Juniper has some hope for showing stronger numbers, anyway, because it does appear that AT&T Inc. and Verizon Communications Inc. are starting to revive capital spending, as expected. At issue is the fact that data traffic continues to grow, and carriers that have muted their spending can't run their networks hot forever.

"I think we're about to enter a new cycle for routing growth," said Kevin Johnson, Juniper's CEO. "We had a strong quarter with our Tier 1 U.S. service providers."

That growth has tended to be on the network edge, which had an unfortunate side effect: Juniper's T4000 core router saw sales decline, officials said. (Whether that was compared with the previous quarter or previous year wasn't clear.)

The company is also claiming to be on the offense when it comes to software-defined networking (SDN). Juniper had stayed quiet on the subject during 2012 -- by choice, company officials claim -- and unveiled parts of its plan earlier this month. (See Juniper's SDN Will Build Service Chains and Juniper Buys Contrail for (More) SDN Smarts.)

As analyst Tom Nolle of CIMI Corp. notes, Juniper's plan focuses on moving more functions into software; that's a plan closer to the Network Functions Virtualization (NFV) initiative than to most definitions of SDN. (See Carriers Peer Into Virtual World.)

Even with SDN in the picture, much of Juniper's future is pinned on five relatively new products: the T4000 core router, the QFabric data-center fabric, the MobileNext evolved packet core, the PTX packet-optical transport system and the ACX access router.

Juniper is on track to make its goals for 2013 for those products, Johnson said. The company wants to get $150 million per quarter in revenues out of them, as a whole.

QFabric has been the most closely watched because it got off to such a slow start; in fact, Juniper ended up creating a smaller version because so many customers didn't want the full-blown fabric. Juniper added 130 QFabric customers during the fourth quarter, Johnson said, but it's not clear how many of those simply bought the QFX3500 top-of-rack switch, which counts as part of QFabric but doesn't imply the customer will buy the other QFabric pieces.

For its fourth quarter, which ended Dec. 31, Juniper reported revenues of $1.14 billion and net income of $95.7 million, or $0.19 per share, compared with year-ago revenues of $1.12 billion and net income of $96.2 million, or $0.18 per share.

Non-GAAP earnings of $0.28 per share were $0.06 better than the analysts' estimate compiled by Thomson Reuters.

But Juniper's first-quarter forecast could be considered light. The company expects first-quarter revenues of $1.05 billion to $1.07 billion, and analysts' forecasts average out to $1.07 billion, the top of the range.

Juniper shares were up $0.15 (0.7 percent) at $21.65 in after-hours trading Thursday.

— Craig Matsumoto, Managing Editor, Light Reading