Campus Multi-lan Interconnection

Many small and medium-sized schools still have no interconnection between multiple LAN networks. The author of this article uses a cheap 10base5 connection method to solve the problem that can be solved through common optical fiber. This method is suitable for connecting the LAN within 2500 meters. The two ends are connected through the windows 2000 soft route, so that the bandwidth of 10 m is fully utilized. Perhaps this old-fashioned method can inspire schools with insufficient funds to achieve multi-lan interconnection.

I. Fish and bear's paw?

Recently, my friend asked me to help him connect the campus network of the school with the LAN of the teacher's residential building. The nearest node between the campus network and the LAN of the instructor's residential building is 650 meters. In the past, the school planned to use fiber optic cables to connect the LAN computers in the teachers' residences through the ADSL high-speed Internet connection on the campus network, but they were not interconnected due to the high cost, so I hope I can help him find a solution. Speaking of this, I think of the commonly used 10-base5 connection method. 10-base5 is the original Ethernet standard. It uses a 50-Ohm coarse coaxial cable with a diameter of 10mm and a bus topology, the interface of the site Nic is the DB-15 connector, through the AuI cable, with a Mau device tied to the coaxial cable, the end is connected with a resistance of 50 ohm/1 W (one end is connected to the ground line of the electrical system). Each CIDR block can have 100 sites and each CIDR block can have a maximum distance of 500 m, the Network diameter is 2500 m, which can be composed of 5 m long network segments and 4 repeater. Use the 10 m transmission rate of the baseband to transmit data using the Manchester encoding.

Ii. hardware Installation

I first listed the materials required for the project: two servers, two 3Com 3c905b-combo NICs, two 10base5 lightning arresters, and a 10base5 repeater (because there are only two 10base5 nodes, therefore, the Terminator is not required ). We first looked for two computers with NICs of the Pentium II model not used by the school, and inserted the 3Com 3c905b-combo Nic into the idle PCI slot of the computer, then, a repeater is used to connect two 350-meter coarse coaxial cables (AUI cables, 0.25 inch). One end is on the campus network and the other end is on the teacher's residential LAN, at both ends of the AuI cable respectively DB-15 port, insert 10base5 with lightning arrester, and finally from the lightning arrester led to the DB-15 port inserted 3Com 3c905b-combo Nic corresponding to the DB-15 port, physical connection to this end.

3. Configure the server

Based on actual needs, I decided to make the two Pentium II computers into a Windows 2000 soft route, which can effectively avoid lan network storms and broadcast storms, so that the bandwidth of 10 m is fully utilized. First, install Microsoft Windows 2000 Advanced Server with SP2 & spr1 on the two computers, and set the IP addresses to 10.10.10.10/24 and 10.10.11.10/24 respectively; 10.10.10.11/24 and 10.10.11.11/24. Then, find Routing and Remote Access in the "Administrative Tools" of the two servers, right-click the computer name, and select "configure and enable Routing and Remote Access ", in the configure and enable Routing and Remote Access Installation Wizard, select "network router", select the TCP/IP routing protocol, and disable "request dialing ", set the default gateways of the campus network and the teacher's residential LAN to 10.10.10.10 and 10.10.11.11 respectively. Now, the Windows 2000 soft route can work normally.

4. Configure the client

Finally, we solve the problem of high-speed Internet connection through campus network ADSL for the LAN client of the instructor's residential building. The client of the campus network can automatically detect the Internet connection shared by the LAN without any settings. The LAN client of the instructor residential building cannot normally share the Internet connection of the campus network. This is because the router filters out all the "broadcast frames", and the client of the instructor residential building cannot use the broadcast method to find Internet sharing in the campus network. What should we do? You can specify it if it cannot be found! The problem is solved by manually specifying a gateway address on the LAN client of the instructor's residential building. Take Windows XP as an example: in network connection, right-click the network adapter, select "properties", double-click "Internet Protocol (TCP/IP)" on the General tab, and click the [advanced] button, add a new gateway to the default gateway.

In this way, we have successfully achieved the interconnection between multiple LAN in the school, which is both economical and practical, and has a good effect in actual use.