Xylan Corp. shares fell 14% amid concern that fourth-quarter earnings will fall short of analysts' estimates. Shares of the Calabasas-based company fell $5 to $31 on Nasdaq before trading was halted at midafternoon. Earlier, the stock touched $29.75, a 52-week low. Slightly more than 1.93 million shares changed hands, nearly four times the three-month daily average of 504,000. The company, which makes computer networking equipment, said it doesn't know why its stock trading was halted. It said analysts' earnings estimates are in line with its expectations. Analysts expect fourth-quarter per-share earnings of 11 cents. Chairman and Chief Executive Steve Kim issued a statement saying the firm anticipates reporting results that are in line with analysts' estimates and that it has no reason for concern about results for the first quarter of 1997.