Wednesday, October 25, 2006

LAN Is Simple, Right?

I was in the Boston area last week at the latest LXI Consortium meeting. We spent some time the first day putting together our "lessons learned" from building a multi-vendor Ethernet-based test system. To no one's surprise, we had a couple of pages of feedback. One of the most prominent points was that the demo took three to four times the amount of effort we expected. I haven't crunched the exact numbers, but our one team-week turned into several, including some near all-night sessions. Our "team" consisted of experts from Agilent, Rohde & Schwarz, VXI Technologies, National Instruments, and others.


I'm sure those of you who build test systems for a living are laughing at us. You would have wisely planned for the extra effort, despite (or perhaps because of) the fact that we were using LAN instead of GPIB, PXI, or some other more traditional instrumentation bus.


And you'd be right to laugh at us. I think we were a little naïve.


Speaking of naïve, I had my own "IT issues" on my home network over the weekend. The parallels to an LXI system are striking...



I had a simple problem I wanted to solve: I needed more disk space.


As many of you know, one of my creative outlets is photography. Before the LXI meeting, I was in Vermont for a photo workshop with David Middleton and Rod Barbee. I brought home several gigabytes of digital images.


I've been making backups on DVDs, but they aren't very archival, and I need a lot of them to hold my images. I could have bought a simple internal or USB hard drive and been happy. But no! I had to go for a RAID network attached storage device.


In theory, this is a simple solution. The storage device is a simple device with a LAN interface. It automatically works out the network connection. There's a simple tool for discovering the device on the network, and it has a web server built in to let you configure various options. Sounds like LXI, doesn't it?


You've probably surmised by now that something went wrong. To make a long story shorter, it turns out that my new network storage device is incompatible with my network router. Both the network router and storage device are from respected companies, but somehow they started fighting over the network.


I "solved" the problem by buying a new wireless+100-Base-T $30 router. I looked at the gigabit ethernet routers, but they're about 5X the cost. Yikes!


The new router has a simple "getting started" utility, and you configure it through its web server. Sound familiar? It only took me a few tries to get it to work wired, but I'm still struggling with the wireless security.


Ethernet is just supposed to work! When I bought my storage device, I couldn't have conceived of all these hassles. I didn't budget for the extra time and equipment. Recall that I was a network administrator at an earlier point in my NI career, so I consider myself a little more savvy than most network users. Besides, I just helped build an expensive LXI test system! How hard can it be to add a storage device to my home network?


I'm up and hobbling right now, but I can't help thinking about how simple it would have been to plug in a simple USB device.


2 comments:

Bob S. said...

When I read this, I felt like I needed to find a time machine and go back to the 70's and see what it took to make the first GPIB system! Like it all works out of the box in the early revs! This is why we go thorugh such exercises! We learn before the customer has to suffer.

Brian Powell said...

So true! It took about a decade for GPIB to settle down, and only with the help of additional standards such as IEEE-488.2, SCPI, and VXIpnp.

Another "lesson learned" from the LXI system was that while much of our pain was caused by buggy implementations of the LXI specification, there wasn't anything inherently wrong with that specification. In other words, the LXI implementations will improve as vendors figure out their own weaknesses and fix them.

It should also help that LXI is built on standards that came before it, such as VXI-11, IVI, and IEEE-1588.

There are still some challenges, though. IEEE-1588 version 2 is changing things in incompatible ways. LXI vendors seem to be moving away from VXI-11 and SCPI.

We were a little naïve to expect that these early days of LXI would work as well as the more established buses like GPIB and PXI.