Re: [v6ops] draft-smith-v6ops-larger-ipv6-loopback-prefix-04

[Gyan Mishra <[e-mail]>]

On Mon, Nov 2, 2020 at 1:35 AM Fred Baker <[e-mail]> wrote:

>
>
> > On Oct 29, 2020, at 1:42 AM, Mark Smith <[e-mail]> wrote:
> >
> > I've thought that the use of Anycast would increase, and have thought
> that it would be useful to have a specially designated anycast prefix. It
> has also occurred to me that anycast has some of the properties of unicast
> as well as some of the properties of multicast, so could be seen to fit in
> between unicast and multicast (1:1 -> 1:Any -> 1:Many)
>
> That's a reasonable description of anycast as deployed.


   Gyan> Agreed

>
>
> My question in that would be exactly what you might want to change. We
> have some pretty widespread use of anycast today (
> https://www.iana.org/domains/root/servers https://root-servers.org), and
> to my knowledge it seems to work just fine. If we're going to replace
> existing anycast with some sort of anycast prefix, the first big change we
> have to make is in BGP; it can advertise a unicast prefix or address, but
> can't, today at least, advertise an anycast prefix.Then we have to tell
> hosts that they can send traffic to such addresses and should. I think we
> should have a good reason if we're going to boil the ocean.


   Gyan> Good point and as you mention services such as DNS, NTP
predominantly but even Syslog, snmp, netflow have gone the way of Anycast
VIP advertisement via a lb for proximity routing to unicast address for a
just about any service can be done the ASM way and works very well.

I think with IPv6 a lot of thought was put into the addressing schema I am
guessing like the built in Anycast range out of the GUI range without a use
case but hopes for if you build they will come which I guess never
happened.  So then I guess it never took of as it would require some
changes to BGP.  Working with BGP on parameters and codepoint development
in some of the other WGs, if there is a real gain or use case for an
Anycast BGP SAFI  I could author a draft to make it happen but I would need
to figure out the why and what gap is not being filled by the existing
Anycast capability via unicast today which has been widely  proliferated.

> --

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*Gyan Mishra*

*Network Solutions A**rchitect *



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