Communication

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  Servers need to communicate, either between them or with the outside word. For inside communication, you need to go with a switch to allow the various servers to communicate with each other. Another device, a hub, can also do the same thing, but if hubs can be okay for a small home network, for a business they are not reliable enough and do not provide any way to shape the traffic, create virtual LANs or otherwise manage your Internet network.
  
  Outside communication is done through a router. Communication on your local network does not follow the same rules as the communication on the Internet. The router translates the information that comes from your local network to a format that the Internet can understand and vice versa.
  
  

Power

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  Servers and all the other equipment related to your network will need power. Plugging the server to the wall is insufficient since you would rely on the grid only for your business. The UPS (uninterrupted power supply) is basically a battery system that takes over the power supply of your server when the grid is down. The UPS can be used to provide enough power to shut down the servers manually or as a temporary power source while a backup generator starts. In any case, be sure to have a UPS system that can provide at least 10 minutes of power.
  
  

Space Management

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  While not as critical for the small or medium business as it is for big companies, space management is important. Servers are usually put in racks that slide into server cabinets. That system makes it easy to have a high density of servers in a server room. Besides a large number of servers, the physical proximity also allows you to use shorter network cables, a centralized console and easier power cord management. More advanced systems like the blade system allow for even greater density of servers.
  
  

Security

• Whether your servers are designed to serve your local network or be accessible from the outside, they need to be protected. The two main defense systems that should be present on your network are IPS/IDS and a firewall. The firewall filters all the connections to authorize only the ones that match this set of rules. The IPS/IDS (intrusion prevention system/intrusion detection system) analyzes the traffic on the network and tries to determine the intent of the traffic.
  
  For example, if a server was compromised and started sending spam, your firewall, because the rules authorize the sending of emails, would not block the spam emails. But the IPS/IDS would detect that the traffic resembles spam and would tell the firewall to block the traffic by changing its rules and/or reporting the abnormal behavior to the administrator.
  
  

Servers

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  Servers can take various shapes and forms. They can be housed in cases similar to desktop computers or use racks. Racks use the U system (unit, or 1.75 inches tall and 19 inches wide) with servers 1U and up, depending on their function on the network. Firewall servers are usually 1U, while network storage servers can be 4U to 9U, depending on the amount of storage.