How Do You Communicate with a Network Element When the Network is Down?

Given enough time, just about any computer network will eventually crash; that’s just the nature of networks. Ideally, your network shouldn’t crash on a regular basis, but when it does go down, how do you communicate with remote network elements in order to get the network up and running again? In cases like this, obviously, you can’t communicate with a problematic, router, server or switch via a normal network connection … but that still doesn’t mean that communication with a remote network device is impossible.

In order to allow access to important command functions on remote network devices, it is imperative that your network includes a secure console server that allows both in-band and out-of-band communication. Generally, “in band” refers to normal communication via your primary LAN. It’s important to note however, that “out of band” can often refer to several different means of communication; typically either communication via a parallel, back up network, or in some cases, communication via dial-up connection. But whichever out-of-bad solution you choose, the intent is still the same: to provide an alternative means for accessing command functions on remote devices when your primary network is not available.

In cases where your “out-of-band” refers to a secondary, back up network, the console server generally resides on the secondary network, but is also connected to console ports on devices that reside on the primary network. This allows you to communicate with the console server via secondary network, which then in turns provides access to console port functions on devices on the primary network. With this set-up, a network administrator can then use the console server to issue commands to a crashed network device, even when the primary network is down.

A second means for out-of-band communication involves a dial-up connection via modem. Since dial-up connections generally don’t provide the same security and authentication measures that are present when communicating via LAN, dial-up communication must rely on other methods to ensure secure communication.

Most console servers include a password feature to protect access to dial-up connections, but given the ease of hacking past a password, this is clearly not enough. This is why WTI RSM and TSM series console sever products include a “dial back” feature to provide an additional layer of security for dial-up communication. When the console server answers an in-bound modem call and the dial back feature is enabled, the unit will first prompt the caller to enter a username and password. If a valid username/password is entered, the console server will then disconnect and call the user back at a phone number that was previously designed for the caller’s specific user account.

Once a secure connection with the console server is established, an out-of-band dial-up connection performs the same function as an out-of-band connection that is established via a secondary network. After you have dialed-in to the console server, the console server then provides access to command functions on network devices that reside on the primary network, allowing you to troubleshoot or reboot connected devices, even though the primary network is down.

An intelligent console server with secure, out-of-band communication saves both time and money by eliminating the need to send service techs on long rides to remote network installation sites, just to enter a simple command or flip a power switch on and off. This ability to remotely diagnose and correct network problems effectively eliminates the need for techs to be kept on perpetual “road trips”, traveling from site to site to correct problems, and helps you to keep your techs close to headquarters, so they’ll be handy when they’re really needed.

Western Telematic, Inc. (WTI) designs and manufactures remote device management products for IT applications. WTI’s Serial Console Server products, Remote Reboot products, Switched PDU products and A/B Fallback products are engineered to allow you to securely manage and troubleshoot rack equipment in remote locations.

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