The State of the Art of Ethernet Development for Legacy Ethernet

Ethernet is the most common communications protocol standard used in today's existing local area networks (LANs). The standard defines the types of cables and signaling methods used in local area networks (LANs). Ethernet transmits packets of information between interconnected devices at a rate of 10 to 100 Mbps, or even 1000 Mbps or more. Twisted-pair cable 10 Base T Ethernet is the most widely used Ethernet technology due to its low cost, high reliability, and 10 Mbps rate. Wireless Ethernet can be up to 300Mbps or more, and many manufacturing suppliers provide products that can communicate using common software protocols with the best openness.

Development

I. Standard Ethernet

Beginning of Ethernet is only 10Mbps throughput, using the CSMA/CD (Carrier Listening Multiple Access with Collision Detection) access control method, this early 10Mbps Ethernet is called standard Ethernet. There are two main types of Ethernet transmission media Network transmission media refers to the carrier of information transmission in the network, the commonly used transmission media are divided into two categories: 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, that is, twisted pair and optical fiber. All Ethernet follow the IEEE 802.3 standard, the following list is the IEEE 802.3 Ethernet standards, in these standards, the first number indicates the transmission speed, the unit is "Mbps", the last number indicates the length of a single segment of the network cable (the base unit is 100m), the Base indicates the "baseband". The last number represents the length of a single cable (the base unit is 100m), Base means "baseband", and Broad means "bandwidth".

10Base-5 uses thick coaxial cable with a maximum segment length of 500m, the baseband transmission method;

10Base-2 uses thin coaxial cable with a maximum segment length of 185m, the baseband transmission method;

10Base -T uses twisted-pair cable with a maximum segment length of 100m;

1Base-5 uses twisted-pair cable with a maximum segment length of 500m and a transmission speed of 1Mbps;

10Broad-36 uses coaxial cable (RG -59/U CATV), the maximum network segment length of 3600m, is a broadband transmission mode;

10Base-F using fiber-optic transmission medium, the transmission rate of 10Mbps;

Two, Fast Ethernet

With the development of the network, traditional standard Ethernet technology has been difficult to meet the increasing network data traffic speed requirements. Prior to October 1993, for LAN applications requiring more than 10Mbps of data traffic, only the Fiber Distributed Data Interface (FDDI) was available, but it was a very expensive, 100Mpbs fiber-optic cable-based LAN.In October 1993, Grand Junction launched the world's first Fast Ethernet hub Fastch10/100 and the network interface card FastNIC100, Fast Ethernet technology is officially applied. Subsequently, Intel, SynOptics, 3COM, BayNetworks and other companies have launched their own Fast Ethernet devices. At the same time, the IEEE802 engineering group also conducted research on various standards for 100Mbps Ethernet, such as 100BASE-TX, 100BASE-T4, MII, repeater, full-duplex, etc. In March 1995, the IEEE announced the IEEE802.3u 100BASE-T Fast Ethernet standard (Fast Ethernet), and thus began the era of Fast Ethernet.

Fast Ethernet and the original work in the 100Mbps bandwidth FDDI compared to it has many advantages, mainly reflected in the Fast Ethernet technology can effectively protect the user in the implementation of cabling infrastructure investment, which supports 3, 4, 5 twisted-pair cable as well as fiber optic connections, can effectively use the existing facilities. The shortcomings of Fast Ethernet are also the shortcomings of Ethernet technology, that is, Fast Ethernet is still based on CSMA/CD technology, when the network load is heavy, it will cause a reduction in efficiency, of course, this can be compensated by using switching technology. The 100Mbps Fast Ethernet standard is subdivided into three subcategories: 100BASE-TX , 100BASE-FX , and 100BASE-T4 .

100BASE-TX: is a Fast Ethernet technology that uses Category 5 data-grade unshielded twisted pair or shielded twisted pair. It uses two pairs of twisted pairs, one pair for transmitting and one pair for receiving data. It uses 4B/5B encoding for transmission at a signal frequency of 125 MHz and complies with the EIA586 Category 5 cabling standard and the IBM SPT Category 1 cabling standard. It uses the same RJ-45 connector as 10BASE-T. Its maximum segment length is 100 meters. It supports full-duplex data transmission.

100BASE-FX: is a Fast Ethernet technology that uses fiber optic cables and is available in single-mode and multimode fiber (62.5 and 125um) The maximum distance for multimode fiber connections is 550 meters. The maximum distance for a single-mode fiber connection is 3,000 meters. It uses 4B/5B coding method in transmission with a signal frequency of 125 MHz. it uses MIC/FDDI connectors, ST connectors or SC connectors. It has a maximum segment length of 150m, 412m, 2000m or longer up to 10km, depending on the type of fiber used and the mode of operation, and it supports full-duplex data transmission. 100BASE-FX is particularly suitable for application in environments with electrical interference, for larger distance connections, or for high-security environments.

