What is Shared Address Space address range?

Question

What is IP address range block that can be used for Shared Address space range?

Answer 1

According to RFC 6598:

   The Shared Address Space address range is 100.64.0.0/10.

It can be used to accommodate the needs of Carrier-Grade NAT (CGN) devices.  It is anticipated that Service Providers will use this Shared Address Space to number the interfaces that connect CGN devices to Customer Premises Equipment (CPE) (RFC 6598)