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SPOTO will introduce some ways of designing the network topology, and it helps millions of candidates master the skills. The following contents will be helpful to you.
Small star network structure design example
The star network is mainly based on a relatively inexpensive twisted pair cable. Each end of the network cable uses an RJ-45 crystal head as a network connector. The small star network referred to here refers to a star network with only one switch (or a hub, of course, but rarely used before), mainly used in small independent office enterprises and SOHO users. The number of users that can be connected to such a small network is generally around 20, of course, there are switches that can connect up to 40 users, such as 48, depending on the number of ports available on the switch.
1. Network requirements
All network devices are connected to the same switch.
There is no performance bottleneck across the network.
There must be some room for expansion.
2. Design ideas
(1) Determine the total number of network devices
This is the basis for the design of the entire network topology because a network device needs to connect at least one port, once the number of devices is determined, the total number of ports required for the switch is determined. The network devices referred to here include workstations, servers, network printers, routers, and firewalls that all need to be connected to the switch. The total number of devices in this example is less than 20 workstation users + one server + one broadband router + one network printer = 23. According to the calculation result, 24 ports are the minimum requirements, and the switch in this example has 24 1 O/1 00 Mbps ports, two 1 O/1 00/1 00 Mbps ports, and a total of 26 ports, which can satisfy the network. Connection requirements, but it is best to choose a switch with a larger number of ports.
(2) Determine the switch port type and number of ports
Generally, mid-range Layer 2 switches provide two or more types of ports, such as 1 O/1 00 Mbps and 1 O/1 00/1 00 Mbps in this example, all using twisted pair RJ-45 ports. Some also offer a variety of fiber optic interfaces. The reason for providing so many different types of ports is to meet the bandwidth requirements of different types of device network connections. Generally, the network bandwidth required for servers, border routers, lower-level switches, network printers, special user workstations, etc. in the network is high, so it is usually connected to the high-bandwidth port of the switch. The server in this example is the heaviest workload, directly connected to one of the switch's Gigabit ports (the other is reserved for network expansion); the bandwidth requirements of other devices are not very obvious (the broadband router is currently The egress bandwidth is limited by the connection line, generally within 10 Mbps, so there is no need to connect a high-bandwidth port in the LAN port. Other enterprise-class routers are different. Just connect to the normal 1 O/100 Mbps fast self. Adapt to the port.
(3) Retain a certain port required for network expansion
The network expansion of the switch is mainly reflected in two aspects: one is for the port connected to the lower-level switch, and the other is for the workstation user to connect to the subsequent addition. In connection with the lower-level switch, it is generally carried out through a high-bandwidth port. After all, the users connected to the lower-level switch are all connected through this port. If the switch provides an Uplink (cascading) port, you can use this port directly, because it is a specially processed port, and its available backplane bandwidth is wider than the average port. However, if there is no cascading port, it can only be performed through the normal port. In this case, in order to ensure the connection performance of the user connected to the lower-level switch, it is better to select a port with higher bandwidth. In this example, a dry megabit port can be left for the extended connection. Of course, in actual work, this high-bandwidth port can still be fully utilized, but it can be re-emptied when needed.
(4) Determine the total number of connectable workstations
The total number of switch ports is not equal to the number of workstation users that can be connected, because some ports in the switch are also used to connect network devices that are not workstations, such as servers, lower-level switches, network printers, routers, gateways, bridges, and so on. In this example, there is a dedicated server, a broadband router, and a network printer in the network, so the total number of workstations that can be connected to the network is 26 (24 1 O/1 00 Mbps ports + 2 1 O/ 1 00/1 00Mbps port) A 3=23. If you want to reserve a port for network expansion (maintaining an expansion port in a small network is basically sufficient, because there is also a cascade port Uplink for cascading subordinate switches on a general switch), you can actually connect The maximum number of workstation users is 22.
3. Design steps
After understanding the basic ideas of network topology design, the next specific design steps are very clear. In this example, the network user and switch specifications have been fixed, and now it is necessary to design a practical small office network solution based on these existing conditions. The method described here is still a manual drawing method. Specific steps are as follows.
(1) First, determine the critical device connection, connect the devices that need to be connected to the high-bandwidth port to the available high-bandwidth ports of the switch. In this example, the switch icon (obtained from the element map accumulated by itself or obtained through specialized topology software) is placed at the center of the designed platform, and then a server is connected to the switch with a 1 O/1 00/ Connect the 1 000 Mbps ports and label their port types, as shown in Figure 3-8. Of course, this requires the server's Ethernet network card to support the twisted pair Gigabit Ethernet standard. Because the switch has only one Gigabit port available (the other is reserved for reservation), in theory, it is only necessary to connect the most critical network server as a critical device to a high-bandwidth port.
(2) Connect all workstation user computer devices and network printers to the switch's 10/1 00 Mbps port.
(3) If the network system is to be connected to other networks through a router (such as the broadband router to connect to the Internet in this example), it is also necessary to design an Internet connection. The connection between the router and the external network is through the WAN port of the router. Although there are many types of WAN ports for routers, the WAN ports provided by broadband routers are basically ordinary RJ-45 1 0/1 00 Mbps Ethernet ports, which can be directly connected to Internet broadband devices.
Through the above simple three steps, the simple small office star network structure with only one switch device is designed. It can be seen from this that the whole step is very simple. The most important thing is to have clear ideas and connect devices with different bandwidth requirements to the corresponding types of ports on the switch to ensure that the entire network will not have performance bottlenecks. The other one, when selecting a switch, be sure to note that the number of ports must be greater than the total number of network devices that need to be connected to the switch on the existing network because a certain number of ports are reserved for future expansion.
