Re: TFTP over anycast

[Ask Bjørn Hansen <ask () develooper com>]

> On Feb 23, 2024, at 20:32, William Herrin <bill () herrin us> wrote:
>
> > The relay server `dhcplb` could, maybe, help in that scenario
> > (dhcplb runs on the anycast IP, the “real” DHCP servers on
> > unicast IPs behind dhcplb).
>
> Although they used the word "anycast", they're just load balancing.

The idea is to run the relays on an anycasted IP (so the load balancer / relay IP is anycasted).

> [….] Relying on ECMP for anycasted DHCP would be a disaster
> during any sort of failure. Add or remove a single route from an ECMP
> set and the hashed path selection changes for most of the connections.


Consistent hashing (which I thought was widely supported now in ECMP implementations) and a bit of automation in how 
announcements are added can greatly mitigate this.



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