A "white-label switch" that is really just a reseller layer on someone else's infrastructure has a ceiling. Here is what a real one looks like.
A lot of "white-label softswitch" offerings are actually a reseller layer bolted onto someone else's infrastructure with your logo on top. That works until you need something the underlying provider was not built to give you.
6X Softswitch is the same routing engine 6X's own traffic runs on, not a reseller layer — your own dedicated IP, your own vendor relationships, flat monthly rent, hosted centrally or self-hosted on your own server for less.
See pricing: softswitch.6xcom.com.
Ask what happens if you want to add your own vendor relationship that the platform itself doesn't already have. A genuine white-label softswitch lets you plug in your own carrier and route your own traffic through it, isolated from other partners. A reseller layer with your logo on it usually can't — you're stuck with whatever carriers the underlying platform already chose, regardless of what better rate or relationship you might have found yourself.