1. OverviewΒΆ

One approach to cope with the public IPv4 address exhaustion is to share the remaining or available IPv4 addresses among a larger number of customers. It can be done by using CG-NAT.

CG-NAT, also known as Large Scale NAT, is a highly scalable NAT placed in the ISP core network, between the customer premises equipment (CPE) and the Internet.

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In NAT44(4), there are three IPv4 networks:

  • A private IPv4 network within the user network (behind the CPE),

  • A different private IPv4 network for the user to provider links (between the CPE and the vRouter), known as the Shared address space,

  • A public IPv4 network on the outside of the vRouter.