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Re: Naive question on multiple TCP/IP channels and please dont start a uS NN debate here unless you really want to.

2015-02-06 12:25:38

Fine now how do you get the labeling/queueing across the AS boundary?  I
don’t know any ISP that accepts or recognizes the packet labeling of
another AS.



On 2/6/15, 12:28 PM, "Piers O'Hanlon" <p(_dot_)ohanlon(_at_)gmail(_dot_)com> 
wrote:


On 6 Feb 2015, at 16:57, Michael Richardson wrote:


Jim Gettys <jg(_at_)freedesktop(_dot_)org> 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_Managemen
t_Algorithms_DOCSIS_3_0.pdf

Piers


--
]               Never tell me the odds!                 | ipv6 mesh
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]   Michael Richardson, Sandelman Software Works        | network
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