From: "Jason A. Donenfeld" <Jason@zx2c4.com>
To: George Walker <georgewalkeriv@gmail.com>
Cc: "Toke Høiland-Jørgensen" <toke@toke.dk>,
"Juliusz Chroboczek" <jch@irif.fr>,
"WireGuard mailing list" <wireguard@lists.zx2c4.com>,
"Dave Täht" <dave@taht.net>
Subject: Re: [RFC] Multicast and IPv6 Link Local Addresses
Date: Fri, 7 Apr 2017 22:42:22 +0200 [thread overview]
Message-ID: <CAHmME9oxt=x3tJ5wHitGGjD1yLGweQ4ed3aNv+0Cv9bvPUXDDg@mail.gmail.com> (raw)
In-Reply-To: <03B23E99-75C4-4598-AC0A-3C65F346675F@gmail.com>
Hey George,
More excellent feedback, thanks. Be sure to CC the list next time though.
If I understand correctly, your suggestion is to not clutter
everything with a horrible "multi:" prefix, but instead allow
multicast addressees, which are well defined, to be added to multiple
peers, and only allow unicast addresses to be added to one peer at a
time keeping the current behavior. I find that a very nice UI
solution. Wonderful.
Jason
On Fri, Apr 7, 2017 at 6:02 PM, George Walker <georgewalkeriv@gmail.com> wrote:
> Cons:
> - A bit too magical.
> - Seems to break paradigm.
>
>
> Another is scalability --the computational and network overhead associated
> with making every peer irrevocably a member of every multicast group.
> Sending all multicast messages to all peers eliminates much of the benefit
> of having more than one multicast address. That could mean a lot of
> unnecessary handshakes! I can imagine applications for which this behavior
> would make (accidental or malicious) DoS very easy.
>
> If you only have a lab-scale deployment and generous bandwidth, of course
> receive-side filtering is fine. But Wireguard's performance and general
> utility would suggest that some will want big far-flung networks that may
> well have need for lots of multicast groups (e.g. industrial IoT), while not
> being able to afford to broadcast everything to everyone.
>
> Thus, there'd have to be
> some explicit way of telling it, "yes I really do want this to be
> duplicated, not moved". Perhaps a "multi:" prefix?
>
>
> I respectfully disagree concerning the necessity to add special, ugly,
> inconsistent UI for the multicast-as-multicast (instead of
> multicast-as-broadcast) approach. Multicast address ranges are well-known,
> specified in RFCs. That they behave a little bit differently from unicast
> addresses is expected behavior. Most of us ignore them and don't use those
> ranges most or all of the time, which works fine. Thus Multicast support
> (e.g. in routers) doesn't generally interfere with the actual vs. expected
> behavior of the unicast traffic most people use most of the time.
>
> Anyone who is diddling with networking at this level already knows how to
> avoid multicast IPs when they intend unicast (whether they know they do or
> not).
>
> It doesn't seem problematic for a layer 3 VPN to treat adding a unicast
> address when such an address is already an allowedIP as different from
> adding a multicast address (moving in the first case, adding in the second).
> It sounds to me like doing the right (intuitive) thing in each case.
next prev parent reply other threads:[~2017-04-07 20:35 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-07 14:02 Jason A. Donenfeld
2017-04-07 14:31 ` Jason A. Donenfeld
[not found] ` <03B23E99-75C4-4598-AC0A-3C65F346675F@gmail.com>
2017-04-07 20:42 ` Jason A. Donenfeld [this message]
2017-04-08 12:43 ` Toke Høiland-Jørgensen
2017-04-08 15:44 ` George Walker
2017-04-08 9:39 ` Dan Lüdtke
2017-04-08 17:15 ` Juliusz Chroboczek
2017-04-08 19:05 ` Juliusz Chroboczek
2017-04-17 14:11 ` Baptiste Jonglez
2017-04-17 16:55 ` Toke Høiland-Jørgensen
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