Par stvari o ADSL2+…
Ja koristim Thompson modem a ISP je Amis – dobro tu je i VOIP u igri ali svejedno.
Ovo su pojmovi koje ćete morati savladati a sve se manje /više svodi na udaljenost od centrale i kvalitetu linije/parice:
SN Margin (AKA Signal to Noise Margin or Signal to Noise Ratio)
Relative strength of the DSL signal to Noise ratio. 6dB is the lowest dB manufactures specify for modem to be able to synch. In some instances interleaving can help raise the noise margin to an acceptable level. The higher the number the better for this measurement.
6dB or below is bad and will experience no synch or intermittent synch problems
7dB-10dB is fair but does not leave much room for variances in conditions
11dB-20dB is good with no synch problems
20dB-28dB is excellent
29dB or above is outstanding
Line Attenuation
Measure of how much the signal has degraded between the DSLAM and the modem. Maximum signal loss recommendation is usually about 60dB. The lower the dB the better for this measurement.
20dB and below is outstanding
20dB-30dB is excellent
30dB-40dB is very good
40dB-50dB is good
50dB-60dB is poor and may experience connectivity issues
60dB or above is bad and will experience connectivity issues
Interleaving
When a customer is put on a "Noise Profile" usually their DSL line is changed from FastPath to Interleaved.
Interleaving is an error correction protocol that is implemented for your line at the DSLAM. With Interleaving enabled, the DSLAM can correct errors in the data stream it receives before passing that data to your gateway router. It is usually implemented on noisy or marginal lines and can greatly increase sync stability and effectively eliminate "first hop" packet loss. The largest drawback to Interleaving is that it will increase your ping time, specifically to your first hop gateway router.
If Interleaving is not enabled on your line, it is configured as FastPath. FastPath allows the DSLAM to pass the data received from you to the first hop router without performing any error correction. As a result, marginal lines could experience an increase in packet loss and decrease in sync stability (i.e. frequent sync loss). However, FastPath has lower ping times, especially to the first hop router.
Interleaving can also be provisioned automatically without human intervention when line quality drops below certain perimeters.
CRC Errors (Cyclic Redundancy Check)
CRC is a method of detecting errors in data transmission. A high CRC count in inself is not really cause for alarm. However, any increase in CRC errors after your initial connection is established is a problem and usually points to a physical issue somewhere between the modem and the DSLAM. Isolate your inside wiring as a cause by testing from the NID and troubleshoot from there.
Ovo je tek mali dio priče ali pojednostavljeno – svi koji koriste samo net neće imati večih problema ali oni koji igraju online sa podizanjem brzine iznad 4 mbps dolazi u igru povečanje pinga, ako Vam se promjeni modulacija sa G.992.1 Annex B na G.992.3 Annex B ili G.992.5 Annex B ping ide u nebo. Dakle net leti ali igranje online pa-pa…
I još jedna mala sitnica – ta tehnologija je jako osjetljiva na vremenske promjene – poglavito oluje – pad neta je garantiran – bar meni…..
I ja se veselim svemu boljem i jeftinijem ali mi dođe da se rasplačem kad pogledam recimo Šveđane koji (pazi sad) več paničare da treba ulagat više u infrastrukturu jer da će doči u bananu – a sad imaju net o kojem možemo samo sanjati…
Sad sam na 4 Mbps/768 kbps i ping hoda gore dolje….
Bio sam na 6 Mbps/768 kbps i ping je bio veči 50 %.....
A probali smo 8 Mbps/768 kbps i ping je otišao daleko iznad 100….
Link koji je dao tomifish2002 Vam ljepo predočuje problem udaljenosti…
http://www.internode.on.net/adsl2/graph/
Toliko od mene...
EDIT: možda se stvari malo poprave kad svima updateju firmware - (sad ga testiraju).