* Launches $5 bln three-part debt sale

* Cisco cash rich, but most of it overseas

* Cisco stepping up M&A, plans to buy Starent for $2.9 bln (Adds background on Cisco's M&A strategy, analyst comment)

NEW YORK, Nov 9 (Reuters) - Top U.S. network equipment maker Cisco Systems (CSCO.O: Quote, Profile, Research) on Monday launched a $5 billion three-part debt sale, showing the company replenishing its war chest as it steps up acquisitions.

While Cisco is cash rich, with $35.4 billion in cash and investments at the end of the last quarter, most of it was overseas as a result of its global operations, with only $4.7 billion held in the United States.

"Moving cash into the United States from international geographies might trigger adverse tax implications, so a debt raise could make sense," said Taunya Sell, an analyst at Ragen MacKenzie, a division of Wells Fargo, in a note to clients.

She said proceeds were likely to be used to fund Cisco's planned acquisition of wireless equipment maker Starent Networks Corp (STAR.O: Quote, Profile, Research) for $2.9 billion.

Cisco has said it plans more acquisitions ahead. It is also planning to buy Norwegian videoconferencing company Tandberg ASA (TAA.OL: Quote, Profile, Research), although that deal will use overseas cash.

IFR, a Thomson Reuters service, said the latest offering consists of $500 million of five-year notes launched at 67 basis points more than comparable U.S. Treasuries, and $2.5 billion of 10-year notes launched at 100 basis points more than Treasuries.