Hi
I am trying to use frequencies higher than 42Mhz in an Upstream port of the CMTS C100G Casa Systems.
Add in my network some Ubee EVW3226 modem that support (5-85Mhz), they have eight bonded downstream channels and
four bonded upstream channels
with AttributeMask in the docsis file I indicate to this cable modem model that it only use the 4 frequencies higher than 42Mhz
In this same port I also use other cable modem models that only support (5 - 42Mhz)
this works fine. I am testing with 7 modem Ubee EVW3226
My intention is to use frequencies higher than 42Mz to have a higher SNR in these channels.
The initial result is the opposite of what I expected, the channels with frequencies below 42Mhz have a higher SNR than the channels with frequencies above 42Mhz
CASA-C100G#show docsis upstream channel utilization | include 12/14
12/14.0 (81000000 Hz) 30.7 0 0 6 Independencia-7
12/14.1 (74600000 Hz) 30.7 0 5 2 Independencia-7
12/14.2 (68200000 Hz) 30.7 0 0 6 Independencia-7
12/14.3 (61800000 Hz) 30.7 0 2 3 Independencia-7
12/14.4 (40100000 Hz) 15.4 21 32 85 Independencia-7
12/14.5 (36900000 Hz) 15.4 19 36 80 Independencia-7
12/14.6 (33700000 Hz) 15.4 19 32 82 Independencia-7
12/14.7 (30500000 Hz) 15.4 22 23 90 Independencia-7
CASA-C100G#show upstream signal-quality | include 12/14
12/14.0/0 28.3
12/14.0/1 0.0
12/14.1/0 29.1
12/14.1/1 0.0
12/14.2/0 30.2
12/14.2/1 0.0
12/14.3/0 29.6
12/14.3/1 0.0
SNR of frequencies below 42Mhz (Greater than the 4 initials that are higher)
12/14.4/0 33.1
12/14.4/1 0.0
12/14.5/0 34.4
12/14.5/1 0.0
12/14.6/0 33.7
12/14.6/1 0.0
12/14.7/0 33.7
12/14.7/1 0.0
CASA-C100G#
The Cable Modem in the higher frequencies increased 9 dB in RxPwr,
this forces me to change the power-level to 0 in these 4 channels, in the channels lower than 42Mhz power level is 8.
This is the current configuration that I am using on this port where I am testing,
please check to know what I can change to increase the SNR of frequencies above 42Mhz
What do you recommend me to do in the CMTS and in the Network
Configuration of the port with which I am testing
CASA-C100G#show interface upstream port 12/14
interface upstream 12/14.0
description "Independencia-7"
spectrum-rule 1
frequency 81000000
channel-width 6400000
power-level 0
no fast-carrier-offset
power-adjustment continue 2
power-adjustment threshold 1
voice-bw-reserve 75 emergency 0
rate-limit
ingress-cancellation
partial-service fec-threshold 1
partial-service snr-threshold 0
no small-signal-compensation
logical-channel 0 description "Independencia-7"
logical-channel 0 prov-attr-mask 0xFFFF
logical-channel 0 channel-width 6400000
logical-channel 0 profile 64 secondary-profile 16,10
logical-channel 0 minislot 1
logical-channel 0 data-backoff automatic
logical-channel 0 ranging-backoff 2 8
logical-channel 0 pre-equalization 1440
no logical-channel 0 post-equalization
logical-channel 0 power-offset 0
logical-channel 0 ranging-priority 0x0
logical-channel 0 class-id 0x0
no logical-channel 0 shutdown
logical-channel 1 prov-attr-mask 0x0
logical-channel 1 channel-width 6400000
logical-channel 1 profile 3
logical-channel 1 minislot 1
logical-channel 1 data-backoff automatic
logical-channel 1 ranging-backoff 0 4
no logical-channel 1 pre-equalization
no logical-channel 1 post-equalization
logical-channel 1 power-offset 0
logical-channel 1 ranging-priority 0x0
logical-channel 1 class-id 0x0
logical-channel 1 shutdown
no shutdown
interface upstream 12/14.1
description "Independencia-7"
spectrum-rule 1
frequency 74600000
channel-width 6400000
power-level 0
no fast-carrier-offset
power-adjustment continue 2
power-adjustment threshold 1
voice-bw-reserve 75 emergency 0
rate-limit
ingress-cancellation
partial-service fec-threshold 1
partial-service snr-threshold 0
no small-signal-compensation
logical-channel 0 description "Independencia-7"
logical-channel 0 prov-attr-mask 0xFFFF
logical-channel 0 channel-width 6400000
logical-channel 0 profile 64 secondary-profile 16,10
logical-channel 0 minislot 1
logical-channel 0 data-backoff automatic
