MAP-T (was: Re: V6 still not supported)

Rajiv Asati (rajiva) rajiva at
Fri Mar 25 21:44:19 UTC 2022

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

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).



-----Original Message-----
From: NANOG < at> on behalf of Vasilenko Eduard via NANOG <nanog at>
Reply-To: Vasilenko Eduard <vasilenko.eduard at>
Date: Friday, March 25, 2022 at 11:17 AM
To: Jared Brown <nanog-isp at>, "nanog at" <nanog at>
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).

    -----Original Message-----
    From: NANOG [ at] On Behalf Of Jared Brown
    Sent: Friday, March 25, 2022 4:49 PM
    To: nanog at
    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

    - Jared

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