The only basis I have for this is that "I keep hearing it" and sometimes the rumors that keep coming back are the ones that are true: but what I keep hearing is that a lot of what CA does internally for customer-facing roles (support, customer service, services, etc), Broadcom traditionally outsources to a service provider like HCL, Wipro, etc.
That is in the hardware world though - it's a very different world because Broadcom's customers are not the end-users of the products; they are manufacturers who are themselves selling to end-users. In software, Broadcom will be selling to, supporting, and servicing end-users, so it's possible they will take a different approach.
My best "educated guess", having worked in the field of Support for many companies over many years, is that SME's will be retained on transition to train their replacements in lower cost locations. Most of the US and Western Europe support will be sent to Asia and Eastern Europe over time. I give it 6-12 months depending on the complexity of your product.