Kitz Forum
Broadband Related => Broadband Technology => Topic started by: tiffy on August 21, 2020, 05:13:51 PM
-
Have recorded some observations on the 3 VDSL-2 lines I monitor, same exchange, 3 different Huawei DSLAM's with the objective of trying to determine what criteria DSL applies with respect to application of G.Inp Re-Tx high/low profiles.
The 2 main parameters recorded being DS FEC's and G.Inp LEFTRS error rate but taking into consideration DS interleaving depth and INP.
Line 1, PN 40/10 service, consistantly running on G.Inp Re-Tx low profile.
DS Interleaving 16, INP 48, FEC's, low, G.Inp LEFTRS error rate high.
Medium length of the 3 lines and exibits the highest DS & US ES and SES errors by far.
DS synch approx. 35 Mbps, stable connection.
Line 2, PN 40/10 service, consistantly running on G.Inp Re-Tx high profile.
DS Interleaving 4, INP 50, FEC's, much higher than line 1, G.Inp LEFTRS error rate very low.
Longest length of the 3 lines and exibits practically zero DS & US ES and SES error rates.
DS synch approx. 39 Mbps, stable connection.
Line 3, BT 80/20 service, consistantly running on G.Inp Re-Tx high profile.
DS Interleaving 8, INP 50, FEC's, higher than line 1, G.Inp LEFTRS error rate low.
Shortest length of the 3 lines and exibits minimal DS & US ES and SES error rates.
DS synch approx. 70 Mbps, stable connection.
Have attempted to get my service (line 2) back to G.Inp Re-Tx low profile by applying DS capping to the modem over a few weeks period, has not worked, has always run on Re-Tx low profile until approx. 6 months ago.
Surprised that the line which exibits the worst performance and highest error rates, with the exception of FEC's (line 1) is the only line which has consistantly remained on Re-Tx low profile.
I have always been inclined to ignore FEC rate as errors which had been "fixed" before impacting line performance, however, purely by comparative observation of the 3 lines a low FEC rate and to a lesser extent a high LEFTRS error rate would appear to be factors which have an impact on G.Inp Re-Tx profile.
I fully appreciate that the component values listed are only comparative and there are very likely a lot of other factors to be considered before the mysterious working of DLM with respect to parameter can be fully fathomed out.