TFTP over anycast

Sat Feb 24 06:36:20 UTC 2024

> On Feb 23, 2024, at 20:32, William Herrin <bill at 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.

Ask
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.nanog.org/pipermail/nanog/attachments/20240223/634b6da9/attachment.html>