tailieunhanh - wiley nortel guide to vpn routing for security and voip phần 2

các tập tin phương tiện truyền thông bằng cách sử dụng một giao thức khác với HTTP, để nó có thể được xem trong thời gian thực. Các máy chủ cung cấp một dòng dữ liệu đến một | 42 Chapter 2 Hardware Interface Options Many of the Nortel VPN Routers discussed so far have optional equipment that can be supported. This section discusses some of these optional modules and what each one can offer. Peripheral Component Interconnect Expansion Slots The Peripheral Component Interconnect PCI is a computer-based standard that specifies the subsystem that provides for the transfer of data between multiple computer components. PCI devices can be the circuits that are installed on a computer motherboard as well as expansion modules that fit into expansion slots on a computer motherboard. By providing these expansion slots and developing the separate expansion modules users gain more flexibility in choosing the functions that are and will be available to them. l0 l00Base-T Ethernet The Ethernet standard is a networking technology that was developed to define wiring and signaling required in a LAN to transfer data. Ethernet became popular in the 1990s and has become the most widely used networking technology in most LANs today. The 10 100Base-T Ethernet module s name can be broken down as follows 10 100 Refers to the transmission speed that is supported by the module. The 10 refers to a transmission speed of 10 Mbps and the 100 refers to a transmission speed of 100 Mbps. This is a configurable option supporting either 10 or 100 Mbps. Base Refers to the baseband signaling. A signal is a flow of electronic information usually modulated as a time or position function. Because many lower signals are normally sent to higher signal frequencies for transmission the lower signals are considered the base hence baseband signaling. T Refers to the twisted-pair cabling that is used for this standard. 000Base-SX l000Base-T Ethernet 1000Base-SX and 1000Base-T are Gigabit Ethernet GbE standards. 1000Base-T is a GbE standard for implementing Ethernet at a speed of 1 gigabit per second. While it is not a standard for most small LAN configurations it is slowly becoming a