FWIW, MAP has been deployed by few operators (in at least 3 continents that I am aware of). Charter communications is one of the public references (see NANOG preso https://www.youtube.com/watch?v=ZmfYHCpfr_w). MAP (CPE function) has been supported in OpenWRT software (as well as many CPE vendor implementations) for few years now; MAP (BR function) has been supported by few vendors including Cisco (in IOS-XE and XR). Cheers, Rajiv https://openwrt.org/packages/pkgdata_owrt18_6/map-t https://openwrt.org/docs/guide-user/network/map -----Original Message----- From: NANOG <nanog-bounces+rajiva=cisco.com@nanog.org> on behalf of Vasilenko Eduard via NANOG <nanog@nanog.org> Reply-To: Vasilenko Eduard <vasilenko.eduard@huawei.com> Date: Friday, March 25, 2022 at 11:17 AM To: Jared Brown <nanog-isp@mail.com>, "nanog@nanog.org" <nanog@nanog.org> Subject: RE: MAP-T (was: Re: V6 still not supported) Hi Jared, Theoretically, MAP is better. But 1. Nobody has implemented it for the router. The code for the CGNAT engine gives the same cost/performance. No promised advantage from potentially stateless protocol. 2.MAP needs much bigger address space (not everybody has) because: a) powered-off subscribers consume their blocks anyway b) it is not possible to add "on the fly" additional 64 ports to the particular subscriber that abuse some Apple application (and go to 1k ports consumption) that may drive far above any reasonable limit of ports per subs. Design should block a big enough number of UDP/TCP ports for every subs (even most silent/conservative). Ed/ -----Original Message----- From: NANOG [mailto:nanog-bounces+vasilenko.eduard=huawei.com@nanog.org] On Behalf Of Jared Brown Sent: Friday, March 25, 2022 4:49 PM To: nanog@nanog.org Subject: MAP-T (was: Re: V6 still not supported) Most IPv6 transition mechanisms involve some form of (CG)NAT. After watching a NANOG presentation on MAP-T, I have a question regarding this. Why isn't MAP-T more prevalent, given that it is (almost) stateless on the provider side? Is it CPE support, the headache of moving state to the CPE, vendor support, or something else? NANOG 2017 Mapping of Address and Port using Translation MAP T: Deployment at Charter Communications https://www.youtube.com/watch?v=ZmfYHCpfr_w - Jared