On 6 Feb 2015, at 16:57, Michael Richardson wrote: > > Jim Gettys <jg@xxxxxxxxxxxxxxx> wrote: >> What effect does this algorithm have in practice? Here are some examples: >> o real time isochronous traffic (such as VOIP, skype, etc) won't build >> a queue, so will be scheduled in preference to your bulk data. >> o your DNS traffic will be prioritized. >> o your TCP open handshakes will be prioritized >> o your DHCP & RA handshakes will be prioritized >> o your handshakes for TLS will be prioritized >> o any simple request/response protocol with small messages. >> o the first packet or so of a TCP transfer will be prioritized: remember, >> that packet may have the size information needed for web page layout in it. >> o There is a *positive* incentive for flows to pace their traffic (i.e. >> to be a good network citizen, rather than always transmitting at line rate). > >> *All without needing any explicit classification. No identification of >> what application is running is being performed at all in this algorithm.* > > This last part is I think the part that needs to be shouted at residential > ISPs on a regular basis. I wish that the IETF and ISOC was better able to > do this... in particular to ISPs which do not tend to send the right people > to NANOG/RIPE/etc. > Explicit class-based queueing is seeing fairly substantial deployment in some places - such as the UK - where for a few years now the default home routers (Thomson/Technicolor TG587/582 etc) for a number of the big ISPs (Plusnet, O2/Sky, Talk-talk and others) have shipped preconfigured with 5 queuing classes that classify traffic and provide for differing treatment. They also have some ALGs that work with SIP/H.323. I'm not aware of AQM enabled on the individual queues but at least they separate the traffic into different queues - albeit based on port number or ALG classifiers. Better than nothing anyway. Also the DOCSIS3.1 standard now mandates the use an AQM - namely PIE, though others can be implemented. I'm not sure where that is in terms of deployment though. There's a good report on it here: http://www.cablelabs.com/wp-content/uploads/2013/11/Active_Queue_Management_Algorithms_DOCSIS_3_0.pdf Piers > -- > ] Never tell me the odds! | ipv6 mesh networks [ > ] Michael Richardson, Sandelman Software Works | network architect [ > ] mcr@xxxxxxxxxxxx http://www.sandelman.ca/ | ruby on rails [ >