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locate source of uncorrectables

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bama2545
locate source of uncorrectables

I am just wondering if ya'll have an easier way of locating a modem(s) that is putting out a lot of uncorrectable data on the upstream port. Currently I use a mib browser and query all the modems on that particular upstream port looking for uncorrectable amounts that stick out, document them and then recheck a few minutes later. This can be very time consuming on certain nodes that have 200 or so modems. Any suggestions on an easier way to do this. Also, do ya'll have any daily tasks that you perform on the cmts side of the network? I was put into this position when the company decided it was time to offer a broadband service and only have a few weeks training from motorola. I have been winging it ever since, picking up things here and there.

Thanks

cmcaldas
Uncorrectables

it's not often the cause is a cable modem that's causing that. it tends to be return plant. what's the snr and microreflections? what modulation and channel width is your return configured for? how many nodes are combined to the receiver (have you tried to move nodes to another port to see if the problem follows?) .
What command are you using to check?
example ( run 4 or 5 times to see changes)
sh int cable 0/0 upstream 3 signal-quality
ifIndex 7
includesContention 0
unerroreds 222586352
correctables 4252292
uncorrectables 981962
signalToNoise 244
microReflections 29
equalData FF.F0.FF.A2.00.44.00.5D.FE.9D.FE.EF.3F.3D.00.00.FF.A4.00.2D.00.42.FF.95.00.34.00.A6.FF.D6.FF.F9

Also sh stats sum error (sid or slot number)

bama2545
This trouble we had

This trouble we had yesterday is on a new node. It only has about 10 customers on it. It had greater that 1% uncorrectable data on it according to the solarwinds software that we use. I pulled the uncorrectables from the mib browser and saw that this one modem had 77,387 uncorrectables and ping the modem was getting response times ranging from 1200ms to 1600ms. All other modems were around 16ms to 30ms. Signal levels on this modem were -2 and 43 I believe. Tech hooked up his meter and I pinged the modem in it all was good. Hooked the original modem back up and it was ok again. We swapped that modem out so I can test it. Looking at the return path using Trilithic SST, it looks clean. Now to answer you questions. We combine 2 nodes per upstream (I hate that) and each node passes 500 homes. In the past we have switched upstream ports and the trouble follows leading to outside plant issues which is usually the case. We are using modulation profile 1 - 16qam, 3.2mhz wide, 2.56 symbol rate, and frequency of 32mhz. Also we are docsis 1.1 if that matters.

ifIndex 360707
includesContention 0
unerroreds 33899269
correctables 608012
uncorrectables 308488
signalToNoise 277
microReflections 28
equalData FF.E1.00.01.00.A4.00.B4.FE.82.FE.93.3F.46.00.00.FF.D1.FF.D0.00.1A.00.9A.FF.AC.00.12.00.3F.FF.AD
64000:7A#show int cable 5/0 upstream 2 signal-quality
ifIndex 360707
includesContention 0
unerroreds 33899567
correctables 608015
uncorrectables 308489
signalToNoise 286
microReflections 28
equalData FF.C5.00.07.00.B3.00.76.FE.76.FE.B4.3E.C0.00.00.00.1E.00.3F.FF.FF.00.A1.FF.85.00.0B.00.4A.FF.DE
64000:7A#show int cable 5/0 upstream 2 signal-quality
ifIndex 360707
includesContention 0
unerroreds 33899882
correctables 608015
uncorrectables 308489
signalToNoise 277
microReflections 28
equalData FF.CC.00.1E.00.AF.00.79.FE.B1.FE.C7.3E.70.00.00.00.6F.00.28.FF.D0.00.A9.FF.9C.00.39.00.38.FF.D7
64000:7A#show int cable 5/0 upstream 2 signal-quality
ifIndex 360707
includesContention 0
unerroreds 33900483
correctables 608027
uncorrectables 308491
signalToNoise 286
microReflections 28
equalData FF.E3.00.10.00.93.00.93.FE.8C.FE.87.3E.61.00.00.00.17.00.5F.FF.EB.00.7A.FF.B6.00.23.00.4A.FF.EA
64000:7A#show int cable 5/0 upstream 2 signal-quality
ifIndex 360707
includesContention 0
unerroreds 33902777
correctables 608061
uncorrectables 308502
signalToNoise 284
microReflections 29
equalData FF.DB.00.07.00.9A.00.72.FE.C1.FE.B0.3E.BB.00.00.00.66.00.5C.FF.C8.00.AA.FF.98.00.24.00.19.FF.BF

64000:7A#show stats sum error slot 5
MAC Address I/F SID CorrFec CorrFec UnCorrFec UnCorrFec
Count Ratio Count Ratio
0019.5edc.5c84 5/0/U2 134 2868 0.00513252 0 0.00000000
0019.5ee8.12a6 5/0/U2 109 5864 0.02001748 0 0.00000000
0019.5ef9.0382 5/0/U2 135 1166 0.00714829 0 0.00000000
001a.665c.6348 5/0/U2 102 41 0.00052986 0 0.00000000
001a.6660.e4ca 5/0/U2 141 20565 0.02007981 0 0.00000000
001a.6663.2efc 5/0/U2 108 8108 0.01069812 0 0.00000000
001a.6663.58a8 5/0/U2 140 6492 0.00488744 0 0.00000000
001a.6665.ec18 5/0/U2 133 7489 0.02394496 0 0.00000000
001a.668b.1522 5/0/U2 94 10009 0.01330805 0 0.00000000
001a.668b.1a24 5/0/U2 111 21685 0.01555205 0 0.00000000
64000:7A#show stats sum error slot 5
MAC Address I/F SID CorrFec CorrFec UnCorrFec UnCorrFec
Count Ratio Count Ratio
0019.5edc.5c84 5/0/U2 134 2868 0.00513251 0 0.00000000
0019.5ee8.12a6 5/0/U2 109 5864 0.02001741 0 0.00000000
0019.5ef9.0382 5/0/U2 135 1166 0.00714824 0 0.00000000
001a.665c.6348 5/0/U2 102 41 0.00052985 0 0.00000000
001a.6660.e4ca 5/0/U2 141 20639 0.02010664 0 0.00000000
001a.6663.2efc 5/0/U2 108 8108 0.01069808 0 0.00000000
001a.6663.58a8 5/0/U2 140 6492 0.00488744 0 0.00000000
001a.6665.ec18 5/0/U2 133 7489 0.02394488 0 0.00000000
001a.668b.1522 5/0/U2 94 10009 0.01330804 0 0.00000000
001a.668b.1a24 5/0/U2 111 21685 0.01555204 0 0.00000000
64000:7A#

The modem new modem for this customer is 001a.6660.e4ca. Looking at this modem's uncorrectables in the mib browser (1.3.6.1.2.1.10.127.1.3.3.1.12) show 10,370 in 24 hours. I just got to checking and ping times are bad again 1000ms - 1200ms. Levels according to the modem are DS snr 41, Rec Pow - 0, Trans Pow 45, and US snr 27. I don't think it is the modem now and probably something at the house is messing with it like a a bad dc or video filter. On that command that shows the corrFEC count and uncorfec, shouldn't I see something if that modem is running uncorrectables right now?