On 3/9/06, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote: > Thanks a lot Soo-Hyun, I agree that a definitive answer is inexistent, > as much as the perfect weights value. I have asked for some researchers > which has investigated in bandwidth reservations on DiffServ approach, > and only one requested me, bit_rate/10. However, the ns-2 does not > accept 0.x values, it gives Floating point exception, so 0.002 is not > accepted by the ns-2, only from 1.
Although there is not likely a definitive answer for every RED case about the parameters, there is abviously a recommended answer. :-) I am having RED simulations with a floating point q_w value without any problem under ns-2.28. So you should not have "Floating Point Exception" error by using some floating point values for the queue weight setting. If you have changed "double q_w" to something like "TracedDouble q_w" in red.h, you may want to replace it to the original declaration. Soo-Hyun > > Regards, > > Augusto > > > > Quoting Soo-Hyun Choi <[EMAIL PROTECTED]>: > > > On 3/9/06, Augusto Neto <[EMAIL PROTECTED]> wrote: > >> Hi, > >> > >> The reasons for configurarion fo the RED parameters given by Mrs. Sally > >> Floyd, as could see, takes into account the queue management goal. > >> Decisions > >> about the dynamically set of the weights are not clear in the text, at > >> least > >> considering QoS. Moreover, it is older than the DiffServ :-) that was > >> standardized in 1998. > > > > That's right. Its goal is to have a proper queue management, and it > > did not address about the parameter settings dynamically. However, I > > became to understand how I set the parameters dynamically by reading > > the article. > > > >> My problem concerns on choosing the correct value to set the per-queue > >> weights according to the bit rate of a flow. For instance, my work consider > >> that before the adimition of a flow it is necessary to reserve resources > >> for > >> it, its bit rate in the case. So, if the bit rate is 3Mb I need to > >> configure > >> the scheduler to reserve 3Mb. In ns-2 the reservation concerns in setting > >> the weights correct? > >> > > > > RED is exceptionally parameter senstive, and it is hard to say which > > values are right for a particular case, as you may know. There are > > normally 4 important parameters though. > > > > 1) max thresh: maxthresh = queue_size / 2 > > 2) min thresh: minthresh = maxthresh / 3 > > 3) max_p: max_p = 2 * packet_loss_rate > > 4) q_w: no definitive answer, but it is almost fine if you leave it to > > 0.002 (ns-2 default value) > > > > This is regarded as a general rule to set the RED paramemters for a > > simulation, but not for the real world. > > > > Soo-Hyun > > > > > >> Regards > >> > >> Augusto > >> > >> ----- Original Message ----- > >> From: "Soo-Hyun Choi" <[EMAIL PROTECTED]> > >> To: "Augusto Neto" <[EMAIL PROTECTED]> > >> Sent: Wednesday, March 08, 2006 3:59 PM > >> Subject: Re: RED parameters configuration > >> > >> > >> > Hi, > >> > > >> > I think you'd better read this. > >> > http://www.icir.org/floyd/REDparameters.txt > >> > > >> > Soo-Hyun > >> > > >> > On 3/8/06, Augusto Neto <[EMAIL PROTECTED]> wrote: > >> >> Dear Soo > >> >> > >> >> I need to choose the correct value for weights of RED queues in > >> >> DiffServ. > >> >> For instance, what is the correct value of the weights to be configured > >> >> for > >> >> a flow with 1Mb of bit rate? > >> >> Regards, > >> >> > >> >> Augusto > >> >> > >> >> ----- Original Message ----- > >> >> From: "Soo-Hyun Choi" <[EMAIL PROTECTED]> > >> >> To: "ben" <[EMAIL PROTECTED]> > >> >> Cc: "ns-users" <ns-users@ISI.EDU> > >> >> Sent: Tuesday, March 07, 2006 4:00 AM > >> >> Subject: Re: [ns] RED queue grows beyond limit on ns-2.28-9 > >> >> > >> >> > >> >> > > >> >> > You need to set the queue size by modifying the following two lines. > >> >> > > >> >> > $ns queue-limit $node_(r1) $node_(r2) 100 > >> >> > $ns queue-limit $node_(r2) $node_(r1) 100 > >> >> > > >> >> > > >> >> > On 3/7/06, ben <[EMAIL PROTECTED]> wrote: > >> >> >> Hi Soo-Hyun Choi, > >> >> >> > >> >> >> I attached the output of the xgraph in ps format. > >> >> >> 1. red.ps - red.tcl run on ns2.27 in fedora core 4 > >> >> >> 2. red2.ps - the same red.tcl on ns2.28 in fedora > >> >> >> core4 > >> >> >> > >> >> >> In previous post, I wrote the limit is 100. It is > >> >> >> mistake, it is infact limit_ is equals to 25. > >> >> >> > >> >> >> > >> >> >> In the first part the current queue is below 25 > >> >> >> packets. However, in the second part, the red queue > >> >> >> just grow beyond 25 packets. > >> >> >> > >> >> >> > >> >> >> Cheers, > >> >> >> > >> >> >> > >> >> >> --- Soo-Hyun Choi <[EMAIL PROTECTED]> > >> >> >> wrote: > >> >> >> > >> >> >> > The instantaneous RED queue size shouldn't grow > >> >> >> > beyond the actual RED > >> >> >> > queue size, and the average RED queue size shouldn't > >> >> >> > grow beyond the > >> >> >> > maxthresh. > >> >> >> > > >> >> >> > You may want to check your parameters again. > >> >> >> > > >> >> >> > On 3/7/06, ben <[EMAIL PROTECTED]> wrote: > >> >> >> > > > >> >> >> > > Hi ns users, > >> >> >> > > > >> >> >> > > I some doubt about the RED Queue. I run a > >> >> >> > > simple tcl script ( can be download from > >> >> >> > > http://nile.wpi.edu/NS/Example/red.tcl) for RED > >> >> >> > queue > >> >> >> > > with 2 TCP sources. I observed that the RED queue > >> >> >> > just > >> >> >> > > grow beyond the limit (it is set to 100 packets in > >> >> >> > the > >> >> >> > > tcl script) when run on ns-2.28, ns-2.28 with > >> >> >> > eurane > >> >> >> > > extension and ns-2.29 . > >> >> >> > > > >> >> >> > > It is perfectly ok when run on ns-2.27 and ns-2.26 > >> >> >> > > with eurane extension. Any comment on this? > >> >> >> > > > >> >> >> > > p/s: I'm using fedora core 4 and cygwin on windows > >> >> >> > > > >> >> >> > > Ok cheers, > >> >> >> > > > >> >> >> > > Ben > >> >> >> > > Master Student. > >> >> >> > > > >> >> >> > > Send instant messages to your online friends > >> >> >> > http://uk.messenger.yahoo.com > >> >> >> > > > >> >> >> > > > >> >> >> > > >> >> >> > >> >> >> Send instant messages to your online friends > >> >> >> http://uk.messenger.yahoo.com > >> >> >> > >> >> >> > >> >> > > >> >> > > >> >> > >> >> > >> >> > >> > >> > >> > > > > > > ---------------------------------------------------------------- > This message was sent using IMP, the Internet Messaging Program. > >
