Investing in Juniper Networks (Nasdaq: JNPR) is becoming something like a roller-coaster ride, as the stock bounced from $32 a share in April to $22 per stub in July -- and now is right back above the $32 mark again. What gives?

Last night's third-quarter report helped Juniper over the $32 line thanks to reasonable sales and great earnings. The company is growing earnings faster than arch rival Cisco Systems (Nasdaq: CSCO) although it remains a less efficient operator with net margins lagging far behind Cisco's. To some, that's a sign of weakness; to others, an opportunity for Juniper to tighten up its operations and juice up the bottom line that way. That see-saw interplay is exactly the kind of uncertainty that often leads to high volatility.

Even so, Juniper's mood swings are a bit extreme. I mean, Rambus trades higher or lower based on the luck of the draw in patent lawsuits and licensing deals. TriQuint Semiconductor (Nasdaq: TQNT) shows a high beta value because big design wins in the smartphone market have boosted that stock to all-time highs. These are legitimately tough issues to call from the sidelines, and it makes sense for TriQuint and Rambus to go on rocky chart rides.

Juniper is in a different boat, because networking is in generally high demand and will be for years to come -- maybe even decades. The ups and downs here are due to varying levels of investor confidence in the company's ability to execute. Cisco has no such issues, which combines with operations on a larger scale to make a more stable investment. Similarly JDS Uniphase (Nasdaq: JDSU), which supplies optical components to the networking industry, has management issues in spades and hasn't always had a clear focus thanks to being the result of a series of dot-com mergers. This has resulted resulting in bad margins and plenty of uphills and downhills.

While this quarter was stronger than the year-ago period, I don't see any kind of steady improvement in Juniper's numbers over the long haul. Speculate in this stock or Juniper if you must, but be aware that you are, indeed, speculating.

Fool contributor Anders Bylund holds no position in any of the companies discussed here. The Fool has written calls (bull call spread) on Cisco Systems. Try any of our Foolish newsletter services free for 30 days. True to its name, The Motley Fool is made up of a motley assortment of writers and analysts, each with a unique perspective; sometimes we agree, sometimes we disagree, but we all believe in the power of learning from each other through our Foolish community. You can check out Anders' holdings and a concise bio if you like, and The Motley Fool is investors writing for investors.