Is there a market for Internet Protocol telephony? Must be.

Cisco reported Thursday that it passed the 2 million mark in shipping IP phones. No. 2,000,000 went to SouthTrust Corp., one of the nation’s top 20 bank holding companies.

Cisco introduced its IP phones in 1999, and since then the company said it has replaced thousands of standard PBX exchanges in businesses.

Zeus Kerravala, vice president of enterprise infrastructure at the Yankee Group, said the number of sales “signifies that IP telephony is becoming a mainstream technology throughout business organizations worldwide and solidifies Cisco’s position as the leader in this fast growing market.”