QoS for PPPoE / ADSL

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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Received on Sun May 10 2009 - 11:56:53 ART