In the current Internet, it is fairly common for ISPs to provision their subscribers with a single public IPv4 address and for those subscribers to use NAT technology to allow multiple machines in their networks to access the Internet. This setup essentially requires one public IPv4 address per subscriber. As the IPv4 free address pool becomes depleted, it seems likely that ISPs will not have enough public IPv4 addresses to assign one address per subscriber. When that happens, multiple subscriber networks will have to share a single public IPv4 address. Multiple approaches have been proposed in order to implement the sharing of public IPv4 addresses, as described in section 2.1 of draft-arkko-townsley-coexistence-00. The goal of this BOF is to discuss and gain understanding of a particular family of solutions, the so called distributed-NAT approaches described in section 2.1.2 of draft-arkko-townsley-coexistence-00. This family of solutions, essentially assigns a public IP address and a port range to each subscriber and relies on some form of port range routing capability within the ISP network. The result is that each subscriber still obtains at least a part of a public IP address and retains some of the capabilities of the current configuration. During the BOF we intend to discuss the following items: - Problem characterization: We need to understand what is exactly the problem, what are the different scenarios that are affected by the IPv4 address space depletion and what are the possible approaches to address the problem. In addition, we need to identify the different relevant aspects of the problem and solution space that need to be taken into account during the discussion of the solution space. - Motivation for SHARA: Discuss the benefits and potential issues with a distributed NAT approach. - Distributed NAT approaches: Explore the solution space for distributed NATs and the implications of the relevant aspects previously identified. - Interaction with other efforts. There are a significant number of efforts in related areas, such as the work being done in the BEHAVE WG and the SOFTWIRES WG. It is then relevant to understand how the proposed mechanisms interact with these. - Implication for the deployment of IPv6. Any mechanism that aims to extend the lifetime of IPv4 can potentially delay IPv6 deployment. An analysis of the impact of the adoption of these techniques is needed. This is non-wg forming BOF and the goal is to provide input material to the community in general and the IESG in particular for them to scope out what gaps still need to be addressed in chartered WG items in other WGs.