I’m curious about something so I’m going to throw this thought experiment out here. For some background I run a pure IPv6 network and dove into v6 ignoring any v4 baggage so this is more of a devils advocate question than anything I genuinely believe.

Onto the question, why should I run a /64 subnet and waste all those addresses as opposed to running a /96 or even a /112?

  1. It breaks SLAAC and Android

let’s assume I don’t care for whatever reason and I’m content with DHCP, maybe android actually supports DHCP in this alternate universe

  1. It breaks RFC3306 aka Unicast-prefix-based multicast groups

No applications I care about are impacted by this breakage

  1. It violates the purity of the spec

I don’t care

What advantages does running a /64 provide over smaller subnets? Especially subnets like a /96 where address count still far exceeds usage so filling subnets remains impossible.

  • ScooptaOPEnglish
    2·
    1 year ago

    Even if that’s the case it doesn’t really change anything. I was more asking from an end user perspective as I’m hoping we never end up at a point where providers start doing this, however even if they do it doesn’t actually change anything in their routing table. Let’s say providers start giving everyone a /80 instead of a larger block, if they have 50 customers, 50 /80s is no worse than 50 /56s. The only time deaggregation is a problem is when the total number of routes increases but that’s not going to be caused by this as the point of the argument is if you don’t use /64s everywhere than almost any sized block becomes big enough for any sized organization. I really don’t understand why some people hate using a /64 everywhere, it’s not wasteful, it’s the design goal but that’s why this post exists to try to understand the technical downsides and unfortunately so far I’m wishing there were more than Android stops working and your network looks uglier.

    • MSgtRedFox@infosec.pubEnglish
      1·
      1 year ago

      Yeah I don’t get it either.

      I take more issue with how v6 is going to work with SMB, hint the other post. I am hoping when my ISP stops denying the existence of v6, maybe they’ll do reasonable allocation or PD.

      • ScooptaOPEnglish
        2·
        1 year ago

        All ISPs should do PD unless you’ve got some very special setup and they give you something that must be manually configured. Honestly too many ISPs still lack IPv6 and it’s baffling. I have a friend with Verizon FiOS and after years of not having it he finally got it earlier this year I think…only to have it get taken away a little while ago. Like what?