Sonus Networks ( SONS) rose Monday afternoon after posting solid fourth-quarter numbers.The Chelmsford, Mass., voice-over-Internet-protocol equipment maker posted net income of $5 million, or 2 cents a share, on sales of $57.2 million in the quarter ended Dec. 31. Those numbers compare with a profit of $6.3 million, or 2 cents a share, on $45 million in the year-ago quarter. Analysts were looking for earnings of a penny a share on $50 million in sales, according to Reuters Research. CEO Hassan Ahmed said in a press release that 2005 "was a strong year for Sonus, culminating with robust revenue, order and shipments growth in the fourth quarter." Sonus shares rose 16 cents to $5.58 in after-hours trading Monday.