Fiber-optic Ethernet technology is now the integration and development of two major mainstream communications technologies, namely, Ethernet and optical networks. It focuses on the advantages of Ethernet and optical networks, such as Ethernet applications in general, low prices, networking flexibility, simple management, optical network reliability, capacity. The high speed and high capacity of optical Ethernet eliminates the bandwidth bottlenecks that exist between LANs and WANs and will become a single network architecture for future converged voice, data and video. Fiber-optic Ethernet products can use the Ethernet equipment using Ethernet packet format to achieve WAN communication services. At present, fiber Ethernet can achieve 10Mbps, 100Mbps and 1Gbps standard Ethernet speed. The following are the same as the "
Fiber-optic Ethernet devices are based on Layer 2 LAN switches, Layer 3 LAN switches, SONET devices, and DWDM. Some companies have introduced fiber-optic Ethernet switches, which have multiple features that ensure quality of service (such as packet classification and congestion management). This product may require the following key technologies and performance: high reliability, high port density, quality of service and other functions.
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Fiber-optic Ethernet business is more cost-effective than other broadband access, but so far its use is limited to office buildings or buildings where fiber has been laid. The strategic value of using this new approach to Ethernet is not limited to cheap access. It can be used either as an access network or as a local backbone network in a service provider network. It can only be used in the second layer, can also be used as an effective way to achieve the third layer of business. It can support IP, IPX and other traditional protocols. In addition, because it is inherently LAN, it can be used to help service providers manage the interconnection between enterprise LANs and enterprise LANs and other networks. The following are the same as the "
Optical fiber Ethernet access program
In the figure, the network core equipment is placed in the cell room or the building room of the optical switch, the fiber optic switch through the optical fiber to 1000M / 100M rate and Internet edge router or pool switch connected to achieve the regional network access to the Internet. The fiber switch is connected to the optical network unit or the built-in fiber Ethernet card placed at the user's home through optical fiber and point-to-point mode at a duplex 100M rate, enabling the user to access the Internet through fiber. The link between the optical switch and the optical network unit is to select the single-fiber bidirectional mode.
Switch cascade issues:
The switch cascade is between the switch and the switch through the exchange port to expand, so that on the one hand to solve the problem of a single switch port number, on the other hand also solve the remote room from the client and network equipment connection. Because the single-segment twisted pair Ethernet cable can reach 100 meters, each cascade of a switch can be extended 100 meters distance. But this is not to say that any cascade, because the line is too long, on the one hand the signal attenuation on the line are more, on the other hand, after all, subordinate switches or share a higher level of the switch port bandwidth, the more the final customer (Even though you may use the Fast switch), so that the impact of the network connection performance is very large, so from a real point of view, it is recommended to deploy up to three switches, that is, the core switch - two switches - Level 3 switches.
Where the three is not to say that only allow up to three switches, but from the level of speaking only three levels. Connected to the same switch on the same port switches are the same level, so each level can allow several, or even dozens of switches cascade. The port used for cascading can be a dedicated UpLink port or a common switch port. Some switches have dedicated cascading ports, but some do not. If there is a special cascade port, it is best to use, because its bandwidth is usually wider than the ordinary switching port, can further ensure that the lower switch bandwidth. If not only through the ordinary exchange port cascade.
Note that they are not only used between the different ports, the cable used is not the same: cascade port cascade, the need to use ordinary straight line; and the use of ordinary port cascade cable for the cross cable, like two hosts The same. As for the switch stack, not all switches can be, but to have a stack module. The stack of the switch is not carried out through the switch port, but through a dedicated backplane stack module, using a special stack cable for the connection. And note that because the switch stack is usually placed in the same location, the connection cable is also shorter, so the switch stack is mainly used to expand the exchange port, rather than for the expansion of the distance.
At the same time, the switch stack can also increase the bandwidth of the actual use of the switch port bandwidth, because it is the stack together with the backplane bandwidth of the switch together, so that the switch stack of the total backplane is a few stack switch backplane bandwidth Sum. After the backplane bandwidth is raised, this advantage is not obvious (if it is not possible to communicate with each port every time) if each port of the switch is used, but if there is a switch port Free, the effect will be more obvious, because it can take full advantage of all the bandwidth of the switch.
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