10-Gigabit Ethernet技術淺釋

As the next generation of 1-Gigabit Ethernet, the 10-Gigabit Ethernet standard extends the IEEE 802.3ae standard protocols to a wire speed of 10 Gbps and expands the Ethernet application space to include WAN-compatible links. It performs for the best functions on optical fibre (high noise immunity) and operates in full-duplex mode. The 10-Gigabit Ethernet standard provides an increase significantly in bandwidth while maintaining the best compatibility with the already installed base of 802.3 standard interfaces, retains the existing principles of network operation and management.

Under the OSI model, the 10-Gigabit Ethernet retains the key Ethernet architecture, including the Media Access Control (MAC) protocol, the Ethernet frame format, and the minimum and maximum frame size. It continues the evolution of Ethernet in speed and distance, but retains the same Ethernet architecture used in other Ethernet specifications except one key ingredient. The 10-Gigabit Ethernet no longer needs the CSMA/CD protocol used in other Ethernet technologies. It matches the original Ethernet model in every other respect as well.

From the following figure shown, the Ethernet architecture further divides the physical layer into three sublayers: Physical Medium Dependent (PMD), Physical Medium Attachment (PMA), and Physical Coding Sublayer (PCS). PMDs provide the physical connection and signaling to the medium. The PCS consists of coding (e.g. 64B/66B) and a serializer or multiplexor. The IEEE 802.3ae standard defines two physical layer device (PHY) types: the LAN PHY and WAN PHY.

The 10-Gigabit Ethernet has the following features:

- Preserves the 802.3 Ethernet frame format.

- Preserves the minimum and maximum frame size of the current Ethernet standard.

- Supports full duplex operation only.

- Specifies an optional media independent interface (XGMII)

- Supports a speed of 10Gbps at the MAC interface.

- Defines two families of PHYs - LAN and WAN

The 10-Gigabit Ethernet, ten times the performance over 1-Gigabit Ethernet, allows a LAN to reach the operating distance up to 40 km. It will be the next step for enterprise and network service provider to implement sacled, intelligent, mulit-gigabit networks with backbone. It may be applied for the rapid increase and hungry requests of packetized voice, video and infomations data networks, especially on the network attached storage (NAS) and storage area networks (SAN). With 10-Gigabit backbones, it may enable greater implementation of bandwidth-intensive applications, such as streaming video, medical imaging, centralized terminal applications, high-end graphics and so on. Furthermore, it can greatly help make telecommuting, distance interactive and learning, digital videoconferencing, HDTV and enhanced Internet gaming etc.

With the pre-development of Gigabit Ethernet on facilities and technology, and addition of 10-Gigabit Ethernet to the Ethernet technology family, the 10-Gigabit Ethernet can be easily understood, widely deployed and backwards compatible into existing LAN networks.

(Referred from the website:

http://www.small-tree.com/pro10gbe_lr_sa_wp.pdf ,

http://www.intel.com/network/connectivity/resources/technologies/10_gigabit_ethernet.htm , http://www.xilinx-china.com/esp/wired/optical/net_tech/10_giga.htm )