Custom private addressing (CPA) is a SoftLayer feature that lets the customer choose the private IP address range used by their servers. The customer may define up to 5 CPA Networks using any RFC 1918-valid IP address range (10.x.x.x, 192.168.x.x, 172.16.x.x). Customer-defined subnets split each CPA Network into smaller address ranges, with each subnet associated with a location—a data center and Pod—in SoftLayer’s global private network.
All private subnets within a given CPA Network are routed together, creating a flat, globally-routed private address space. Private IPs are not routed across CPA Networks, making each Network a segregated private routing domain.