10G Ethernet Explained
Ethernet technology has always been a computer network technology. The early LAN network technologies were proprietary to different manufacturers and were incompatible with each other. There was a phenomenon of a hundred schools of thought contending. In the late 1970s, dozens of local area network technologies had emerged, and Ethernet was just one of them. However, Ethernet gained popularity due to its low cost, high reliability, and relatively simple installation and maintenance, eventually taking the top spot for LANs.
With the advancement of the integration of computer networks and telecommunication networks and the development of high-speed urban networks, it is necessary to continuously increase the capacity of broadband networks and seek cost-effective solutions. A new solution stands out – 10G Ethernet technology. It offers speed advantages combined with flexibility, scalability, and technical simplicity. The introduction of 10G Ethernet technology is undoubtedly moving towards a goal – to use Ethernet technology from access to the backbone network, so that a broadband network that is different from traditional telecommunication networks can be constructed.
Ethernet technology is closely related to cabling technology. The earliest horizontal cables in the integrated wiring system used Category 3 cables, and the backbones used Category 5 cables or 100M optical fibers, and the system realized the application of 10M Ethernet; The system realizes the application of 100M fast Ethernet, and this mode gradually develops into the mainstream. From this, it is not difficult to see that when the ratio of the horizontal to the trunk rate is 1:10, there is basically no bottleneck at the trunk. With our higher and higher data transmission rate requirements, from 10M, 100M to today’s 1000M to the desktop, the cabling system has also developed from Category 3, Category 5, and Category 5 to Category 6. In order to maintain the smooth transmission of the network, How can the optical fiber system of the data transmission backbone not become the bottleneck of transmission? Should the trunk use 10 Gigabit? The answer is yes. When horizontally using 1000M Category 6 cable to the desktop, the backbone should use 10G fiber.
Since the theory proved that the maximum bandwidth of optical fiber can exceed 10T (1T=1024G), the application of optical fiber has always been the focus of attention, and it has been recognized as the ultimate information transmission medium in the future, and multimode fiber has always been a local area network such as high-rise buildings and campus networks. The main transmission medium is the backbone. With the formulation of the 10 Gigabit Ethernet standard, the application of 10 Gigabit Ethernet has become the general trend. Whether it is a short-term deployment or long-term planning, the preparation work must be arranged in advance. So, we believe 10 Gigabit Ethernet is here.
10G Ethernet Related Standards
IEEE802.3ae Standard
Among the many technologies for creating optical Ethernet, 10G Ethernet technology is currently the link layer technology that is highly concerned by the industry. IEEE has officially released the 802.3ae standard in June 2002, and the new standard still adopts IEEE802.3 Compared with the previous Ethernet standards, the Ethernet Media Access Control (MAC) protocol, frame format, and frame length mainly have the following differences:
(1) The new 64B/66B encoding method was introduced;
(2) Newly defined physical layer media types (two types of LAN/WAN, eight media types);
(3) Only define the fiber media type;
(4) Only full-duplex MAC layer operations are supported;
(5) The WIS interface sublayer is introduced into the WAN type, which provides the mapping and rate matching mechanism from MAC frames to OC-192 frames, and the channel overhead, line overhead, and segment overhead bytes are greatly simplified;
(6) The XAUI interface option is added under the XGMII interface, using 4 channels of 8 pairs of low-voltage differential serial signal lines for transmission, the transmission signal is coded by 8B/10B, and the signal has its own clock; the wiring distance from the MAC layer chip to the PHY chip is extended. up to 50cm, especially suitable for distributed rack systems;
(7) Support no relay link distance over 40km (SMF/ 1550nm), suitable for metropolitan area network applications.
IEEE802.3 10GBase-T Standard
In November 2002, the IEEE802.3 10GBase-T research group was formally established, which opened the prelude to the development of 10G copper cabling standards. The draft standard formulated is 10GBase-T, which refers to the implementation of 10G Ethernet on twisted-pair copper wires and is based on a widely installed copper cable cabling system. There are two main viewpoints, one is to sacrifice distance for speed, and the other is to sacrifice speed in exchange for distance. At present, the first view has dominated. The goal is to support 10G speed up to 55 to 100m on the Category 6e cabling system, and on the more advanced Category 7 cabling system. , support 10G rate up to 100m. The first draft of the standard is expected in June 2004, while the final standard (802.3an) will be released in June 2006.
IEEE 802.3ak Standard
The IEEE ratified a copper 10G Ethernet standard, IEEE802.3ak, in early 2004, which provides an economical route to short-haul, high-speed data center links.
IEEE 802.3ak is the IEEE standard for 10 Gigabit Ethernet over Coax. The 802.3ak passed this time is also called 10GBaseCX4 because it is specified to be transmitted over CX4 (ie, 4 pairs of twinax copper wires). This is the first copper Ethernet standard not to use Category 5 and Category 6 cable technology. According to the IEEE, the new standard provides an economical way to interconnect Ethernet switches and server clusters at 10Gbps speeds within a computer room within a distance of 15m.
According to relevant manufacturers, 10G copper ports are easier for enterprises to bear than the current fiber 10G ports. At the same time, it has also been predicted that the installation cost of copper 10GBase-CX4 interconnection will be one tenth of that of fiber optic 10GBase solutions.
10G Ethernet was originally developed as a long-haul operator technology, specifically to replace the SONET OC192 metropolitan area network with Ethernet. Interest in short-reach 10G for switch-to-switch interconnections, however, is starting to increase as businesses become interested in 10G, and the telecom recession forces operators to cut back on spending.
The IEEE has determined that Category 6/Class E systems need to expand their performance parameters to support 10Gbps applications. The extended performance parameters require a system capable of providing 625MHz of usable bandwidth. Siemon’s 10Gip™ solution is the first in the industry to offer guaranteed 625MHz performance and guaranteed 10Gbps applications over copper and fiber. The scheme consists of Category 6 unshielded, shielded, Category 7 fully shielded twisted pair systems, multimode and single mode fiber options.
It is estimated that at least 18Gbps of capacity will be required to transmit future 10GBase-T systems. Theoretical capacity is partly based on assumptions about existing mature technologies, such as 1000Base-T applications. The main challenge for UTP systems is to suppress noise from adjacent wire crosstalk. According to the research of the IEEE802.3an 10GBase-T research group, this technical difficulty limits the total channel length of the standard-based Category 6/Class E UTP system to between 55 and 100m.
Recent research by the 10GBase-T research group has proven that it is feasible to implement 10GBase-T with a capacity of less than 18Gbps. Implementing this technology by incorporating more complex channel codes (like low-density parity-corrected LDPC) and using higher performance UTP routing elements will enable 10Gbps applications to operate on channels up to 100m long.
