Switching in the automated lab
By Richard A. Quinnell, Contributing Technical Editor -- Test & Measurement World, 10/1/2006
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| Roberta Gonzalez Co-founder EdenTree Technologies Courtesy of EdenTree Technologies |
Q: What is driving the trend toward communications lab automation?
A: Traditionally, there was a lot of waste and inefficiency in test equipment usage. People would hoard equipment, leaving it underutilized. As budgets tightened and test equipment became more expensive, however, this approach was not viable. Now, engineering teams are having to share equipment in a laboratory setup, scheduling equipment use to ensure efficient utilization. In some cases, engineering teams in different parts of the world use the same laboratory, controlling tests remotely, which allows the test equipment to be in productive use around the clock.
Q: How is remote usage handled?
A: Because communications test equipment is connected to the network, it has the ability to be configured and deliver captured data over the network. Engineers can even set up scripts that run a series of tests and archive the results on storage networks. What has been missing is the ability to remotely manage the connections to the network and among equipment. To handle connections in the past, laboratories have had to have staff onsite to attach cables as directed by the remote team. Now, remote switching is also possible and becoming popular.
Q: What are the characteristics of these remote switching systems?
A: One of the characteristics is a physical-layer-only functionality. The switch cannot deal with protocols; it must have the characteristics of a cable or of fiber. Otherwise, the switch will impact the measurement. Also, switches must offer an any-to-any matrix. Users want no restrictions on what they can connect together. The switches must be able to support a variety of interfaces, such as optical, copper, Ethernet, and RF.
Q: What is now making them possible and popular?
A: A lot more switching hardware has become available in the last few years, and it has become more affordable. In optical-electrical-optical (OEO) switching, for instance, there was only one major supplier three years ago. Now, there are three or four. Some optical switches have come down in price 50% over the last few years. At the same time, they have been getting larger. Not long ago, a 144-port switch was as large as you could find. Now, 288-port switches are available, while the price has lowered. This has been making switching hardware much more cost effective for lab automation.
Q: What kinds of test labs can benefit from this remote switching?
A: Any lab that needs frequent reconfiguration of its layout can benefit. This includes network test labs, interoperability labs, demonstration labs, training labs, and the like.
Q: Does switching offer other benefits besides remote test configuration?
A: With switching, test setup can be configured dynamically. EdenTree’s LabManger 5.0 software, for instance, can control access to test equipment, control power to the equipment, and configure the switch matrix based on scripts and scheduling. This allows full automation of the test. To perform regression testing, for instance, engineers can schedule a series of tests and put them in queues to run in sequence automatically, changing equipment configurations as needed.
Q: Programming these tests sounds like a challenge.
A: EdenTree’s software allows developers to graphically define the connections they desire regardless of the underlying switch technology, schedule the use and activation of equipment, and select the test scripts to run. But the software that directly controls the test equipment may lack this abstraction. Right now, teams have to write a different script for each piece of test equipment, even if the pieces perform similar functions.
There is an effort beginning that seeks to change the situation. The Internet Engineering Task Force (IETF) is establishing the Network Testing Device Protocol (NTDP) group (www1.ietf.org/mailman/listinfo/ntdp). The group is still in the stages of defining its scope, but the goal is to achieve commonality across all technologies for configuring test devices over the network.
