There was a time when the term "virtual customer premises equipment (vCPE)" was kind of ambiguous. But as network functions virtualization (NFV) starts to shake out, the term has become more clear.

IDC recently published a report that covers the worldwide market for NFV infrastructure at the network edge. And IDC says vCPE is the term for software at the edge, while universal CPE (uCPE) refers to the hardware at the edge. And “the edge” for purposes of IDC’s report could be: 1) on premise at the enterprise branch; 2) at the service provider point of presence; or 3) at the service provider data center.

In the report “Worldwide vCPE/uCPE Forecast, 2017–2021: NFV at the Network Edge,” IDC estimates that the worldwide vCPE/uCPE market – hardware and software – will exceed $3 billion by 2021. It forecasts the vCPE software market to grow from $145.7 million in 2016 to $2 billion in 2021 at a compound annual growth rate (CAGR) of 68.3 percent. The uCPE hardware market is expected to grow from a base of $67.8 million in 2016 to $1.16 billion in 2021 at a CAGR of 76.4 percent.

Some of the functions of vCPE, according to IDC, include software-defined wide area network (SD-WAN) routing, security, WAN optimization, and session border control. Virtual network functions (VNFs) are delivered on multi-tenant commodity infrastructure, uCPE, instead of several proprietary physical appliances at the network edge.

Regarding hardware, IDC said that uCPE could reside on “commodity hardware.” But there are other terms that are still shaking out in the NFV ecosystem, including “white box.”

Recently, AT&T’s Chris Rice talked about the Open Architecture for a Disaggregated Network Operating System (dNOS), which is the operator’s network OS for white box.

Asked what he meant by “white box,” Rice said, “It’s really something that doesn’t use standard CPU for the data plane. It’s using some kind of network processor for the data plane.”

He said a CPU from companies such as Intel or AMD are generalized processors meant to do many tasks pretty well. Whereas a network processor from companies such as Barefoot, Broadcom, or Cavium does a few things really well. “Network processors route packets at a very high rate; that’s the routing data plane I’m talking about,” said Rice. “As opposed to things you can do at a CPU in the cloud.”