[Bloat] Bloat goes away, but with ~25% speed loss?

[Kevin Darbyshire-Bryant]

On 05/06/2015 21:06, Dave Taht wrote:
> 63% F bloat grade for
> http://www.dslreports.com/speedtest/results/isp/r3895-Orange%20Broadband
>
> I was disappointed to see the numbers for free, but wish I had insight
> into up vs down for their bloat scores.
>
> http://www.dslreports.com/speedtest/results/isp/r2816-Free%20France
>
> but... so wonderful to sit on a vantage point across the world! Way to
> go justin!
Hi Dave,

I'd like to urge caution about using 'whole ISP' bufferbloat figures.
 In the UK there are quite a few aspects that are quite simply out of an
ISP's control.  If I were an ISP I'd get rather annoyed by the 'ISP
ranked by speed results' sites out there, adding bufferbloat, certainly
without up/down split out is adding insult to injury.  This is going to
be a long post so feel free to skip/delete :-)

In the UK for example the delivery technologies are cable (1 supplier,
Virgin Media), adsl (many suppliers), vdsl (1 supplier, BT)  Virgin have
most control over CPE kit.  ADSL is a free for all.  VDSL2 was down to 2
modems (Huawei & ECI) but this is expanding outward toward free for all
status.

ADSL cpe is mostly 1 box combined modem/router often supplied by ISP. 
VDSL is mostly so far a 2 box solution with 100mbit ethernet twixt
modem/router.  Heading more towards 1 box solution (modem/router/wifi)

In cabled areas Virgin control network.  Each region/cabinet has own
level of contention/congestion.  Where not cabled area they use adsl
solution provided by BT.

ADSL on exchange by exchange basis may have BT only presence or 'a.n.
other suppliers' presence, known as LLU eg Talk Talk, Sky etc.  If
supplier has no local presence then offers service via BT kit.

VDSL at present is BT Openreach only kit in near-to-home cabinets.  BTO
trunk all data back to the exchange and then (I assume) it's split out
across the various ISP backhaul vlans.

Backhaul links between exchanges to ISP POPs may be provisioned by own
supplier (eg Sky, TalkTalk) or BT, all at differing bandwidths etc.

Some ISPs are much better at monitoring lines, latency, usage etc both
CPE and backhaul.  A&A are excellent at doing this, not only do they
have the tools, they actually use them!  They frequently identify
latency increases (and in extremis packet drops) on backhaul links from
their suppliers (mostly BT)

A&A are a good example here: A&A are the ISP but they use BT backhaul
and BT Adsl kit to supply service all over the country.  They monitor
links and provision (ie purchase) bandwidth from BT with the aim of not
being the bottleneck for their customers.  A.N.Other ISP may provide
service in exactly the same way, using the same BT kit but not purchase
sufficient bandwidth.  For the sake of completeness, A&A in 'TalkTalk'
enabled exchanges can also use 'TalkTalk' backhaul

Aside from any ISP backhaul issues or not, 'speed' is fundamentally
limited by 'the last mile' of copper, changing ISP doesn't change that
last mile unless changing technologies (ADSL->Cable->VDSL)  There's a
fundamental lack of understanding in this country as to how 'broadband'
actually works and I get dismayed by the many conversations I hear that
go something like "You should use ISP A, they're great, ISP B are crap. 
Oh but I use ISP B and they're great and ISP A are crap".  This is aside
from 'what do you mean by crap?', slow all the time?, slow when
up/downloading? (ahh, bufferbloat!)  (note to self:  You really should
finish your blog post on this topic Kevin!

BT for all their faults, do run rate limiters on the 'downlink' side so
as to not (hopefully) overfill the pipe from ISP to customer (A&A have a
means whereby they rate limit before BT if desired) so I'd like to think
that 'downlink' bufferbloat should be reasonably controlled in this
country.  Where it all turns to rat shit is on the uplink, many, many
different types of CPE, little under ISP control/specification (3rd
party adsl router/modems available freely in stores)  Add routers
running 3rd party firmware to the mix (OpenWrt, Tomato, Merlin's AsusWrt)

I guess I'm concerned that another means of beating ISPs is being
developed where the signal to noise ratio is actually very low and
sensible interpretation needs to be applied.  If going anywhere near
this I think showing up & down bloat ratings mandatory.

In the interests of full disclosure I'm not actually an A&A customer
(though I was a few years ago)  They're an excellent ISP with superb
customer service and clue.  They are probably more expensive than I
wished to pay for...customer service and clue isn't cheap.  Whilst my
current supplier (Sky...VDSL2 so actually BTO) is good and so far
reasonably reliable I *instantly* lose the will to live and want to
slash my wrists when speaking to their customer service.  I do keep
looking at A&A muttering 'native IPv6, unfiltered, customer service with
clue' though.  Breaking away from the 'triple play' service from Sky
with the associated discounts and benefits is going to be hard.  Clue
isn't cheap.

I've rambled enough.  There's some fun to be had reading Adrian's
battles with his favourite telco, example here:
http://www.revk.uk/2015/02/congestion-case-study.html

-- 
Cheers,

Kevin at Darbyshire-Bryant.me.uk <mailto:Kevin at Darbyshire-Bryant.me.uk>

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