Acceptable Error rates

Currently monitoring a line with "issues". BT are involved and as yet have been unable to resolve the issues. It is believed to be a Modem/DSLAM issue rather than REIN or other external influences.

Every 30 minutes there is a massive spike in the latency - as shown in: Latency Spike

When this occurs there is an increase in the downstream errors: CRC increases by around 15-20, FEC by 1 or 2 and HEC by about 5. Occasionally the spike is a lot lower and just the upstream FEC increments by 2 or 3.

Reboots and resets do not change anything except the timing of the spikes - which are currently around 25 minutes apart, but could be up to 40 minutes and they seem to stay at the same spacing for quite a while and then suddenly change, so are "consistent". A reboot can alter them which points towards modem or DSLAM rather than an external influence.

So, ignoring the latency spikes themselves, is the general line performance acceptable with error rates of: CRC_dn 30/hr, FEC_dn 2/hr, HEC_dn 10/hr and FEC_up 4/hr ?

My home connection is very stable. It's been up for four days and four weeks.

I get;

CRC_dn 32/hr
FEC_dn 0 (throughout entire period)
HEC_dn 5/hr
FEC_up 56/hr

Raw stats are;

Noise Margin:		  5.6 dB		 15.3 dB
Attainable Rate:	74608 kbits/s		 26766 kbits/s
Actual Power:		 13.7 dBm		  1.1 dBm
Per Band Status:       	D1 	D2 	D3 	U0 	U1 	U2 	U3
Line Attenuation(dB):   4.6	14.2	26.2	3.4	14.8	21.9	N/A	
Signal Attenuation(dB): 7.0	14.1	26.3	3.4	14.1	20.8	N/A	
Noise Margin(dB):       5.6	5.7	5.6	15.3	15.4	15.3	N/A	
Total FECC:		0			 43489
Total ES:		4972			 1766
Total SES:		32			 0
Total LOSS:		3			 0
Total UAS:		892			 892
Total LPRS:		0			 0
Total LOFS:		21			 0
Total LOLS:		0			 0


 		  DS Channel1	  DS Channel0	US Channel1	  US Channel0
Speed (kbps):	          0	       78968	         0	       19999
SRA Previous Speed:       0	       79987	         0	       19999
Previous Speed:	          0	       79987	         0	       19999
Reed-Solomon EC:          0	           0	         0	       10720
CRC Errors:	          0	       24342	         0	        2033
Header Errors:	          0	        4053	         0	           0
Interleave (ms):       0.00	        0.00	      0.00	        0.00
Actual INP:	       0.00	        0.00	      0.00	        0.00

I'd say your error rates look good. They're much better than most of the FTTC connections I manage,

Have just had a look at the speeds ...

Downstream attainable is around 74400 kbps
Sync 63550 kbps

Actual around 60000 kbps

74400 Attainable looks high for a line of around 450-500 metres! Unless the noise level is incredibly low!

I think attainable is a bit of a guesstimate. On my connection I sync and achieve download significantly above the calculated attainable.

Those are some nicely presented line stats. What device are the produced from?

Paul

In reply to a post by youngsyp:

Those are some nicely presented line stats. What device are the produced from?

Paul

That's a Cisco 887VA-M-K9