Updated from 8 a.m.

Juniper ( JNPR) shares jumped 12% Wednesday after the networker won rave reviews for its second-quarter numbers.

The telecom equipment company also boosted third-quarter guidance and set a $250 million stock buyback. But Juniper surprised investors late Tuesday by saying on its conference call that finance chief Marcel Gani would give up his job at the end of the year. Gani will stay with Juniper in a different but otherwise unexplained role, and Juniper didn't name a successor.

For its second quarter ended June 30, the Sunnyvale, Calif., maker of gear for phone networks posted a pro forma profit of $42.7 million, or 8 cents a share. That figure, which excludes certain costs, is up from $13.6 million, or 3 cents a share, a year earlier

The latest-quarter pro forma figures doubled the Wall Street analyst estimate. Using generally accepted accounting principles, the latest quarter showed a loss of $12.6 million, or 2 cents a share.

Revenue surged 86% to $307 million in the latest quarter. That's some 10% north of the analyst consensus estimate shown by Thomson First Call.

"We met our financial objectives, exceeded our goals for integration of the NetScreen acquisition, expanded our partner and channel relationships, all while remaining intensely focused on our customers and their needs for secure high-performance network solutions," CEO Scott Kriens said.

Wall Streeters were amply impressed.

"This was a lot stronger than even some of the optimistic expectations we had seen for the quarter," says American Technology Research analyst Albert Lin, who rates Juniper a buy. "Juniper is lucky to be in IP routing, which is a very hot area both in businesses and in telcos."

Juniper, whose shares have been hit hard this year after a fast start, surged $2.71 to $24.71 in early Wednesday trading.

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