[Babel-users] tunnels

[Dave Taht]

On Sat, Oct 13, 2018 at 9:26 AM Justin Kilpatrick <justin at altheamesh.com> wrote:
>
>
> > > On Sat, Oct 13, 2018 at 12:01:54AM -0700, Dave Taht wrote:
> > I get that bandwidth figure a lot for wireguard. I care about  latency
> > far, far more under a full bidirectional load. Having got base wifi so
> > much better, and the edge connections sqm-scripts massively better, I
> > am wondering if wireguard got on the stick yet?
> >
> > I wrote about this problem in an early version of wireguard here:
> > http://blog.cerowrt.org/post/wireguard/
> >
> > As of kernel 4.4 (?) ipsec does take advantage of the fq_codel hash.
> > the before latency was 100+ms in the tunnel for voip, 2ms after.
>
> I can confirm that fq_codel works with Wireguard tunnels just fine. The latency added by a tunneled hop is around 1-2ms.

that is not a possible result. The classic simplest bufferbloat test
is start a ping, then do a big 60 sec upload or download from a server
on the other side of that link. Over wifi that's a minimum resulting
delay of 10ms, closer to 20, nowadays. about 2 over cake on ethernet.

but: Over the wireguard tunnel I tested 2 years or so back, 150ms induced delay.

from tcp on an openwrt router, it's probable that the pacing_rate bug
still exists which means it's tcp can't flood the link - which is a
good thing in this case but... users aren't on the routers. users
don't just ping or download or upload once at a time.

> Here's some iperf data, but not as latency focused as you would probably like.

nope. also udp fragmenting is iperf's default mode.

> https://forum.altheamesh.com/t/althea-performance/44/3
>
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-- 

Dave Täht
CTO, TekLibre, LLC
http://www.teklibre.com
Tel: 1-831-205-9740