>>If I can restate that in a more concrete way: the queue may not drain at a >>smooth, constant rate. There are several real-world link technologies which >>exhibit this behaviour - wifi and DOCSIS come to mind, not to mention 3G/4G >>with variable signal strength.
This! Also, bottlenecks can move, such as when a DSLAMs backhaul reaches saturation for minutes/hours in the evenings as everyone tries to stream, and end-point connections drop to less than 50% of the local sync-rate worth of effective capacity. Therefore AQM settings about link capacity should be thought of as a Max not necessarily current link capacity. BTW- Amazing discussion, loving it. Jonathan Foulkes -----Original Message----- From: Bloat <[email protected]> On Behalf Of Jonathan Morton Sent: Friday, November 30, 2018 6:05 AM To: Luca Muscariello <[email protected]> Cc: bloat <[email protected]> Subject: Re: [Bloat] when does the CoDel part of fq_codel help in the real world? > On 30 Nov, 2018, at 12:32 pm, Luca Muscariello <[email protected]> > wrote: > > Two last comments: one should always used fluid approximation with > care, because they are approximations, the real model is more complex. Nobody > considers that the RTT varies during the connection lifetime and that ACK can > be delayed. > So CWD increases in a non simple way. If I can restate that in a more concrete way: the queue may not drain at a smooth, constant rate. There are several real-world link technologies which exhibit this behaviour - wifi and DOCSIS come to mind, not to mention 3G/4G with variable signal strength. - Jonathan Morton _______________________________________________ Bloat mailing list [email protected] https://lists.bufferbloat.net/listinfo/bloat _______________________________________________ Bloat mailing list [email protected] https://lists.bufferbloat.net/listinfo/bloat
