Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of Finisar (Nasdaq: FNSR) rallied close to 17% before closing up 14.5%, riding on the coattails of Cisco's (Nasdaq: CSCO) strong earnings report.

So what: Several optical-networking stocks rose. JDS Uniphase (Nasdaq: JDSU) and Ciena (Nasdaq: CIEN) each soared about as much as Finisar, presumably on the idea that a resurgent Cisco is reflective of industrywide demand for fast data delivery gear.

Now what: Finisar could benefit more than most as a supplier for Cisco's own branded optical-networking equipment. There’s no guarantee, of course; but I get the reasoning behind the rally. Do you agree? Disagree? Weigh in using the comments box below.

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