More Videos:

3 Tech Stocks Spiking on Big Volume

Tickers in this article: ALLT UNXL VCRA
WINDERMERE, Fla. ( Stockpickr) -- Professional traders running mutual funds and hedge funds don't just look at a stock's price moves; they also track big changes in volume activity. Often when above-average volume moves into an equity, it precedes a large spike in volatility.

Major moves in volume can signal unusual activity, such as insider buying or selling -- or buying or selling by "superinvestors."

>>5 Rocket Stocks to Buy in February

Unusual volume can also be a major signal that hedge funds and momentum traders are piling into a stock ahead of a catalyst. These types of traders like to get in well before a large spike, so it's always a smart move to monitor unusual volume. That said, remember to combine trend and price action with unusual volume. Put them all together to help you decipher the next big trend for any stock.

With that in mind, let's take a look at several stocks rising on unusual volume today.

>>5 Stocks Poised to Pop on Bullish Earnings

Allot Communications

Allot Communications (ALLT) provides IP service optimization, monetization and personalization solutions for mobile, fixed and wireless broadband service providers and enterprises. Its products include Allot NetEnforcer and Allot NetXplorer. This stock is trading up 2.6% at $14.22 in recent trading.

Today's Volume: 1.11 million

Average Volume: 766,181

Volume % Change: 143%

This morning's news that Oracle ( ORCL) has agreed to buy Acme Packet ( APKT) has triggered a speculative rally in shares of other companies that make IP networking hardware, including Sonus Networks ( SONS), Procera Networks ( PKT), Broadsoft ( BSFT) and Allot.

>>5 Stocks Insiders Are Scooping Up

From a technical perspective, ALLT is ripping higher here right above some near-term support at $13.32 with above-average volume. This stock has been trending sideways for the last month, with shares moving between $13.15 on the downside and $14.38 on the upside. This move has started to push shares of ALLT above the upper-end of that recent range. At last check, shares of ALLT have hit an intraday high of $14.66 and volume is well above its three-month average action of 766,181 shares.

Traders should now look for long-biased trades in ALLT as long as it's trending above $14.38 to $14.66 with strong upside volume flows. I would consider any upside volume day that registers near or above 766,181 shares as bullish. If ALLT can maintain that trend, then this stock will set up to re-test or possibly take out its next major overhead resistance level at around $16.50. Any high-volume move above $16.50 will then set up ALLT to re-fill some of its previous gap down zone from January that started at $19.42.

Vocera Communications

Vocera Communications (VCRA) provides mobile communication solutions focused on addressing critical communication challenges facing hospitals. This stock is trading up 1.7% at $26.53 in recent trading.