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thomson cable modem

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servicenet
thomson cable modem

Hi,

I have a new thomson cable modem, the cm gets a ip adres, the cpe gets no ip adres. What may be the reason?

grosche
dhcpd

can you check if a dhcp discover arrives at the dhcp server and the dhcp server send an dhcp offer?
use tcpdump under linux on the dhcp server.

tcpdump -i ethX port 67

servicenet
thomson

I realy dont know anymore, on a working walloutlet (arris modem 1.1) i put in the thomson, DS light is on but thats all. Tryed 4 modems. Modem can''t find downstream i think. The arris modem will connect.

Any suggestion?

grosche
All Thomson CM

Are the 4 modems you have tested all thomson? All the same model?
Which model? What for a CMTS?
I think you have an upstream problem. Perhaps too little noise distance.
Perhaps not supported modulation in thomson modem. All Modems are Docsis 1.1?
Do you use Eurodocsis or Docsis?
Change the upstream frequency in the CMTS. Change the Modulation Profile.
Change the Upstream Port in the CMTS. Try an other CM.
Print the Thomsen CM Log.
Print your CMTS config.

servicenet
Online

Thx, afther setting the upstream power to 0 the modems came online. This is the output of the modem.

Downstream Channel
Lock Status Locked Modulation QAM256
Channel ID 11 Symbol rate 5360537
Downstream Frequency Downstream Power 21.4 dBmV
SNR 38.4 dB

Upstream Channel
Lock Status Locked Modulation QPSK
Channel ID 1 Symbol rate 1280 Ksym/sec
Upstream Frequency Upstream Power 38.3 dBmV

grosche
Power Level

Okay.
The Downstream Power Level is too High.
Values should be between -13 dBmV (47 dBµV) and max. +17 dBmV (77 dBµV). Perfect so +6 dBmV (66 dBµV).
The Upstream Power Level is good.
Values should be between +30 dBmV (90 dBµV) and max. +50 dBmV (110 dBµV). Perfect so +40 dBmV (100 dBµV).
Then the modem has a reserve of 10 dBmV to the top and the SNR is not bad.
On the CMTS Upstream Port the Power Level should be so +6 dBmV.
Your Value is +0 dBmV. +6 dBmV would be better. Then you're a larger noise distance.
Reinforce the Upstream Signal at the amplifier or reduce the Attenuation.

How much was the Upstream Power Level on the CMTS Port before?

servicenet
downstream

The downstream power is set to 610, now i have i set to 500.

The upstream on the cmts

Channel Status Speed In Octets Mod Profile Frequency Power Window
------- ------- --------- ---------- ----------- --------- ----- ------
4 up 2560000 841259075 1 29000000 5 60
5 up 320000 6479731 1 29000000 26 60
6 up 2560000 2773936338 1 8000000 40 60
7 up 2560000 1415705439 1 8000000 6 60
8 down 0 0 1 10750000 260 60
9 down 0 0 1 10750000 260 60
10 down 0 0 1 10750000 140 60
11 down 0 0 1 10750000 260 60

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