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mhelmscpws568
Beginner

Modulation profile changes

Friday morning we changed the cable upstream modulation profile from profile 2 to profile one on all three of our CMTSs.

We also changed the upstream freq from 34208000 to 31008000 on some of the cards but not on this particular CMTS.

Saturday  morning we had 5 modems out of 3000+ go off line. They would try to  re-sync and get as far as (oi) or even (i) and then drop out and try to  sync gain. There was one modem that stopped at (rc)

changing the upstream modulation back to 2 on those ports brought the modems back online.

Can anyone explain to me why, only 5 out of the 3000+ modems went offline.

Here is the profiles in the config:

cable modulation-profile 1 request 0 16 0 8 qpsk scrambler 152 no-diff 64 fixed uw16
cable modulation-profile 1 initial 5 34 0 48 qpsk scrambler 152 no-diff 128 fixed uw16
cable modulation-profile 1 station 5 34 0 48 qpsk scrambler 152 no-diff 128 fixed uw16
cable modulation-profile 1 short 6 75 6 8 16qam scrambler 152 no-diff 144 shortened uw16
cable modulation-profile 1 long 8 220 0 8 16qam scrambler 152 no-diff 160 shortened uw16
cable modulation-profile 2 request 0 16 0 8 qpsk scrambler 152 no-diff 64 fixed uw8
cable modulation-profile 2 initial 5 34 0 48 qpsk scrambler 152 no-diff 128 fixed uw16
cable modulation-profile 2 station 5 34 0 48 qpsk scrambler 152 no-diff 128 fixed uw16
cable modulation-profile 2 short 5 75 6 8 qpsk scrambler 152 no-diff 72 shortened uw8
cable modulation-profile 2 long 8 220 0 8 qpsk scrambler 152 no-diff 80 shortened uw8

Any tohuoghts and suggestions will be appreciated
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