A Farewell to ARPs: IPv4 Service on IPv6-Only Networks

55 pointsposted 2 days ago
by speckx

8 Comments

throw0101d

2 days ago

ARP is not an issue at smaller scales, but at larger ones it can cause problems. Reducing the L2 broadcast 'blast radius' is one of the touted benefits of EVPN (which use may be worth considering once you get above ~20 switches):

* https://www.youtube.com/watch?v=W_z37Rq7qgY

inigyou

2 days ago

Saw this in IETF already but it's not clear why it's useful especially as the old path still needs to be implemented for compatibility. TFA is obviously LLMslop, which is very disappointing from RIPE.

throw0101d

a day ago

For corporate networks, where you control what devices get onto non-guest VLANs/subnets, you'll have better control over devices that support this new functionality. See for example Google's work on removing IPv4 on corporate networks:

* https://www.youtube.com/watch?v=UTRsi6mbAWM

Even in organizations where IT cannot control devices, like universities which are largely student-BYOD, IPv6 take-up can reach 80%:

* https://www.youtube.com/watch?v=2B-liebzcOMmkm&t=10m

"Obviously" in what way?

inigyou

a day ago

But why is this little hack advantageous over dual-stack? Advanced switches already don't forward ARPs they can handle locally.

throw0101d

a day ago

Because dual-stack means having to deal with stand up IPv4, which entails more configuration, more address planning, more infra, etc. See perhaps "§5.1 IPv6-only Compared to Dual-Stack":

* https://datatracker.ietf.org/doc/html/draft-ietf-v6ops-6mops

Fewer IPv4 deployed subnets means those addresses can be used where they're 'really' needed instead of being 'wasted'.

_bernd

a day ago

I don't get your question? If you use a /32 then there is no broadcast address and no ARP. And the /32 are then announced by your internal routing protocol.

alhidade

2 days ago

> That's real, but it understates the problem.

It's all so tiresome.

illliillll

a day ago

What drives people to post blatant slop like this?