Finnish network equipment maker Nokia is in talks to buy Juniper Networks Inc, CNBC reported on Wednesday, citing sources. The offer would value the U.S. network gear maker at around $16 billion, CNBC said, citing one of the sources. Juniper had a market capitalization of around $11.26 billion as of Wednesday’s close.

The Sunnyvale, California-based company’s shares soared 18 percent to $35 in extended trading. Nokia has been building its telecom equipment business after it sold its mobile phone unit to Microsoft Corp.

It bought Alcatel-Lucent for about $17 billion last year that gave it a larger fixed-line network business and made it less dependent on mobile broadband. Juniper and Nokia were not immediately available for comments.