第二层交换、第三层交换以及四层交换、多层交换,这些可以以交换技术一言以蔽之的技术正在网络界闹得沸沸扬扬。以大网交换技术的出现最早可追溯到本世纪的70年代,但真正的以太网交换器直到80年代末90年代初才出现。在短短的十几年间,交换式以太网已发展成了无可争议的局城网领袖。以太网交换技术的出现,对于改善网络性能,减轻网络负载和避免网络冲突有着巨大的作用。但随着时代的发展,网络应用的要求也越来越高,以太网交换技术也出现了一些局限性,从而也导致了一些“升级”技术,如虚拟局域网。但这些技术都可以看作是以太网交换技术的衍生物 The second exchange, the third exchange and exchange of the fourth floor, multi-layer exchange, these can be in exchange for the technology in a nutshell is uproar in the Internet industry. The emergence of big-net switching technology dates back to the 1970s as early as the turn of the century, but real Ethernet switches did not appear until the late 1980s and early 1990s. In just ten years, switched Ethernet has become the undisputed leader of the City Network. The emergence of Ethernet switching technology, to improve network performance, reduce network load and avoid network conflicts have a huge role. However, with the development of the times, the requirements of network applications are also getting higher and higher. Ethernet switching technologies also have some limitations, leading to some “upgrade” technologies such as virtual local area networks. But these technologies can be regarded as derivatives of Ethernet switching technology