Hello Damjan,
If you use PPPoE with a DSL modem in bridge mode(RFC 1483 BRIDGED) in order to
terminate a ppp tunnel on a linux box, it will not be easy to achieve QoS on
the upload side.
I was trying to do such a thing few weeks ago, but i notice that all QoS
algorythm under linux are made to work if the network device (for instance
ppp0 ) is able to give the accurate time needed to transmit each packet. And
it is not the case of an ppp device, all the packet will pass throw your QoS
because all queues created with tc will be empty: when a packet arrive on the
upload side on your ppp0, then pppd and the ppp kernel stuff will add an
8bits header (needed for pppoe) and send few micro second after your packet
on the ethernet device associated with the pppoe sesion.
As the queue of the QoS will almost always be empty, the QoS on ppp0 wont
work, because a QoS algorythm need to a choice between different class of
packet. By the way, you should notice that the queue of your modem will be
full and that QoS should be made on the modem with pppoe, not on the linux
box
I have made many test with as simple algorythm as PRIO, as with HTB and HFSC,
with slow ADSL link at 128kbit/s or 256kbit/s on the upload side.
In fact, all i said is true if you want to be able an almost perfect QoS, and
if you want to have a jitter (generated by the pppoe link) less gibber than
100ms. In my case i was willing to get less than 20ms over pppoe, for VoIP
(MGCP/SIP) application, and i failed the linux algorythm.
If 100ms is good for you try HFSC, with the rt option, it will be fine.
bye
Le Samedi 29 Octobre 2005 04:26, Damjan a écrit :> I need some suggestions, I want to limit the up and down bandwidth of PPPoE
> users that are terminated on a Linux router (kernel 2.6).
>
> What are my options, can I apply tbf qdisc on a ppp interface? That
> would limit the download, what about the upload?
>
> Any suggestions are welcome