It shouldn’t come as a surprise, but the online video boom is helping Cisco Systems sell a lot of its top-of-the-line CRS-1 routers.

The San Jose-based router and switch maker said that the total global cumulative shipments of CRS-1 Routers have doubled in less than nine months, rising from a total of 900 units shipped through June 2007 to more than 1,800 units shipped through March 2008. This shouldn’t come us a surprise. It was back in June 2007 that irst signs started to point to video (any kind of IP video) as the savior for Cisco.

CRS-1 was first introduced in May 2004, and since then has been adopted by many large carriers including Free.fr, Comcast, British Telecom and AT&T.

Cisco predicts that the Internet video traffic will be twenty times the traffic in 2006. They made a bold (and is somewhat self serving) claim that “in 2011, online video will generate 1 billion DVDs worth of traffic each month.” (Source: Cisco’s Global IP Traffic Forecast, 2008)

Even if you discount some of those numbers as corporate hyperbole, there is no denying that Cisco will continue to sell a lot of these mega million dollar monsters.