100BASE-T4: is a Fast Ethernet technology that can use Category 3, 4, or 5 unshielded twisted pair or shielded twisted pair. 100Base-T4 uses four twisted pairs, three of which are used to transmit data at 33 MHz, with each pair operating in half-duplex mode. The fourth pair is used for CSMA/CD conflict detection. It uses the 8B/6T coding method in transmission with a signaling frequency of 25 MHz and complies with the EIA586 structured cabling standard. It uses the same RJ-45 connector as 10BASE-T and has a maximum segment length of 100 meters.

Three, Gigabit Ethernet

Gigabit Ethernet technology, as the latest high-speed Ethernet technology, brings users to improve the core network of effective solutions, the biggest advantage of this solution is inherited from the traditional advantages of cheap Ethernet technology. Gigabit technology is still Ethernet technology, which uses the same frame format, frame structure, network protocols, full/half-duplex mode of operation, flow control mode, and cabling system as 10M Ethernet. Since this technology does not change the traditional Ethernet desktop applications, operating systems, it works well with 10M or 100M Ethernet. Upgrading to Gigabit Ethernet maximizes investment protection by eliminating the need to change network applications, network management components, and network operating systems. Gigabit Ethernet supports shorter distances in order to detect collisions of 64Bytes frames. The types of networks supported by Gigabit Ethernet are listed in the table below:

Transmission Media 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 standards for fiber and short-haul copper connectivity solutions. IEEE802.3ab establishes standards for longer-haul connectivity solutions over Category 5 twisted-pair cable.

1. IEEE802.3z

The IEEE802.3z working group is responsible for developing standards for full-duplex links over optical fiber (singlemode or multimode) and coaxial cable.IEEE802.3z defines 1000Base-X based on fiber optic and short-range copper cables using 8B/10B coding technology, with a channel transmission speed of 1.25Gbit/ s, after decoupling to achieve 1000Mbit/s transmission speed. IEEE802.3z has the following Gigabit Ethernet standards:

1000Base-SX only supports multimode fiber, which can use multimode fiber with a diameter of 62.5um or 50um, operating at a wavelength of 770-860nm, and a transmission distance of 220-550m.

1000Base-LX multimode fiber: it can use multimode fiber with a diameter of 62.5um or 50um. 62.5um or 50um multi-mode fiber, the operating wavelength range is 1270-1355nm, and the transmission distance is 550m.

Single Mode Fiber: It can support 9um or 10um diameter single mode fiber, the operating wavelength range is 1270-1355nm, and the transmission distance is about 5km.

1000Base-CX uses 150-ohm shielded twisted pair (STP), and the transmission distance is 25m.

2. IEEE802.3ab

The IEEE802.3ab working group is responsible for developing the Gigabit Ethernet standard for half-duplex links based on UTP, which produces the IEEE802.3ab standard and protocol. IEEE802.3ab defines the 1000Base-T standard based on Category 5 UTP, which aims to transmit 100m over Category 5 UTP at a rate of 1000Mbit/s. The significance of the IEEE802.3ab standard is twofold:

(1) Protecting the user's investment in a Category 5 UTP cabling system.

(2) 1000Base-T is a natural extension of 100Base-T, and is fully compatible with 10Base-T, 100Base-T. However, to reach 1000Mbit/s transmission rate on Category 5 UTP need to solve the problem of crosstalk and attenuation of Category 5 UTP, therefore, making the development task of the IEEE802.3ab working group to be a little more complex than the IEEE802.3z

Four, 10 Gigabit Ethernet

The 10 Gigabit Ethernet specification is included in the complementary standard of the IEEE 802.3 standard IEEE 802.3ae extends the IEEE 802.3 protocol and MAC specifications to support 10Gb/s transmission rates. In addition, 10 Gigabit Ethernet can also be scaled to lower transmission rates, such as 9.584640 Gb/s (OC-192), through the WAN interface sublayer (WIS: WAN interface sublayer), which allows 10 Gigabit Ethernet devices to be compatible with the Synchronous Optical Networking (SONET) STS-192c transport format.

10GBASE-SR and 10GBASE-SW primarily support shortwave (850 nm) multimode fiber (MMF) with fiber distances from 2m to 300 m.

10GBASE-SR primarily supports "dark fiber", which is fiber that has no light propagation and is not connected to any device.

10GBASE-SW is primarily used to connect SONET devices, which are used for remote data communications.

10GBASE-LR and 10GBASE-LW primarily support longwave (1310nm) single-mode fiber (SMF) with fiber distances from 2m to 10km (about 32808 feet).

10GBASE-LW is primarily used when connecting to SONET devices,

10GBASE-LR is used to support "dark fiber".

10GBASE-ER and 10GBASE-EW primarily support ultra-longwave (1550nm) single-mode fiber (SMF) over distances ranging from 2m to 40km (~131,233 feet).

10GBASE-EW is primarily used to connect SONET devices,

10GBASE-ER is used to support "dark fiber.

10GBASE-LX4 uses wavelength-division multiplexing (WDM) technology to send signals at four times the wavelength of light over a single pair of cables. The system operates at 1310nm in either multimode or singlemode dark fiber mode. The system is designed for multimode fiber mode from 2m to 300m or singlemode fiber mode from 2m to 10km.