbps or 16mbps, and the new fast token ring network can reach 100Mbps. The transmission method of token ring network adopts star topology physically, but it is still ring topology logically. Its communication transmission medium can be unshielded twisted pair, shielded twisted pair and optical fiber. The nodes are connected by multi station access unit (MAU). Mau is a specialized hub, which is used to transmit around the loop of workstation computer. Since the packet looks like it's being transmitted in the ring, there is no terminator in the workstation and Mau
in this kind of network, there is a special frame called "token", which continuously transmits on the loop to determine when a node can send packets. The token is 24 bits long and has three 8-bit domains, which are start descriptor (SD), access control (AC) and end descriptor (ED). A prefix is a distinctive signal pattern, which is presented as a non data signal to prevent it from being interpreted as something else. This unique 8-bit combination can only be recognized as a frame first identifier (SOF)
the media access control mechanism of token ring network adopts the circulation method of distributed control mode. In token ring network, there is a token which is passed in turn along the ring bus between the computers of the network access nodes. The token is actually a special format frame, which does not contain information. It only controls the use of the channel to ensure that only one node can monopolize the channel at the same time. When all the nodes on the ring are idle, the token moves around the ring. The node computer can only send data frames after obtaining the token, so there will be no collision. Because the token is delivered in order on the ring, the access right is fair to all computers
there are two states of Token: idle and busy“ "Idle" means that the token is not occupied, that is, no computer is transmitting information in the network“ "Busy" indicates that the token has been occupied, that is, information is being transmitted in the network. The computer that wants to transfer data must first detect the "idle" token, set it to the "busy" state, and then transfer data after the token. When the data is received by the destination computer, the data is removed from the network and the token is reset to "idle". The disadvantage of token ring network is that it needs to maintain the token. Once the token is lost, it can not work. It needs to select a special node to monitor and manage the token. Due to the rapid development of Ethernet technology and the inherent shortcomings of token network, token network is rare in the whole computer LAN. Most of the manufacturers who originally provided token network equipment have also withdrawn from the market. Therefore, token network can be said to be "a thing of the past" in the current LAN Market
www.taiwang.com makes it easier for readers to understand and have something to refer to when reading. History
the initial development of Ethernet technology came from one of many pioneering technology projects of Xerox Palo Alto Research Center. Ethernet is generally believed to have been invented in 1973, when Robert Metcalfe wrote a memo to his Parc boss about the potential of Ethernet. But Metcalfe himself believes that Ethernet came into being only a few years later. In 1976, Metcalf and his assistant David Boggs published an article entitled "Ethernet: distributed packet switching technology for local computer networks"
in 1979, Metcalf left Xerox to develop personal computers and local area networks and founded 3Com. 3com lobbied digito, Intel, and Xerox to work with them to standardize Ethernet. This general Ethernet standard was issued on September 30, 1980. At that time, there were two popular non-public network standards, token ring network and ARCNET. Under the impact of the tide of Ethernet, they were quickly shrunk and replaced. In this process, 3Com has become an international company
Metcalf once joked that Jerry saltzer contributed to 3Com's success. Saltzer pointed out in an influential paper that token ring network is superior to Ethernet in theory. Influenced by this conclusion, many computer manufacturers are hesitant or decide not to use Ethernet interface as the standard configuration of the machine, so 3Com will have the opportunity to make a big profit from selling Ethernet network card. This situation also leads to another saying that "Ethernet is not suitable for theoretical research, but only for practical application". Maybe it's just a joke, but it illustrates such a technical viewpoint: generally, the actual data flow characteristics in the network are different from the estimation before the popularity of LAN, and it is the simple structure of Ethernet that makes LAN popular. Metcalfe and saltzer worked on the same floor of the MAC project at MIT when he was working on his Harvard thesis, laying the theoretical foundation for Ethernet technology
Ethernet. It refers to the baseband LAN specification created by Xerox and jointly developed by Xerox, Intel and Dec. Ethernet uses CSMA / CD (carrier sense multiple access and conflict detection) technology, and runs on various types of cables at the rate of 10m / s. Ethernet is similar to IEEE802.3 series standard
it is not a specific network, but a technical specification
