EZchip is having a hard time closing its deal with Mellanox, thanks to some shareholder activism, which has led to a postponement of today's shareholder vote.

Instead, Mellanox proposed a revision that would give EZchip a 30-day period to shop itself around. In return, EZchip would waive its right to a termination fee if the deal collapses.

The deal, which has been on the table since September, has Mellanox offering $25.50 per share for EZchip. It adds up to $620 million when you subtract EZchip's cash.

EZchip sells the packet-processing chips that do all the heavy lifting in a router. Cisco and Juniper have tended to design their own chips, but EZchip has found inroads into both companies over the years. That might be one factor that attracted Mellanox, which sells switch chips and other Ethernet hardware.

What's thrown a wrench into the works is that shareholder Raging Capital Management believes a bigger deal could be out there. The hedge fund, which owns 6.7 percent of EZchip, believes Mellanox's bid is too small and claims EZchip has snubbed other potential buyers. EZchip says that isn't true.

Raging Capital also tried to get two shareholders elected to EZchip's board. That vote took place today, and the Raging nominees were shot down.

EZchip shares closed trading up nearly 2 percent today, at $24.38.