el of disaggregation based on platform volumes and total cost of ownership (TCO) analysis. There are two emerging graybox models. Model 1, which became commonplace in 2015, is where the platform is purchased from a third-party integrator that pro- vides an ODM merchant silicon whitebox plus software plus support and maintenance for a fee above and beyond the ODM whitebox purchase price. Model 2, which gained some momentum in 2016, where an OEM sells the platform without a NOS but with a simple bootstrap loader such as open network install environment (ONIE) or preboot execution environment (PXE). In this model, the OEM still supports lifecycle management of the hardware but the NOS is disaggregated. 12.4.3 EDGE vPE VNF The virtual provider edge (vPE) VNF software that runs on standard cloud hardware is the second major component in the disaggregated packet edge platform. The purpose of this VNF is to provide the packet edge processing functions for all the various edge applications described in Section 12.3.2. These functions cannot typically be done by merchant silicon because of their reduced functionality support. One starting requirement in new installations of disaggregated routers is that the packet service specification be at parity and fully interoperate with preexisting vertical routers in production. This is for the simple reason that for a new technology to be successful it must be easily adopted by the end customer and their existing networks. Once it is adopted at par, then it becomes easy to evolve the service with new value-added capabilities. As noted earlier, merchant silicon traded reduced functionality to significantly lower cost and to increase throughput when compared to custom Network Edge silicon on traditional routers. These functional gaps mean that merchant silicon platforms cannot replace traditional routers. To fill these gaps, we turn to VNF software. There are many evolving architectures for vPE software. vPE software, in general, can be disag- gregated into five major modules (Figur