There are many things worth learning about Ethernet switches. Here we mainly introduce how to avoid packet loss in the energy data control of Gigabit Ethernet switches. Flow control cannot improve the data throughput of the entire switch, but it avoids packet loss in the switch.  Gigabit Ethernet physical layer protocol IEEE defines several Gigabit Ethernet interfaces for different physical media, including 1000Base-CX, 1000Base-SX, 1000Base-LX, 1000Base-T.

Among them, 1000Base-CX is an interface used on 155Ω balanced coaxial cables. There is no real product in practice. 1000Base-T is an interface that can be used for category 5 or higher twisted pair cables. Its standard is IEEE802.3ab. This standard was just released in June 1999, and now commercial products have just been launched in the market.

1000Base—SX uses 850nm wavelength laser interface, which is only suitable for multimode fiber. 1000Base-LX uses 1300nm wavelength laser interface, suitable for single-mode and multi-mode fiber. 1000Base-SX is mainly used for campus network and enterprise network backbone.

1000Base-LX is mainly used in metropolitan area networks. Now another widely used metropolitan area network is the long-distance Gigabit Ethernet switch optical interface of 1000Base-LH. Generally, lasers with wavelengths of 1300nm or 1550nm are used, which can reach more than 50km. Even a transmission distance of 100km without relay.

It needs to be pointed out that, because the IEEE provides the Gigabit Ethernet transmission distance under the worst transmission conditions, in actual applications, the transmission distance of the products of various manufacturers far exceeds the standard provisions, such as Alcatel’s PowerRail 1000 The 1000Base-LX interface of the mega routing switch can transmit 22km without relay in the actual test.