[Cerowrt-devel] [Bloat] [aqm] the side effects of 330ms lag in the real world
jg at freedesktop.org
Tue Apr 29 12:57:31 EDT 2014
On Tue, Apr 29, 2014 at 12:44 PM, Jim Gettys <jg at freedesktop.org> wrote:
> On Tue, Apr 29, 2014 at 3:56 AM, Mikael Abrahamsson <swmike at swm.pp.se>wrote:
>> On Tue, 29 Apr 2014, Fred Baker (fred) wrote:
>> Well, we could discuss international communications. I happen to be at
>>> Infocom in Toronto, VPN’d into Cisco San Jose, and did a ping to you:
>> Yes, but as soon as you hit the long distance network the latency is the
>> same regardless of access method. So while I agree that understanding the
>> effect of latency is important, it's no longer a meaningful way of selling
>> fiber access. If your last-mile is fiber instead of ADSL2+ won't improve
>> your long distance latency.
> FIOS bufferbloat is a problem too.
> Measured bufferbloat, symmetric 25/25 service in New Jersey at my inlaw's
> house is 200ms (on the ethernet port of the Actiontec router provided by
> Verizon). So latency under load is the usual problem.
> Why would you think the GPON guys are any better in principle than cable
> or DSL? Cable and DSL may be somewhat worse, just because it is older and
> downward compatibility means that new modems on low bandwidth tiers are
> even more grossly over buffered.
> You can look at the netalyzr scatter plots in
Oh, I forgot to note: Netalyzr topped out at about 20Mbps: most of why
GPON looks good on those plots is just that the common lowest tier of
service (at the time that data was taken) it can't easily detect the bloat.
But if you perform other tests that don't have a bandwidth limit, the bloat
This reminds me I should ask Nick Weaver if he has more recent data...
Now, if someone gives me real fiber to the home, with a real switch fabric
> upstream, rather than gpon life might be somewhat better (if the switches
> aren't themselves overbuffered.... But so far, it isn't.
> - Jim
>> Mikael Abrahamsson email: swmike at swm.pp.se
>> Bloat mailing list
>> Bloat at lists.bufferbloat.net
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