adsl apofthegmata

[V13]

Titlos: H poria mias ADSL

En arxh exoyme mia ADSL2+ apo 4net (ayto me ta 24Mbit).

Kefalaio 1 - Eisagogi:

* Kanoyme to speedtest kai dixnei taxytita to poly eos 700Kbps me synithes
times giro sta 400-500Kbps.

Kefalaio 2 - Mesa sto spiti:

* Pernoyme katsabidi, monotiki kai kati gia na mporoyme na pianoyme kalodia
(p.x. pensa). To teleytaio xreiazetai eidika ean exoyme ADSL.

* Episkeptomaste ola ta shmeia me mprizes mesa sto spiti ta opoia den pernane
apo ADSL filtro, h ta opoia einai sto dromo mexri to adsl modem. Anoigoyme
tis mprizes, ftiaxnoyme opoiesdipote enoseis den fainontai kales, mononoyme
otidipote gymno kai ta ksanaklinoyme.

* Episkeptomaste to shmeio sto opoio erxetai h grammh sto spiti (p.x. kapoio
ntoyi) kai to anoigoyme gia na doyme ean exei kamia enosi h tipote gymno.
Kanoyme kai ekei ta idia.

* Kanoyme to speedtest kai dixnei pleon stathero 1.5Mbps. Mia ayksisi 2-3
fores.

Kefalaio 3 - Sth polykatikoikia

* Pernoyme ta idia synerga + fako kai katebenoyme sthn eisodo ths oikodomis

* Anoigoyme to 'koyti' toy OTE kai blepoyme oti kai ekei epikratei ena mikro
xaos, alla oxi kati idiaitero.

* Me magika kolpa briskoyme poio apo ta kalodia afora emas. Pithanos tropos
einai to bale-bgale kalodia mexri na mas kopei to tilefono. Ean exete ena
polymetro kai ISDN mporeite na metrisete th tasi sta zeygaria kai na deite
poio exei megaliteri tasi (Sth periptosi moy ta kanonika eixan 50V kai to
ISDN 90V)

* Elegxete opoiesdipote enoseis den fainontai sostes, sfigkete *ligo* tis
bides klp. Ean deite opoiodipote gymno shmeio sto syrma sas, eite to mononete
(ean einai endiamesa), eite to bidonete kalitera (ean einai sto akro).
Elegxete gia pithanes enoseis sto diko sas syrma kai frontizete na tis
beltiosete ean xreiazetai kati tetoio. Telos, mononete opoiadipote enosi.

* (Extra bonus #1) Apomakrynete pithana alla gymna syrmata apo ta dika sas
oste na min dimioyrgoyn parasita

* (Extra bonus #2) Mononete ta akra (kapoia mporoyn na monothoyn) oste na min
yparxoyn parasita stis enoseis

* Epistrefete kai elegxete to speedtest. Me xara blepete oti tora bgazei
4-5Mbps stathera.

Kefalaio 3 - Paratiriseis:

* !!!PROSOXI!!! TA KALODIA TOY OTE EXOYN *REYMA*, EIDIKA EAN EXETE ISDN. MHN
TA PIASETE ME TO XERI. XREIAZESTE PENSES H KATI ALLO. 90V EINAI ARKETA GIA NA
ENERGOPOIHTHOYN/TINAXTOYN MONOI TOYS OI MYS SAS KAI NA PESETE APO TH SKALA
POY EISTE!!!

* Ta panta ta kanete me DIKIA SAS EYTHYNH! Exo thn entyposi pos o OTE den tha
xarei idiaitera an balete xeri sta kalodia toy. Mporei na einai kai en meri
paranomo, eidika ean mpleksete kai me toys ypoloipoys ths oikodomhs. Ektos
apo ta ergalia, xreiazeste kai ena kalo epixeirima toy styl: "Exo Internet
kai monono ta kalodia gia na beltioso th poiotita" etoimo (kati poy na to
katalabainei kapoios eykola, alla na einai kai arketa texniko), oste otan
perasei kapoios apo thn eisodo ths oikodomis kai sas rotisei, na min minei me
tin entyposi pos tin epomeni fora poy den tha doylevei to tilefono toy, h poy
h ADSL toy tha exei problima, tha ftete eseis.

Parartima A - Dieykriniseis:

* Ta 4Mbps apo to speedtest einai sth praksi giro sta 7-8Mbps taxytitas
exontas synypologisei to overhead. Min prospathisete na to ypologisete me
prakseis toy styl MTU+header*compression-ratio+FPA giati den exei noima kati
tetoio. Epeidi yparxei arketo packet loss, yparxoyn para polla
retransmissions, opote kai xanete arketo BW apo ekei. To whireshark ths
geitonias sas tha sas diksei gia posa retransmissions milame.

* To pragmatiko delay mporeite na to metrisete me xrisi toy SNMP, ean
ypostirizei kati tetoio o router sas, h apeytheias apo ton ypologisti, ean to
ppp termatizetai ston ypologisth.

* Epeidi akribos h perissoteri kinisi poy kanoyme einai TCP kai epeidi exoyme
packet loss kai arketa ypsilo delay, san kala paidia poy eimaste afieronoyme
ena Linux mixanima poy exoyme monima sto Internet gia na doylevei san proxy
(squid). Se ayto dinoyme:
echo "scalable" > /proc/sys/net/ipv4/tcp_congestion_control
Enalaktika, mporoyme na xrisimopoihsoyme kai ton 'hybla'.

