QoS σε router με linux firmware για καλύτερο VoIP

[V13]

On Wednesday 11 March 2009, Yiannis Yiakoumis wrote:
> > To problhma den brisketai sta well-behaved flows :)
>
> den nomizw oti udp traffic sou dimiourgei idiaitero provlima gia na
> asxolitheis na to kopseis. exeis dokimasei shaping me ack drops kai den
> doulepse? exw tin entipwsi oti oloi oi ISP pou kovoun ta P2P petiximena me
> ayto to kanoun. kai fantazomai an theleis na to kaneis genikologo tou stil
> "kopse ayta ta ip" kai den mplekseis me application identification, toso to
> kalitero.

To na kaneis traffic shaping kanontas drop orismena ACK einai 100% sigoyro pos 
den tha exei ta apotelesmata poy perimeneis:

a) Ta ACK einai cumulative, opote apo th stigmi poy to window size tha ginei 
4*MSS (me 150ms RTT ayto shmainei ~ 120-320 Kbps), akomi kai an rixneis ena 
sta dyo ACK (poly megalo pososto) kai akomi kai an efarmozontai ta delayed 
ACKs, den tha exeis kanena apotelesma (ektos kai an ksexnao kati). Ara tha 
dhmioyrgiseis problima stis arges syndeseis kai tha eynoiseis aytes poy trone 
to perissotero b/w.

b) Ean soy doylepsei tha eisai pio evalotos sta problimata toy ISP soy h toy 
ISP toy ISP soy (klp) o opoios kata pasa pithanotita (p.x. forthnet) tha exei 
to diko toy bottleneck kai epomenos ta dika soy sessions tha einai se 
ypodeesterh moira apo olon ton ypoloipon.

c) Ta apotelesmata poy tha exeis tha einai entelos tyxaia. P.x. den tha 
ksereis gia poio logo ta exeis, tha doylevoyn mono th mera k.a.

Ayto poy mporeis na kaneis (den diabasa olo to thread opote den ksero an 
ypothike) einai na exeis ena linux me dyo interfaces kai na kaneis traffic 
shaping sthn ekserxomenh kinisi toy kathe interface, bazontas san ano orio to 
orio ths grammhs soy (an einai DSL, th taxythta sthn opoia doylevei).

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