Realistic number of hosts for a /64 subnet?
swmike at swm.pp.se
Fri May 10 08:43:29 CEST 2019
On Thu, 9 May 2019, 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
It's a good topic to bring up. There has been some work on this in the
IETF, for instance https://tools.ietf.org/html/rfc8273
This means there is single broadcast domain and single /64 per customer,
which if properly implemented helps with a lot of the problem space people
like to solve in this area. It however includes moving away from quite a
lot of what you call "IPv4 thinking".
I however do not operate wifi networks so I have no idea how widely this
is implemented in gear available today. If someone else knows, I would
appreciate if they would share.
Mikael Abrahamsson email: swmike at swm.pp.se
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