Re: IPv6 Performance (was Re: IPv4 Pricing)

[Tom Beecher via NANOG <nanog () lists nanog org>]

> At least once or twice a month I'm downloading something and will find the
> IPv4 to transfer significantly faster.  Case in point, I downloaded the
> proxmox iso yesterday to a colo server with 50g uplinks.  It loafed at 2.4
> mbytes/s using default wget, which of course preferred ipv6.  Adding -4 to
> wget made that shoot up to 80 mbytes/s.


Lots of reasons that could explain that which have nothing to do with
traffic being v4 vs v6.

On Mon, Dec 1, 2025 at 4:44 PM Bryan Fields via NANOG <nanog () lists nanog org>
wrote:

> On 12/1/25 14:22, Jared Mauch via NANOG wrote:
>
> > I find myself having to tether off their networks when I’m on IPv4 only
> > networks to access things like my hypervisors and other assets that are
> > IPv6-only because they have superior networking these days.
>
> While I'll agree v6 is easy and should be deployed I have to take issue
> with
> the current as-built being superior.
>
> At least once or twice a month I'm downloading something and will find the
> IPv4 to transfer significantly faster.  Case in point, I downloaded the
> proxmox iso yesterday to a colo server with 50g uplinks.  It loafed at 2.4
> mbytes/s using default wget, which of course preferred ipv6.  Adding -4 to
> wget made that shoot up to 80 mbytes/s.
>
> This is ipv6 behavior I've seen time and time again.  I'm unsure where
> problems like these lie in the network, other than it's not mine or my
> peers.
> I've seen the same issues with v6 paths to the same server bounce around
> the
> west coast and back, whilst IPv4 is 6 hops and 12 ms away.
>
> This is exactly the sort of thing that holds IPv6 back by giving it a bad
> name.
> --
> Bryan Fields
>
> 727-409-1194 - Voice
> http://bryanfields.net
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>
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