On Oct 13, 2012, at 1:52 PM, Huan Pham <drie.huanp...@gmail.com> wrote:
> [HP] I think you can transmit at rate higher than the configured value if > theres no congestion (e.g. if there's no traffic waiting to be transmitted in > other queues). > > Here's the quote from Doc: > > [Juniper Doc] > rate-limit—(Optional) Limit the transmission rate to the rate-controlled > amount during congestion. In contrast to the exact option, when there is no > congestion, the scheduler with the rate-limit option shares unused bandwidth > above the rate-controlled amount. > > http://www.juniper.net/techpubs/en_US/junos9.5/topics/reference/configuration-statement/transmit-rate-edit-dynamic-profiles.html > > > [HP] Not mentioned in the Doc but I think in case of congestion, traffic is > is rate limited by being buffered, as opposed to being policed. I think it is > only dropped if its queue is full (or subject to RED). In other words, they > CAN BE queued if there is congestion and contention from different queues for > the bandwidth! > > Do you mean the queue buffer is always 0 when we use "rate limit" option? Hi Huan, Honestly, that's 9.5 documentation. Perhaps something changed at some point, but in current versions of code this is not how it works. I have taught this class for a few years now and have also worked w/ QoS on Junos for some time and the rate-limit option is used to limit the transmission rate to the specified amount. Take a look at the latest docs and you will see. I would say that your analogy of the queue buffer being 0 when using a transmit-rate w/ the rate-limit option is spot on. There is no buffering taking place. In other words, if you configured a transmit-rate of 0% with the rate-limit knob, all packets belonging to that queue would be dropped. Stefan Fouant JNCIE-SEC, JNCIE-SP, JNCIE-ENT, JNCI Technical Trainer, Juniper Networks Follow us on Twitter @JuniperEducate _______________________________________________ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp
