Avaya is close to going private in a buyout deal with Silver Lake Partners and the Texas Pacific Group for $8 billion, according to news reports.

In what would be the largest private-equity buyout of a network company, Avaya may reach a deal to be acquired Monday, with the buyers paying around $17 per share of Avaya stock, the New York Times reported. Avaya’s shares closed Friday at $16.08. Reports also say Nortel may still offer a counter bid for Avaya.

Avaya and Nortel spokespeople said the respective companies do not comment on speculation or rumor.

Last week, speculation grew that Avaya would go private, either through a private-equity buy, or in an acquisition by Nortel or even Cisco. Some observers questioned the product overlap and massive integration costs that might come with an acquisition by competitors. Now a private-equity buyout seems more likely.

Avaya made $5.2 billion in revenue and $220 million in profits in its last fiscal year, and is worth $6.2 billion overall. In the first quarter of 2007, Avaya was the leader in worldwide enterprise telephony revenue, which includes IP and TDM phone equipment, with 19% of the $2.1 billion market, according to Synergy Research Group. Cisco was second with 16% while Nortel was third with 13%.