Realistic number of hosts for a /64 subnet?

Mark Tinka mark.tinka at
Fri May 10 08:26:46 CEST 2019

On 10/May/19 06:27, Doug Barton wrote:
> It's been a while since I was configuring subnets, and last time I did
> the guidance was always no more than 1,000 hosts per subnet/vlan. A
> lot of that was IPv4 thinking regarding broadcast domains, but
> generally speaking we kept to it for dual stacked networks, equating
> an IPv4 /22 with an IPv6 /64. (This was commonly in office
> environments where we used a subnet per floor to accommodate all of
> the desktops, printers, phones, tablets, etc.)
> Is this still how people roll nowadays? Have switches and/or other
> network gear advanced to the point where subnets larger than 1k hosts
> are workable? In IPv4 or IPv6? I've done quite a bit of web searching,
> and can't find anything newer than 2014 that has any kind of
> intelligent discussion of this topic.

Well, WLAN environments comes to mind. It is possible to find three or
more thousand devices on a single (V)LAN, be it IPv4 or IPv6. Think
large conferences, a stadium, a concert, e.t.c.

Whether a single LAN can scale to the number of devices a /64 can
maximally support... I don't think so, but I also don't know of anyone
who has tried.


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