Having a well managed Computer Network Diagram of your networking infrastructure where you are responsible with, is a must for documentation. It is not just for documentation purposes, you can use this LAN Network Diagram to develop risk security assessment or develop a critical assets register.
Unfortunately not all the network administrators develop their LAN network diagramparticularly for small business or SOHO. But for medium-sized to enterprise class organizations, having a complete Computer network diagram is a must. Besides as documentation purposes, Computer network diagram can help you as the network administrators to maintain andtroubleshoot the networking problem as well as managing the network.
In the computer network diagram, all the networking devices should be identified by the IP addresses and be provided with well-managed labeling. If we are talking about the IP address, we should make a clear distinction in our LAN network diagram between the public (global) IP address and the private (internal) IP address. The private addresses must be hidden from the public network (the Internet) by a NAT mechanism configured in the firewall. Typically a firewall is a barrier or a border line between the trusted-network (our private – internal network) and the un-trusted network (the internet). Therefore the firewall must be a secured system. See also guidelines in firewalls security and the IP address classes.
Simple Back to Back Computers
The basic computer networking diagram can start with two computers which is configured in back to back. This configuration is typically used to transfer large amount of data between the two computers such as for full backup prior reinstallation of the OS platform. You can also perform full backup by using hard disk backup.
The figure 1 shows a computer network diagram for two computers configured in back to back. You need to use the UTP cross cable and connect each end of the cable into each of the NIC adapter ports (RJ-45 port). Or you can use a Switch to connect more than two computers to form a workgroup network. For connecting the computers to the Switch, you need to use the straight through type UTP cable. If your Switch supports the autosensing feature, you can use either cross or straight through network cable.
Figure 1 - Two computers network diagram
Computer Network Diagram – Share the Internet
Generally computer network diagram can be shown in the following figure. The LAN network diagram can be divided by two different networks: the private network (which sites behind the firewall) and the public network (that faces to the internet). The networking devices that sit in the public network typically consist of the CSU/DSU (which connect direct to the local loop of the Telco central office), a networking perimeter router (as the first line of defense against the internet threats), and the firewall.
Typically in home usage, the manufacturers ship the three devices into a single all-in-one product particularly for broadband internet connection such as SURFboard SBG900 by Motorola (for Cable services) or DGND3700 wireless ADSL modem router (for ADSL services). But many products ship with the function of the wireless router and the firewall separate from the modem such as Linksys E4200 N750 and WNDR4000 N750 wireless routers. Both are wireless gigabit simultaneous dual band routers with N750 technology (speeds up to 450Mbps in 5GHz band and up to 300Mbps in 2.4GHz band).
Figure 2 shows the conceptual computer network diagram that consists of private and public networks in block diagram. There are many routers with built-in modem that integrate the firewall, the router and the modem into a single device.
Please note that the IP addresses used must be different between the internal network (use the private IP address) and the public network (use the global IP address provided by your ISP).
Figure 2 - Shared internet - conceptual network diagram
In home usage, the wireless router typically has one WAN port (that connects direct to the LAN port of the modem with public IP address assignment) and 4 LAN ports with private address. The figure 3 shows a typical home wireless computer network diagram which uses a wireless router with shared printer, a modem that connects to the internet and some wireless clients including the Laptops with Wi-Fi enabled and XBOX game console with wireless adapter.
Figure 3 - Home Wireless router diagram
There several wireless routers that include a USB port that can be used to host a shared printer eliminating a print-server adapter.
Computer Network Diagram – Powerline
With the large house or multi-floor building, running the network backbone cable can be a hard work to complete. Drilling the walls to shorten the cable length or opening the ceilings to hide the clutter of the wires would be a lot of works to do. Not many users do mind with hassle of running the network cable. On other hand, building wireless network to cover the farthest corner of the building with a good signal strength is likely not possible particularly for streaming high definition media. The ideal solution for this type of network is by deploying Powerline adapter kits. See also home computer network – with powerline Ethernet adapter.
The figure 4 shows a computer networking diagram that uses Powerline adapter kits. The first floor where you build a wireless network, you connect the wireless router to the modem to share the internet. By adding a Powerline adapter connecting to the router Ethernet port, you enable the electrical wiring within the building as the virtual transmission medium for the network. Add a Powerline adapter with multi-port Ethernet in the second floor to let you join the home theater devices including XBOX, Blu-Ray player and HDTV to the internet.
Figure 4 Computer network diagram using powerline AV adapter
Redundant Computer Network Diagram
In medium to enterprise-class LAN network diagram, the computer network diagram is very complicated which might contain VLANs, redundant links, and sometimes contains multiple DMZs behind the firewalls.
The figure 5 is the example of the computer network diagram which contains redundant links for WAN connections, and also redundant links for each of the uplink switches.
Figure 5 Redundancy computer network diagram
In the above computer network diagram, the uplink switches are supplied from different two core switches. All the switches must be STP enabled if you configure multiple switches redundantly to avoid broadcast storm. See also STP protocol for more detail about Spanning tree protocol.
If you also configure multiple VLANs, in your LAN network diagram should mark each of the computers with each VLAN IDs. The use of layer 3 Switching will improve the performance of the LAN network if the VLANs are implemented. See more detail VLAN tutorial about VLAN ID.
In large networks, computer network diagram helps you to identify the critical items within the network, and you can make additional control for future disaster recovery. See also business continuity and disaster recovery plan and example of risk assessment.