Me to tropo ayto yparxei periptosi na exoyme aisthita kaliteres epidoseis pano
apo th idia ADSL grammi. Se emena me delay 42ms mexri ton proxy kai me mh
mhdeniko packet loss, h diafora itan aisthith. Fysika o proxy prepei na'xei
arketo bw oste na katebazei me th taxytita poy theloyme na mas ta stelnei
(p.x. na einai mesa sto EDET).

... hope it helps ...

<<V13>>

[V13]

On Tuesday 20 November 2007, V13 wrote:
> * Pernoyme katsabidi, monotiki kai kati gia na mporoyme na pianoyme kalodia
> (p.x. pensa). To teleytaio xreiazetai eidika ean exoyme ADSL.

Diorthosi... ISDN...

... sth synexeia pernoyme ena dikano kai pigainoyme sto typografeio na
katharisoyme oloys toys demones. Paralila, sigoyreyomaste oti mazi me ola ta
alla *DEN* exoyme parei kai tipota ligmena narkotika.

<<V13>>

[Christos Ricudis]

V13 wrote:
> * Anoigoyme to 'koyti' toy OTE kai blepoyme oti kai ekei epikratei ena mikro
> xaos, alla oxi kati idiaitero.
>
> * Me magika kolpa briskoyme poio apo ta kalodia afora emas. Pithanos tropos
> einai to bale-bgale kalodia mexri na mas kopei to tilefono. Ean exete ena
> polymetro kai ISDN mporeite na metrisete th tasi sta zeygaria kai na deite
> poio exei megaliteri tasi (Sth periptosi moy ta kanonika eixan 50V kai to
> ISDN 90V)
>

To klassiko kolpo einai na braxykyklwseis to loop sto diamerisma sou,
kai na metrhseis antistash sta zeygh tou katanemhth.

Ayto, bebaia, sthn periptwsh pou xrhsimopoieite thn kalwdiwsh ths
polykatoikias sas, kai oxi thn olokainouria CAT5 kalwdiwsh pou efere apo
to isogeio mexri ton pempto o prwhn sas geitonas.

> * Elegxete opoiesdipote enoseis den fainontai sostes, sfigkete *ligo* tis
> bides klp. Ean deite opoiodipote gymno shmeio sto syrma sas, eite to mononete
> (ean einai endiamesa), eite to bidonete kalitera (ean einai sto akro).
> Elegxete gia pithanes enoseis sto diko sas syrma kai frontizete na tis
> beltiosete ean xreiazetai kati tetoio. Telos, mononete opoiadipote enosi.
>

Epishs, kalo einai otan ksanaftiaxnete mia enwsh 25 etwn, na kobete ton
xalko poy xrhsimopoih8hke sthn palia kai na gymnwnete ligo kalwdio apo
thn arxh. Ta okseidia tou xalkou exei mikroterh agwgimothta apo to xalko :P

> * (Extra bonus #2) Mononete ta akra (kapoia mporoyn na monothoyn) oste na min
> yparxoyn parasita stis enoseis
>

Entaksei, twra to gamhses. To epomeno bhma einai na 8wrakiseis me plegma
ka8e zeygos kalwdiwn apo ton katanemhth mexri ton 13o orofo kai na
geiwseis to plegma - ennoeitai kai sta dyo shmeia, me koinh geiwsh 16
kare, pou katalhgei se rabdo xrusou 8ammenh sto edafos mesa se mia
ypogeia limnh pou kolympane sfairika xrysopsara.

> * !!!PROSOXI!!! TA KALODIA TOY OTE EXOYN *REYMA*, EIDIKA EAN EXETE ISDN. MHN
> TA PIASETE ME TO XERI. XREIAZESTE PENSES H KATI ALLO. 90V EINAI ARKETA GIA NA
> ENERGOPOIHTHOYN/TINAXTOYN MONOI TOYS OI MYS SAS KAI NA PESETE APO TH SKALA
> POY EISTE!!!
>

Apla den ta exeis piasei arketes fores. Synh8izetai.

> * Ta panta ta kanete me DIKIA SAS EYTHYNH! Exo thn entyposi pos o OTE den tha
> xarei idiaitera an balete xeri sta kalodia toy.

Den einai dika tou. H ey8ynh tou OTE teleiwnei sto shmeio pou to diko
tou akro termatizei sth regletta tou katanemhth ths polykatoikias.

[nde...@gmail.com]

On 11/21/07, Christos Ricudis <ric...@itc.auth.gr> wrote:
> [..]

> Epishs, kalo einai otan ksanaftiaxnete mia enwsh 25 etwn, na kobete ton
> xalko poy xrhsimopoih8hke sthn palia kai na gymnwnete ligo kalwdio apo
> thn arxh. Ta okseidia tou xalkou exei mikroterh agwgimothta apo to xalko :P

είναι ΠΟΛΥ ΠΟΛΥ καλό. Αν δεν θέλετε / μπορείτε να κόψετε τις
σκουριασμένες άκρες τουλάχιστον γυαλίστε τες γδέρνοντας τες με την
μύτη ενός ίσιου κατσαβιδιού