Vonage, yet another funding round?

We have heard a lot of speculation about Vonage IPO sometime this year, but what I am hearing is that the company is out raising another big round of funding, perhaps a mezzanine round before it goes public. The rumors of this have been floating for a while, but sources are indicating that it is happening. The amount being bandied about is around $100 million. Vonage, as you might recall has raised over $200 million, and could top $250 million in venture funding quite easily. I wonder how much of a company has Jeffrey Citron had to give-up to VCs? It has to be a substantial amount!