Re: [Int-area] Main change in draft-ietf-intarea-provisioning-domains-03: connection sharing

[Alexandre Petrescu <[e-mail]>]

Le 24/10/2018 à 11:51, Eric Vyncke (evyncke) a écrit :
> The authors of this draft would like to have some discussions even 
> before the INTAREA WG meeting in two weeks. Especially on the major 
> change about connection sharing (tethering) where the authors spent 
> several hours on it.
> 
> See all differences in: 
> https://tools.ietf.org/rfcdiff?url2=draft-ietf-intarea-provisioning-domains-03.txt
> 
> The section 3.4.3 is about “Connection Sharing by the Host” and 
> currently is:
> 
> ------- start --------
> 
>     The situation when a host shares connectivity from an upstream
> 
>     interface (e.g. cellular) to a downstream interface (e.g.  WiFi) is
> 
>     known as 'tethering'.  Techniques such as ND-proxy [RFC4389 
> <https://tools.ietf.org/html/rfc4389>], 64share
> 
>     [RFC7278 <https://tools.ietf.org/html/rfc7278>] or prefix delegation 
> (e.g. using DHCPv6-PD [RFC3633 <https://tools.ietf.org/html/rfc3633>]) may
> 
>     be used for that purpose.
> 
>     Whenever the RAs received from the upstream interface contain a PVD
> 
>     RA option, hosts that are sharing connectivity SHOULD include a PVD
> 
>     Option within the RAs sent downstream with:
> 
>        The same PVD-ID FQDN.
> 
>        The same H-bit, Delay and Sequence Number values.
> 
>        The L bit set whenever the host is sharing IPv4 connectivity

I am not sure it is possible to 'share' IPv4 connectivity, in the same 
manner like sharing IPv6 connectivity.

There are no PVDs in IPv4, the 'sharing' is with NAT/DHCP, etc.

To achieve the same effect in IPv4 as in IPv6 (propagate info from 
upstream RA to downstream RA) one may need to specify:

- set in DHCP Advertise sent downstream the same DNS server as received
   in the DHCP Advertise from upstream.

Or maybe I dont understand the meaning of the L bit.  And I have to read 
the draft.

Alex

> 
>        received from the same upstream interface.
> 
>        The bits from the Reserved field set to 0.
> 
>     The values of the R-bit, Router Advertisement message header and
> 
>     Options field depend on whether the connectivity should be shared
> 
>     only with PvD aware hosts or not (see Section 3.2 
> <https://tools.ietf.org/html/draft-ietf-intarea-provisioning-domains-03#section-3.2>).  
> In particular,
> 
>     all options received within the upstream PvD option and included in
> 
>     the downstream RA SHOULD be included in the downstream PvD option.
> 
> ---- end ----
> 
> Comments are welcome before, during and after the WG meeting
> 
> -éric for all authors
> 
> 
> 
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