Case teaching requirements:
Master the basic method of designing a large-scale campus network with three-tier structure, and design the network topology for the campus network of Nanchang University School of Software under the same conditions.
Learn to choose the right equipment to build a network.
Case teaching environment: P C 1 set, Microsoft Visio 1 set.
Demand analysis
The university campus network adopts three-layer structure design: 10 Gigabit Ethernet is selected as the high-speed backbone network connecting the four campuses of the university; Choose Gigabit Ethernet as the backbone of each campus to form the convergence layer of the university campus network; Choose 100 Gigabit Ethernet LAN as the basic access form.
The university campus network has a unified interface with the Internet, that is, it is connected to CERNET, a China education and research network, through 100 Mbps Ethernet.
1. Due to the specific mainstream technology of the network in a period of time, most of the campus networks built in recent years adopt gigabit-to-building and 100-megabit-to-LAN/desktop Ethernet solutions. This structure is actually a two-layer network topology, in which Gigabit constitutes the backbone of convergence layer and 100 Gigabit to LAN/host constitutes the access layer. Therefore, a natural solution is to choose 10 Gigabit Ethernet as the whole core layer to form the backbone of the campus network. The backbone of the campus network adopts the public network address of the Internet.
Why choose a 10 Gigabit switch to interconnect all campus networks instead of high-speed routers?
All campus networks adopt Ethernet technology systems with good compatibility.
Colleges and universities will carry out multimedia applications such as teaching video observation and remote lectures on campus network, which needs to provide high-speed information channels. 10 Gigabit switch is a three-layer switch with routing function, which can have better performance in campus network environment.
Price factor.
3. According to the analysis of the School of Software of Nanchang University, the number of IP addresses obtained by the campus network from CERNET can't meet the demand, and it can only be used to release information and contacts to the Internet or conduct network research. Therefore, the main body of the campus network IP address is the private network address converted by NAT. The use of private network addresses is not conducive to academic exchanges with other universities, but it is also a last resort; On the other hand, it may make the campus network less invaded by hackers.
4. Because of the large scale of the network, considering the future scalability, OSPF is chosen as the routing protocol.
5. Considering the manageability of the equipment, SNMP is selected as the network management protocol.
(2) Design scheme:
1, public network part
Campus network is divided into public network and private network. Connect the demilitarized zone where various application servers are placed through the firewall, and connect CERNET through the router.
The core layer of the three-tier campus network structure is located in the public network part, and Cisco's 10 Gigabit switch Cat6509 can be selected.
Lease bare fiber core of telecom company, and connect 4 10 Gigabit switches in 4 parks into a ring at 10 Gigabit rate. In order to improve the reliability of the network, campus 2 and campus 4 are also connected by gigabit optical cables.
The Core Layer Structure of Campus Network
2. Private network part
Each campus network can basically maintain the original two-tier network architecture and use dedicated IP address blocks in its own campus network. Considering the connection between the backbone Gigabit main switch in convergence layer and the university 10 Gigabit switch through the firewall, it is noted that some 10 Gigabit switches may have built-in firewalls. At the same time, they can set up their own demilitarized zone at the internal firewall and place the college's network application server.
The connection between a university network and the 10 Gigabit core layer backbone network of newly-built universities. Among them, the network backbone of Computer College consists of switch 4007 of 3COM company and gigabit optical cable connected with switch 3C 16980, and 100 Mbps Ethernet is used as the access network to connect with user PC.
(1) There are 300 ~ 1000 PCs in the campus of each secondary college, which can be divided into several subnets or VLAN when necessary to isolate the broadcast traffic, improve the network work efficiency and improve the security.
(2) Select SNMP as the network management protocol.
(3) The campus network is divided into two parts by the firewall, one is the public network directly connected with CERNET, and the other is the private network, which is the part we designed above. The adopted address can adopt the corresponding scheme designed in section 7.5. 1.