Ethernet is the most common communication protocol standard used in LAN nowadays. This standard defines the cable types and signal processing methods used in local area networks (LANs). Ethernet transmits packets at the rate of 10 ~ 100Mbps between interconnected devices. Twisted pair cable 10base t Ethernet has become the most widely used Ethernet technology because of its low cost, high reliability and 10Mbps rate. DSSS wireless Ethernet can reach 11Mbps, and many procts provided by manufacturers can use common software protocol for communication, with the best openness. 1、 Standard Ethernet
in the beginning, the throughput of Ethernet was only 10Mbps, and the access control method of CSMA / CD (Carrier Sense Multiple Access with collision detection) was used. This early 10Mbps Ethernet was called standard Ethernet. Ethernet mainly has two kinds of transmission media, that is twisted pair and optical fiber. All Ethernet networks follow the IEEE 802.3 standard. The following are some Ethernet standards of IEEE 802.3. In these standards, the first number represents the transmission speed, and the unit is "Mbps", the last number represents the length of a single network cable (the base unit is 100m), base means "baseband", and broad means "bandwidth"
· 10BASE-5 uses thick coaxial cable, the maximum network segment length is 500m, and the baseband transmission method is adopted
· 10base-2 uses thin coaxial cable, the maximum length of network segment is 185m, and the baseband transmission method is adopted
· 10Base-T uses twisted pair cable, and the maximum network segment length is 100m
· 1base-5 uses twisted pair cable, the maximum network length is 500m, and the transmission speed is 1Mbps
· 10broad-36 uses coaxial cable (rg-59 / u CATV) with a maximum length of 3600m, which is a broadband transmission mode
· 10base-f uses optical fiber transmission medium with transmission rate of 10Mbps
Second, fast Ethernet
with the development of network, the traditional standard Ethernet technology has been difficult to meet the increasing demand of network data flow speed. Before October 1993, only fiber distributed data interface (FDDI) was available for LAN applications requiring more than 10Mbps data flow, but it was a very expensive LAN based on 100Mbps optical cable. In October 1993, Grand Junction company launched the world's first fast Ethernet hub fastch10 / 100 and network interface card fastnic100, and the fast Ethernet technology was officially applied. Then Intel, synoptics, 3Com, baynetworks and other companies have launched their own fast Ethernet devices. At the same time, IEEE802 Engineering Group also studied various standards of 100Mbps Ethernet, such as 100base-tx, 100base-t4, MII, repeater, full plex and so on. In March 1995, IEEE announced the IEEE 802.3u 100Base-T Fast Ethernet standard, which started the era of Fast Ethernet
Fast Ethernet has many advantages compared with FDDI which used to work under 100Mbps bandwidth, mainly reflected in that fast Ethernet technology can effectively guarantee the investment of users in the implementation of cabling, it supports the connection of type 3, 4, 5 twisted pair and optical fiber, and can effectively use the existing facilities. In fact, the deficiency of Fast Ethernet is also the deficiency of Ethernet technology, that is, fast Ethernet is still based on CSMA / CD technology. When the network load is heavy, it will rece the efficiency. Of course, this can be made up by switching technology. 100Mbps Fast Ethernet standard is divided into three sub categories: 100base-tx, 100Base-FX and 100base-t4
· 100base-tx: it is a fast Ethernet technology using class 5 data level unshielded twisted pair or shielded twisted pair. It uses two pairs of twisted pairs, one for sending and one for receiving data. 4b / 5B coding mode is used in the transmission, and the signal frequency is 125MHz. According to eia586 class 5 Wiring Standard and IBM SPT class 1 wiring standard. Use the same RJ-45 connector as 10base-t. Its maximum network segment length is 100 meters. It supports full plex data transmission
· 100Base-FX: it is a fast Ethernet technology using optical cable. It can use single-mode and multi-mode optical fiber (62.5um and 125um) to connect the maximum distance of 550m. The maximum distance of single-mode fiber connection is 3000 meters. 4b / 5B coding mode is used in the transmission, and the signal frequency is 125MHz. It uses mic / FDDI connector, St connector or SC connector. Its maximum network segment length is 150m, 412m, 2000m or longer to 10km, which is related to the type of optical fiber used and working mode. It supports full plex data transmission. 100base FX is especially suitable for the environment with electrical interference, large distance connection, or high security environment
· 100base-t4: it is a fast Ethernet technology that can use 3, 4 and 5 kinds of unshielded twisted pair or shielded twisted pair. The 100base-t4 uses four pairs of twisted pairs, three of which are used to transmit data at 33MHz, and each pair works in half plex mode. The fourth pair is used for CSMA / CD conflict detection. 8B / 6T coding mode is used in the transmission, and the signal frequency is 25MHz, which conforms to eia586 structured wiring standard. It uses the same RJ-45 connector as 10Base-T, and the maximum length of network segment is 100m< As the latest high-speed Ethernet technology, Gigabit Ethernet technology brings users an effective solution to improve the core network. The biggest advantage of this solution is that it inherits the advantages of traditional Ethernet technology, which is cheap. Gigabit technology is still Ethernet technology, which adopts the same frame format, frame structure, network protocol, full / half plex mode, flow control mode and wiring as 10M Ethernet