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Date:      Tue, 17 Oct 2000 22:19:01 -1000 (HST)
From:      Vincent Poy <vince@oahu.WURLDLINK.NET>
To:        Len Conrad <lconrad@Go2France.com>
Cc:        freebsd-questions@FreeBSD.ORG
Subject:   Re: Best DSL Router?
Message-ID:  <Pine.BSF.4.21.0010172214230.1344-100000@oahu.WURLDLINK.NET>
In-Reply-To: <5.0.0.25.0.20001016224843.048dd3d0@mail.Go2France.com>

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On Mon, 16 Oct 2000, Len Conrad wrote:

> >         As a followup, please discuss this on the following thread on the
> >newsgroups: ba.internet and comp.dcom.xdsl:
> >
> > >How will this
> > >help and is it with all ADSL implementations or only with PacBell since
> > >I noticed Cable Modems doesn't exhibit this problem.
> >
> >Cable modems do exhibit the problem when they are running at an upstream
> >cap -- the problem can happen with TCP/IP on *any* asymmetric link.
> 
> ok, cool.  The pb is not upstream "robbing" bandwidth from 
> downstream, (ie, they are truly independent channels/media allowing 
> full duplex) but bad congestion the slow channel slowing/blocking 
> tcp/ip protocol responses awaited by the fast channel.

	I guess maybe if the up channel has slightly more bandwidth, the
problem might not be as evident.  

> > >Also, is ADSL
> > >technically full duplex or is it half duplex?
> >
> >Full duplex.
> 
> ok
> 
> > >From what Netopia and
> > >Cisco told me, ADSL is Assynchronous and not Synchronous like the other
> > >xDSL implementations.  Thanks for any input you can provide.
> >
> >ADSL is synchronous.
> 
> asymmetric, not asynchronous  vbg

	Hehe, Asynchronous doesn't sound right since I thought only Analog
modems used Asynchronous.

> >         So I guess
> 
> "guess" ?  vbg

	Heh, what does vbg mean?

> >you were right that ADSL is Full Duplex but just
> >because it's Full Duplex doesn't mean that you will get the advertised
> >speeds simultaneously in both directions.
> 
> You were right about the slowdown but wrong about the reason.

	Yeah, but someone mentioned that traffic shaping can fix the
problem.  The only problem is how would this work if a Ethernet card has
two IP's binded with one of them being dynamic and you only want to 
traffic shape on the dynamic IP and not the inernal LAN?

> And we both learned a few points. Well, I learned one, you learned 
> more than one, "asymmetric learning", but don't let me slow you down!!  LOL

	Heh... That Assymmetric doesn't mean assymmetric when it comes to
Verizon/GTE's Silver ADSL which is 384k/384k or 768k/768k =)

> Thanks for the follow through, very helpful.  The Paradyne book still 
> applies and will help build street cred at the next geek cocktail 
> party, even if Paradyne doesn't lead the market.

	Heh, it's kinda interesting.  Maybe it's PacBell who is doing
something on their end for all we know to prevent people from using too
much bandwidth.  Run a server, say slow down to the downloads! LOL


Cheers,
Vince - vince@WURLDLINK.NET - Vice President             ________   __ ____ 
Unix Networking Operations - FreeBSD-Real Unix for Free / / / / |  / |[__  ]
WurldLink Corporation                                  / / / /  | /  | __] ]  
San Francisco - Honolulu - Hong Kong                  / / / / / |/ / | __] ]
HongKong Stars/Gravis UltraSound Mailing Lists Admin /_/_/_/_/|___/|_|[____]
Almighty1@IRC - oahu.DAL.NET Hawaii's DALnet IRC Network Server Admin




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