That's why you can use CB-WRED based on DSCP. Scheduling and congestion avoidance are two separate things.
On Tue, May 4, 2010 at 9:10 AM, Fabio Mendes <[email protected]>wrote: > I thought just like you: it is used only within classes. But I cannot grasp > the whole thing at all. > > In order to avoid tail droping when a queue reachs a certain threshold - > depending on the queue discipline - some packets are "ramdomly" discarded. > > If all the queues are avoiding tail droping, discarding some part of > incoming traffic and those two packets arrived, which one would be more > "likely" to be discarded ? AF marking plays no role in such a situtation ? > > > Thank you for answering. > > > On Tue, May 4, 2010 at 10:43 AM, Marko Milivojevic <[email protected]>wrote: > >> It depends... :-) What scheduler are you talking about exactly? Drop >> precedence is used to differentiate within the same class, not between >> the classes. AF11 is in CS1 and AF23 is in CS2... It's similar to >> scheduler chosing bananaes while being offered apples and oranges... >> :-) >> >> -- >> Marko Milivojevic - CCIE #18427 >> Senior Technical Instructor - IPexpert >> >> YES! We include 400 hours of REAL rack >> time with our Blended Learning Solution! >> >> Mailto: [email protected] >> Telephone: +1.810.326.1444 >> Fax: +1.810.454.0130 >> Web: http://www.ipexpert.com/ >> >> On Tue, May 4, 2010 at 13:21, Fabio Mendes <[email protected]> >> wrote: >> > >> > Suppose I have two packets: one marked as AF11 and another one marked as >> > AF23. >> > If the scheduler were to choose between one of them, which one would be >> ? >> > >> > Despite the fact that AF23 packet belongs to a queue that is suppose to >> get >> > a better queueing treatment it has the higher probability to be >> discarded. >> > In the other hand, AF11 packet belongs to a lower priority queue but it >> has >> > the lowest discarding probabability. >> > How does the scheduler decide which packet to send to the hardware queue >> ? >> > >> > >> > Thanks ! >> > -- >> > >> > _______________________________________________ >> > For more information regarding industry leading CCIE Lab training, >> please >> > visit www.ipexpert.com >> > >> > >> > > > > -- > > CCNA - Cisco Certified Network Associate > CCNP - Cisco Certified Network Professional > > "A bird that you set free may be caught again, but a word that escapes your > lips will not return." Jewish Proverb > > _______________________________________________ > For more information regarding industry leading CCIE Lab training, please > visit www.ipexpert.com > >
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