[linux] upload cez chello linku a interaktivita prace

[Lubomir Host]

Zdravim konferu.

Viem, ze zopar ludi z tejto konfery ma doma internet cez "chello", preto
by ich modhlo zaujimat nasledujuce riesenie nasledujuceho problemu: ak
nieco uploadujete smerom von, a pokusate sa popri tom interaktivne
pracovat cez ssh na serveri, je to prakticky nemozne kvoli prilisnej
latencii spojenia. Pritom ak nic neupladujete, je ping na urovni 8ms,
pri uploadovani ale aj 2000 - 10000ms (cize 2 az 10 sekund!).

Pri citani http://www.lartc.org/howto/lartc.qdisc.classless.html som
v sekcii 9.2.2.2 nasiel riesenie tohto problemu:

---------------------------------%<---------------------------------
tc qdisc add dev eth0 root tbf rate 128kbit latency 50ms burst 1540
---------------------------------%<---------------------------------

a vypnutie prikazom

------------%<------------
tc qdisc del dev eth0 root
------------%<------------

Rapidnu zmenu odozvy na ping pri zapnuti/vypnuti shapeovania vidno na
nasledujucich vypisoch na konci mailu.

Problem je v tom, ze sa preplna queue v chello modeme, a to sa prejavi
na interaktivite prace. Toto bola jedna z vlastnosti pripojenia , ktora
bola kritizovana v clanku PC Revue.

Ak by sa este niekomu chcelo experimentovat s optimalnym nastavenim
"rate" a "burst" parametrov v hore uvedenom prikaze, moze tak urobit.
Mne uvedene parametre zda sa vyhovuju (ine som ani neskusal ;-) a su to
parametre pre "chello light" - 1024/128 kbit (pred zvysenim rychlosti
stahovania dna 1. aprila 2005 bol linka 512/128 kbit).

Uz len keby nebolo potrebne sem-tam restartovat modem. ;-)

S pozdravom Lubomir Host alias 'rajo'


Este slubene vypisy...

Zapnutie shapingu:

-------------------------------------%<-------------------------------------
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=59 ttl=57 time=1951 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=60 ttl=57 time=1912 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=61 ttl=57 time=1772 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=62 ttl=57 time=1064 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=63 ttl=57 time=270 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=64 ttl=57 time=319 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=65 ttl=57 time=177 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=66 ttl=57 time=137 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=67 ttl=57 time=9.84 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=68 ttl=57 time=30.9 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=69 ttl=57 time=8.51 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=70 ttl=57 time=44.8 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=71 ttl=57 time=8.14 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=72 ttl=57 time=7.72 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=73 ttl=57 time=30.6 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=74 ttl=57 time=6.87 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=75 ttl=57 time=82.2 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=76 ttl=57 time=21.9 ms
-------------------------------------%<-------------------------------------

Vypnutie shapingu:

-------------------------------------%<-------------------------------------
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=281 ttl=57 time=35.8 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=282 ttl=57 time=9.48 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=283 ttl=57 time=61.0 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=284 ttl=57 time=14.3 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=285 ttl=57 time=62.3 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=286 ttl=57 time=29.4 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=287 ttl=57 time=13.0 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=288 ttl=57 time=240 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=289 ttl=57 time=406 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=290 ttl=57 time=462 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=291 ttl=57 time=601 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=292 ttl=57 time=748 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=293 ttl=57 time=805 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=294 ttl=57 time=949 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=295 ttl=57 time=911 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=296 ttl=57 time=1064 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=297 ttl=57 time=1115 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=298 ttl=57 time=1079 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=299 ttl=57 time=1222 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=300 ttl=57 time=1272 ms
64 bytes from test.domena.sk (1.2.3.4): icmp_seq=301 ttl=57 time=1234 ms
-------------------------------------%<-------------------------------------

-- 
Lubomir Host 'rajo' <rajo AT platon.sk>        ICQ #:  257322664
Platon Software Development Group              http://platon.sk/
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