Serial over Ethernet – an enduring foundation

When I co-founded Opengear, one of the challenges for me and my engineering team was to reduce hardware cost of infrastructure management in the data center dramatically. The initial result, our CM4008, was introduced in 2005. At sub $500 for eight secure consoles (when other products cost three or four times more, some with little or no security) we helped make secure console management affordable.

With our new ACM5500 line we are now seeing this first child CM4008 being overshadowed by more powerful (but still very cost effective) younger siblings. So it is timely to reflect back on the evolution of serial console management and out of band connectivity.

Terminal Server

Serial communications (usually RS-232), arrived in the 1960s and still thrives in the 21st century. Local Area Networks entered during the 1980s allowing computer systems and peripherals to communicate over a shared medium within a building. I entered the IT scene when these two standards conveniently met in the early 1980s in the form of the terminal server, originally developed by Digital Equipment Corporation (DEC – now HP).

Users operating “dumb serial terminals” could access applications on
minicomputers and share printers. They were cool devices since they could multiplex serial links over Ethernet using existing protocols (TCP/IP) and connectivity applications (Telnet, rlogin, etc). Branch offices could access the central site through a local terminal server with a modem link.

As terminals were replaced by PCs and minicomputers by servers (Novell, UNIX, NT) the death of RS-232 seemed imminent. However it was still essential for dial-up modem connections. ISPs needed to terminate thousands of modems to connect users to the Internet using a high-speed leased line. My team (along with our competitors) created communications servers supporting dial-up modems connected to serial ports and an Ethernet connection to the network. Thus the dial-up networking market was born. But its heyday ended when ADSL/cable overtook dial-up for consumers and ISPs installed fiber pipes.

Enterprises soon found intranets and public Internet access became critical to their business. Their IT infrastructure (servers, switches, routers and storage) was growing. Vendors conveniently provided management access to hardware via – what else – an RS-232 serial port or console. This was used to log messages and enable reconfiguration of a core device that had lost connectivity. However it was impractical to manage tens to thousands of consoles.

Console ServerAdministrators used aging terminal servers to solve the scalability problem by using them in reverse to access consoles across the network (in band). Thus the DIY serial console server was born. The industry then embedded security in the form of SSH, authentication, logging of sessions, and email or SNMP notification of messages and the “Secure Console Server” market was established.  Some products also allowed remote access via dial-up modems in the event of a complete network outage (i.e. Out Of Band).

Today, secure console servers are 1RU devices mainly installed in data centers managing the iron that powers cloud based computing. These DCIM devices have been engineered to support “five-nine” high-availability DC infrastructure demanding multiple network and power paths.

Opengear’s initial CM4000 console server had made it possible for every site to afford secure console management. The next engineering challenge was “create a highly-available, advanced console server with  the widest range of embedded out-of-band connectivity enabling management of serial and IPMI/Lights-Out consoles, power cycling, back-up and sensors!”

Opengear IM4200 infrastructure managerThe resulting IM4200 family incorporates an embedded V.92 modem, dual network and power, 16GB storage, optional Wi-Fi and embedded cellular 3G (GSM, CDMA, HPSA and EV-DO) plus dual USB and sensor ports – at half the price of other vendors. A mix of OSS (NAGIOS, NUT, Powerman) and in-house monitoring systems are integrated for event, power and environmental management.  The newest innovation is Opengear’s automated response system (ARMS) that can restore services to managed devices without operator intervention.

Our engineering team has built upon the foundation of “serial over Ethernet” and developed next generation solutions that securely monitor, manage and recover critical assets across the globe. The evolution of these products continues, of course. Recently, embedded cellular has overtaken dial-up as the preferred method for out-of-band access, and we begin to see USB making a claim as the alternate for console connection.