Re: QoS for PPPoE / ADSL

I have not done this scenario myself, so I don't suppose my response will be
as helpful as another. Appreciate this question Dale as it made me look up
a few things I had forgetten that I forgot. Thx!

Oh well ... hope these comments help.

For LLQ you should configure what you need and that's that. What does your
traffic need for the LLQ? Ok ... so ... configure it, guarantee it, and
you are cool (always!). If the line rate fluctuates, and you do not have
enough for your LLQ, then you need a diff line. Sorry for stating the
obvious ...

For the other traffic, my intial thoughts are that configuring the
class-default for wred is probably all you need. The other traffic will
battle it out in the individual queues, and traffic will be dropped when
needed.

LLQ for your important stuff, and wred for the rest. The important traffic
will get through and the other traffic will "come and go" as available
bandwidth provides.

Hope this is not too far off or too simplistic of an approach. Further, I
look forward to hearing yours and the other expert's opinions. Kindest
regards,

Andrew

On Sat, May 9, 2009 at 9:56 PM, Dale Shaw <dale.shaw_at_gmail.com> wrote:

> Hi all,
>
> Is there a nice solution for configuring CBWFQ and LLQ on PPPoE over DSL
> links?
>
> The issue is around triggering congestion through back-pressure with a
> parent shaper. In this asymmetric world where sync speed changes
> dynamically, how do you apply a output service-policy that matches the
> current upstream speed? I could use an arbitrarily low value, but then
> I'm ripping myself off in cases where I'm capable of sending more bps.
>
> I have a c1841 configured like so:
>
> Fa0/0 = LAN side
> Fa0/1 = connected to ADSL2+ modem @ 100FDX
>
> interface FastEthernet0/1
> load-interval 30
> speed auto
> full-duplex
> pppoe enable group global
> pppoe-client dial-pool-number 1
> no cdp enable
> !
> interface Dialer1
> mtu 1450
> bandwidth 1000
> bandwidth receive 12000
> ip address negotiated
> no ip redirects
> no ip proxy-arp
> ip flow ingress
> encapsulation ppp
> load-interval 30
> dialer pool 1
> dialer idle-timeout 0
> dialer persistent
> dialer-group 1
> no cdp enable
> ppp authentication chap callin
> ppp chap hostname username_at_isp.net
> ppp chap password secret123
> ppp ipcp route default
>
> Maybe I could use an EEM script to log in to my ADSL2 modem
> periodically and grab the rx and tx sync speeds, then dynamically
> update the 'bandwidth' statements on Dialer1 and modify the parent
> shaper configuration accordingly?
>
> Actually I assume a policy-map with 'shape average percent 100' in
> class-default would do the trick, as long as Dialer1's 'bandwidth'
> statements were correct.
>
> Hmm, has anyone done this? I can't afford an ADSL2 HWIC :-)
>
> cheers,
> Dale (currently sync'd at 1,236,000 up, 12,880,000 down)
>
>
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-- 
Andrew Lee Lissitz
all.from.nj_at_gmail.com
Blogs and organic groups at http://www.ccie.net