Campus Network Access Internet Scheme
Li Pulong
The Ministry of Education proposed in the overall deployment of the "School School" project, using 5 to 10 years to make the primary and secondary schools of 90% of the country can access the Internet, enabling primary and secondary school teachers and students to share online education resources and improve all in all Educational Teaching Quality of Primary School. Therefore, select a suitable campus network to access the Internet program, requiring campus network construction decision makers carefully. An optional access method is currently in the way the campus network is mainly: fiber, DDN, ISDN, ADSL, etc. 1. Fiber fiber is the fastest speed Internet access method, which is suitable for large-scale campus Internet Internet access to bandwidth requirements, of course its technical requirements and costs are also the highest. 2, DDN DDN is the main way of campus network access Internet, up to 2 Mbit / s. It has stable performance, moderate, compared to medium-sized campus network. 3, ISDN's small campus network for less terminals, optional ISDN access to the Internet. The standard speed of ISDN access Internet is 64kbit / s (1b D). ISDN configuration is simple, although using telephone lines like MODEM, you can call while online. 4, ADSL ADSL is the next day of the Internet access method. This is the campus network Internet access scheme recommended by the author and will be described in detail. ADSL Access Internet ADSL is an abbreviation of Asymmetric Digital Subscriber Line, meaning in which 8 Mbit / s and 1 Mbit / s are 8Mbit / s and 1 Mbit / s respectively. The ADSL Internet is also available through telephone lines, but no dialing is required. ADSL's usage fees and maintenance costs are much lower than DDN, but the speed is higher than DDN, which is ideal for campus access Internet. The ADSL device and campus LAN connection are shown in the figure, the installation and setup processes are as follows. Select a higher configuration PC in the campus network as a proxy server accessing the Internet. This PC is installed two fast Ethernet cards. One piece is connected to an external ADSL MODEM with an external ADSL MODEM with an external ADSL MODEM, and the other is connected to the campus network. External ADSL MODEM and filters are connected to the RJ-11 copper line line, and the filter is connected to the Telecommunication Bureau via the telephone. The filter is used to separate the low frequency signal with the ADSL high frequency signal. If you access the phone on the filter, the Internet and the call are both incorrect, and a telephone line is saved for the school. ADSL MODEM with G.Lite standard does not require a filter for the installation filter due to reducing the input signal, which makes the ADSL Modem installation simpler.
ADSL equipment and campus LAN connection diagram Domestic Telecommunication Bureau often uses different brands of exchange equipment, which may be extremely incompatible with different brands of ADSL MODEM. Therefore, the school should consult the local telecommunications department when purchasing ADSL MODEM. The proxy server installs the Windows 2000 Server operating system, running Microsoft ISA Server 3.0 to implement the management and control of Internet Access. The corresponding proxy service client software is installed on the teacher and the student machine. Several ADSL MODEM products ★ Shenzhou Digital DSL-300 ★ Shenzhou Digital DSL-300 is an Ethernet Adsl Modem that is suitable for primary and secondary schools and small office environments. It is equipped with a RJ-11 ADSL port and 1 10Mbps Ethernet port that provides simple and effective broadband access to meet interactive video, high speed data transfer, and Internet access. ★ Ride QL1680 ★ This ADSL MODEM 10 / 100M adaptive Ethernet port takes up less, the web configuration interface is in line with the current popular Server / Browser mode, supports various local devices.
