Home > Resources > Technical Resources > Black Box Explains > Networking > What is a Terminal Server?
What is a Terminal Server?

What is a Terminal Server?

Black Box Explains

IT infrastructure is mission-critical for many global corporations today. Network downtime can result in huge financial losses in the short and long term when companies lose the ability to operate, communicate or process payments. In extreme cases, some businesses never recover from unplanned outages.

To ensure uptime and mitigate potential losses, businesses need the ability to troubleshoot their network equipment as quickly as possible. Smaller entities with a single server room nearby can address issues fairly easily using on-site personnel. For large corporations with hundreds or thousands of locations, however, it is cost prohibitive to staff IT personnel at each site. Sending someone out when there is an issue is costly in terms of travel as well as extended downtime. Remote management through terminal or console servers can be an effective solution that offers a combination of speed and cost savings.

What is a Terminal Server?

A terminal server (sometimes called a serial server) is a hardware device that enables you to connect serial devices across a network. They establish user connections coming from a serial port out to the network ports.

Terminal servers acquired their name because they were originally used for long-distance connection of dumb terminals to large mainframe systems such as VAX™. Today, the name terminal server refers to a device that connects any serial device to a network, usually Ethernet. In this day of network-ready devices, terminal servers are not as common as they used to be, but they're still frequently used for applications such as remote connection of PLCs, sensors, or automatic teller machines.

The primary advantage of terminal servers is that they save you the cost of running separate RS-232 devices. By using a network, you can connect serial devices even over very long distances—as far as your network stretches. It's even possible to connect serial devices across the Internet. A terminal server connects the remote serial device to the network, and then another terminal server somewhere else on the network connects to the other serial device.

Terminal servers act as virtual serial ports by providing the appropriate connectors for serial data and also by grouping serial data in both directions into Ethernet TCP/IP packets. This conversion enables you to connect serial devices across Ethernet without the need for software changes.

Because terminal servers send data across a network, security is a consideration. If your network is isolated, you can get by with an inexpensive terminal server that has few or no security functions. But if you're using a serial server to make network connections across a network that's also an Internet subnet, you should look for a console server that offers extensive security features.

Remote Network Management Software

Network management software programs such as Openview or SolarWinds allow administrators to access network devices remotely. Remote Network Management Software is designed to operate across a wide range of equipment—such as PCs, printers, servers, switches, routers and wireless access points—from many different vendors. Software solutions can monitor the status of all devices and communicate distress messages, often using SNMP. Administrators access the network though a dashboard from any web-enabled device to monitor network availability and performance.

There are many network management software solutions but a strong limitation of them is that they may lose connectivity to devices if the network is not running properly. If a switch fails, for example, you will likely lose the ability to communicate with it. If your Ethernet goes down, you could lose access to your entire network—along with your ability to do business.

Out-of-Band Management with Console Servers

Out-of-Band Management with Console Servers

For improved network availability and remote trouble shooting capabilities, corporations often augment NMS programs with an out of band management solution. Console servers give system administrators access to a failed device through an out-of-band connection (OOB). OOB availability allows you to access your network devices even if your network is down, via the internet, 4G cellular service or POTS—the plain old telephone service. This solution uses standard programs such as SSH/Telnet and HTTPS. A console server is a hardware appliance that connects, via RS-232 serial ports, to your switch, router, firewall, server, PBX, UPS or PDU on one end and to your Ethernet port on the other end. One console server may have as many as 48 serial ports. Console servers are often connected to another network separate from your data network, so even if your primary network is down you can still troubleshoot, reboot, reconfigure or reimage any managed device in your system.

Virtual Central Management System

Black Box's console servers can be managed using a Virtual Central Management System (VCMS). VCMS offers centralised, secure, end-to-end OOB management and proactive alerting regardless of remote WAN or LAN health status. The VCMS portal enables you to manage large numbers of console servers over a wide geographic area, even globally, from a single screen. You can search managed devices by name, no matter how they're connected, and sort results by geography, application or managed device type. VCMS gives you the ability to pinpoint failed devices and address issues quickly, minimising downtime and the impact on your operations.

Another advantage of VCMS is its scalable administration and automation, from day one provisioning to routine operations and disaster recovery. Even networks with thousands of servers, switches and routers and hundreds of console servers can be managed from anywhere from a single, secure portal.

What is a Console Server and how does it work?

Console Servers provide a number of serial ports that connect to the console ports of active network devices. Console Servers allow remote access to crucial IT infrastructure including servers, switches and routers in data centres and distributed environments. Usually they include Secure Shell (SSH ) access which is a network protocol for operating network services securely over an unsecured network. Some console servers have multi-functionality such as log all data of the serial ports, trigger events, follow intelligent rules, send email notifications and redundant Ethernet ports for joining several networks.

Benefits of Console Servers

Console servers can save you time and money by ensuring high availability of your IT systems and safeguarding your business continuity. Remote management and troubleshooting provide for quick disaster recovery after power outages, and they eliminate the need to send personnel on-site in response to issues—saving you additional costs in time and travel. For security, OOB management integrates with VPN and authentication systems and extends enterprise security policy to distributed assets. Console servers are also a scalable solution. Regardless of the size of your network, you can access devices, monitor status and troubleshoot issues from anywhere through a single VCMS portal.

When to consider buying / updating a Console Server?

Console servers are a good solution for large distributed enterprises with multiple branches — such as banks, insurance companies, hospitals, utilities, military divisions and school systems — that do not have servers and IT staff on-site. Within these enterprises, certain events create opportunities to include console servers in the network infrastructure.

    You should usually consider buying / updating a Console Server when:

  • You are planning a new LAN in a new building
  • You are conducting a complete forklift upgrade to a new network for enhanced capabilities, such as supporting VOIP phones
  • You would like to increase network availability by adding a network management system
  • A costly network outage has shown you that your existing situation is vulnerable, and you would like to improve your business continuity
  • A corporate merger or acquisition requires combining two or more networking systems into one

Learn More about Console Servers

If your distributed enterprise demands high network availability for mission-critical infrastructure, out-of-band management with console servers is an excellent enhancement to your NMS system. For more information, contact Black Box's Tech Support centre.

Related Products