EZchip uses a sole supplier model for its NP.
It is now solely engaged with TSMC 55nm for its NP-4 (ASIC developed by Marvell) which is now ramping in Cisco and Juniper.
Next-gen NP-5 will also be designed by Marvell with TSMC 28nm and will sample by Q1 2013.
However, with Marvell buying EZchip competitor Xelerated in Q1 2012, EZchip will be forced to design its own ASIC for NP-6.
I think it will stick with TSMC.