[NCLUG] Re: DSL Throttling or General Congestion?

[DJ Eshelman]

Nothing like reviving a near-dead thread with a nice long wordy email...

John put this well, I think- DSL/Cable are 'oversold' networks, where 
they hope that not everyone will be wanting to be on at the same time, 
and usually they are very correct.
Generally speaking, it works well enough for most home users, but as the 
problem increases, I think we'll see more and more of 'fiber to the 
home' kinds of services.  I'm not a network expert by any means but 
because of some extreme issues with this on the business side of things, 
I've been doing a lot of research lately.

Bottom line:  A lot of people confuse speed capability (download/upload 
speed) with *latency* as the reason why things are 'slow'.

EVERY TIME I've had an issue with DSL or Cable, I can track it down to 
line latency of 200 ms or more.  That is usually caused by too many hops 
before the CO, QoS, line congestion and just plain outdated designs in 
the TCP/IP protocol itself.  So, not necessarily 'throttling' of the 
connection, but definitely has that effect.  Any throttling that will be 
done is more to prevent these issues from causing timeouts than to 
actually squash the speed itself.  Add to that the sheer number of 
compromises along the way for 'download speed' reasons and you get 
latency WAY beyond a leased line.
Want proof?  Next time you're having an issue with 'slowness', go to 
http://www.speakeasy.net/speedtest (flash required) and run the test.  
You'll probably find the line itself is running at normal speeds, but 
your ability to actually download much of anything is nuts.  Ping tests 
to tier one providers will usually confirm this latency exists, and 
you'll see some crazy fluctuations during peak times.
 
It's also why VPN connections are so difficult to use practically, but 
what I'm finding is that I can't always convince my clients to put in a 
leased circuit (a p2p T-1 from Fort Collins to Greeley, for example, 
typically has an 8ms latency whereas an internet-based DSL connection 
averages 70-180ms (cable was worse at 130-2000ms, testing both from a 
Level3 Internet T-1 line).  Add the overhead of either IPSec or PPTP for 
your VPN and you've got major latency issues.  And in my world- having 
to deal with Windows/CIFS for the majority of what my clients are doing- 
my problems are huge because CIFS is an extremely chatty protocol that 
goes over TCP/IP for most of it's work.

So now to why I'm even addressing this to the group:  I've been trying 
to find open source solutions to get around these latency issues 
(packeteers and such) and haven't had much luck.  Anyone else out there 
dealing with these issues/have any ideas?

Theoretically, the best things to do for a site-to-site network would be 
to have boxes on both ends such as the Citrix WANScaler or similar 
solution.  Amazing technology- it caches packet streams and sends CRC 
queries to the remote box to see if it's the same stream- if it is, it 
just repeats it locally, if not, the sending box translates it to UDP, 
compresses and sends the whole stream at once, then asks for 1 
confirmation of the entire stream/file instead of the hundreds of 
confirmations required by TCP/IP.  There's more features but that's the 
one I really like because it satisfies the 'chatty' protocols without 
letting them be 'chatty' across the line itself.

This is amazing and I'd really like to have a sub-$2,000 solution for my 
clients with branch offices.  Even the cheapest packeteer solution is 
/way/ more and the only open source projects I've found so far deal with 
compression (which doesn't address latency all that well), but little 
else.  As far as I know, the WANScaler has a x-nix type kernel (possibly 
BSD) so surely there's something out there!

Ironically, Citrix also sells interface software that lets you connect 
to a WANScaler from your PC and get the same benefits.  You'd think that 
the ISPs (especially Satellite) would be all over this.  So far the only 
software I've ever seen has just done site-to-site compression, but it 
would cut down so much on the chattyness of TCP/IP networks; but likely 
people would freak out that they'd be 'spying on me' or something.  
Personally, I think it'd be worth the risk.

Now for the rant about DSL vs Cable to the home, which can be completely 
ignored if you like- I just am ticked and need to vent...

<rant>

Personally, what sells me on DSL vs Cable is the service- and when I say 
service, I mean the people.

A few weeks ago I moved and asked Comcast to move my service, not 
thinking that I should have called Qwest to see if my new home qualified 
better than my old one (which only had 1.5 Mbit down max).
They asked me when I would like the install, and gave me a day about 10 
days into my being at the house.  The tech said between 10 and noon (but 
apparently scheduled 3-5 without me knowing it).
So, my roommate volunteered to meet the tech there at 10 and spent the 
entire day on the couch waiting for this guy.

After calling them at 1 to find out they'd changed the schedule on me, I 
told my roommate to be sharp at 3-5 that he'd be coming then.

I get home at 5:30 to find a tag on my door that the tech had been there 
and no one was there, so I'd have to reschedule.
Now, I have a LOUD doorbell- it'll rouse you from the dead.  There's no 
way that he rang it, and in fact probably didn't even knock.

Furious, I called Comcast to see what was going on.  The tech even 
claimed to have called me, and I had her read back my cell number.  No 
calls, no voice mail.  Recognizing that this was only one person and 
that this was a busy time, I asked to have clarification- at which point 
the person I was talking to basically told me that both my roommate and 
I had to be mistaken because her notes say he was there.
Game over.  This isn't the first time that I've dealt with this with 
Comcast but it will be the last.

So I called Qwest.  They got me a DSL package for less with better 
speed, and required nothing from me, even let me program the router 
myself instead of having to jump thru hoops.
So I suppose I have been one of those people that have 'jumped back and 
forth between cable and DSL'- but honestly I would have never left Qwest 
if I didn't live in an odd area last year.  Frankly, I know that paying 
less than $100 a month for 12Mbit down and 865Kbit up is great, I'm 
willing to put up with a lot for the actual electronic service- I just 
don't like being treated like I'm just lying to get better service or 
something by Comcast.
And as a side note- Qwest ended up being cheaper and I'm getting better 
practical speeds than Comcast.
Add to that my recent experience with FRII; I think that was a problem 
with a day when they had almost everyone gone, but I was on hold for 
well over an hour trying to get a DSL issue resolved, then the next day 
a half hour and a 'field tech' that attacked my credibility to the 
client; only to find out that it was just a problem in how FRII had 
programmed the line after trying three different DSL boxes, one that was 
known good from my own home.

Service is everything.  The client is leaving FRII because they had to 
pay for my time to deal with them and sit on hold.
Contrast that with my experiences with just going thru Qwest and I have 
to say that despite some personal grievances with Qwest's business 
practices- bottom line is that the service people I've dealt with have 
always been better and I've never felt degraded after a call with them.  
In fact, they're usually thrilled to have someone on the line who 
actually knows what PPPoE is.  Another client who had Qwest DSL at home 
had a router go bad- what would have been a 15-30 minute conversation 
with Comcast or even FRII was a 3 minute call.  "Red power light?  We'll 
send out another unit right away."  That's what it should be.

I feel better now :)

</rant>

-DJ

John L. Bass wrote:
> Jim Hutchinson wrote:
>> On Sun, Jul 27, 2008 at 11:52 AM, Ben West <mrgenixus at gmail.com> wrote:
>>
>>  
>>> the fact is, DSL is and always will be a shared-access medium, it 
>>> would be
>>> fraudulent for them to sell you a higher service level, considering 
>>> they
>>> can't currently provide you with your maximum allocation...  You're
>>> proposing to pay for a bigger buffet at a restaurant where they 
>>> can't keep
>>> all the food-stations full to begin with....  perhaps if you need more
>>> bandwidth, you should find out if they have any dedicated-access 
>>> options
>>> available?
>>>     
>>
>>
>> What do you mean by shared-access? My understanding is that cable is 
>> shared
>> and that if a lot of people in your area are online you will see a 
>> decrease
>> in performance. By contrast, DSL gives you a dedicated line to a point -
>> usually a junction box. The further to box the slower your connection 
>> can
>> be. As a result, you should not see changes in speed based on how many
>> people in your area are online. There may be other issues that affect 
>> speed
>> but my understanding was that it's not shared the same way as cable is.
>>
>>
>>   
> Your cable line to the pole is dedicated too, and shortly there after 
> ends up in a statistical multiplexor. Every .... repeat ... every 
> internet form does that at some level, including T1 lines.  For 
> example, when I was purchasing services from NCIC 10 years ago, they 
> had two T1 lines from Boulder and resold that bandwidth over 
> subscribed by a factor of about 10. Your ethernet, ISDN, or T1 
> connection to NCIC was dedicated, and ended up over subscribed at the 
> NCIC router.
>
> It really doesn't matter if your shoestring, or giant water main is 
> dedicated, if it necks down anywhere after leaving your place.
>
> At CWX we have always been open about how we over subscribe our 
> network hardware and costs to set service levels and rates. Few other 
> ISP's will be honest about their minimum engineering and cost over 
> subscription ratios. We are frequently more expensive than other 
> wireless solutions because of our low over subscription ratio, where 
> competitors put several times the number of customers on the same 
> resources. We do so at cost, which isn't always cheapest compared to 
> lower cost areas in the city where cable and CO based DSL services 
> rule. We freely tell our customers to take the best wired option they 
> can find, as it's likely to be faster, more reliable, and cheaper than 
> high ground wireless. We are faster, more reliable, and cheaper than 
> satelite, which is the only other option for many of our customers.
>
> The only place where you get dedicated internet bandwidth is 
> purchasing from a tier 1 or 2 provider with an SLA that specifically 
> says you have that bandwidth guarenteed 24X7. Those connections are 
> dead expensive ... and are what your ISP is most likely purchasing, 
> then over subscribing to provide lower cost highly over subscribed 
> connections.
>
> Those that want 3mbps dedicated, need to purchase bonded T1's with a 
> dedicated SLA. The cost will range between $1-3K/month for the bonded 
> set. That will give you 3mbps all the time. If you are saving $1,500 a 
> month with your cable or DSL connection, and are happy that it's fast 
> most of the time, you are clearly getting a bargin at a huge savings.
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