logical-channel 0 ranging-backoff 2 8
logical-channel 0 pre-equalization 1440
no logical-channel 0 post-equalization
logical-channel 0 power-offset 0
logical-channel 0 ranging-priority 0x0
logical-channel 0 class-id 0x0
no logical-channel 0 shutdown
logical-channel 1 prov-attr-mask 0x0
logical-channel 1 channel-width 6400000
logical-channel 1 profile 3
logical-channel 1 minislot 1
logical-channel 1 data-backoff automatic
logical-channel 1 ranging-backoff 0 4
no logical-channel 1 pre-equalization
no logical-channel 1 post-equalization
logical-channel 1 power-offset 0
logical-channel 1 ranging-priority 0x0
logical-channel 1 class-id 0x0
logical-channel 1 shutdown
no shutdown
interface upstream 12/14.2
description "Independencia-7"
spectrum-rule 1
frequency 68200000
channel-width 6400000
power-level 0
no fast-carrier-offset
power-adjustment continue 2
power-adjustment threshold 1
voice-bw-reserve 75 emergency 0
rate-limit
ingress-cancellation
partial-service fec-threshold 1
partial-service snr-threshold 0
no small-signal-compensation
logical-channel 0 description "Independencia-7"
logical-channel 0 prov-attr-mask 0xFFFF
logical-channel 0 channel-width 6400000
logical-channel 0 profile 64 secondary-profile 16,10
logical-channel 0 minislot 1
logical-channel 0 data-backoff automatic
logical-channel 0 ranging-backoff 2 8
logical-channel 0 pre-equalization 1440
no logical-channel 0 post-equalization
logical-channel 0 power-offset 0
logical-channel 0 ranging-priority 0x0
logical-channel 0 class-id 0x0
no logical-channel 0 shutdown
logical-channel 1 prov-attr-mask 0x0
logical-channel 1 channel-width 6400000
logical-channel 1 profile 3
logical-channel 1 minislot 1
logical-channel 1 data-backoff automatic
logical-channel 1 ranging-backoff 0 4
no logical-channel 1 pre-equalization
no logical-channel 1 post-equalization
logical-channel 1 power-offset 0
logical-channel 1 ranging-priority 0x0
logical-channel 1 class-id 0x0
logical-channel 1 shutdown
no shutdown
interface upstream 12/14.3
description "Independencia-7"
spectrum-rule 1
frequency 61800000
channel-width 6400000
power-level 0
no fast-carrier-offset
power-adjustment continue 2
power-adjustment threshold 1
voice-bw-reserve 75 emergency 0
rate-limit
ingress-cancellation
partial-service fec-threshold 1
partial-service snr-threshold 0
no small-signal-compensation
logical-channel 0 description "Independencia-7"
logical-channel 0 prov-attr-mask 0xFFFF
logical-channel 0 channel-width 6400000
logical-channel 0 profile 64 secondary-profile 16,10
logical-channel 0 minislot 1
logical-channel 0 data-backoff automatic
logical-channel 0 ranging-backoff 2 8
logical-channel 0 pre-equalization 1440
no logical-channel 0 post-equalization
logical-channel 0 power-offset 0
logical-channel 0 ranging-priority 0x0
logical-channel 0 class-id 0x0
no logical-channel 0 shutdown
logical-channel 1 prov-attr-mask 0x0
logical-channel 1 channel-width 6400000
logical-channel 1 profile 3
logical-channel 1 minislot 1
logical-channel 1 data-backoff automatic
logical-channel 1 ranging-backoff 0 4
no logical-channel 1 pre-equalization
no logical-channel 1 post-equalization
logical-channel 1 power-offset 0
logical-channel 1 ranging-priority 0x0
logical-channel 1 class-id 0x0
logical-channel 1 shutdown
no shutdown
interface upstream 12/14.4
description "Independencia-7"
spectrum-rule 1
frequency 40100000
channel-width 3200000
power-level 8
no fast-carrier-offset
power-adjustment continue 2
power-adjustment threshold 1
voice-bw-reserve 75 emergency 0
rate-limit
ingress-cancellation
partial-service fec-threshold 1
partial-service snr-threshold 0
no small-signal-compensation
logical-channel 0 description "Independencia-7"
logical-channel 0 prov-attr-mask 0x0
logical-channel 0 channel-width 3200000
logical-channel 0 profile 64 secondary-profile 16,10
logical-channel 0 minislot 2
logical-channel 0 data-backoff automatic
logical-channel 0 ranging-backoff 2 8
logical-channel 0 pre-equalization 1440
no logical-channel 0 post-equalization
logical-channel 0 power-offset 0
logical-channel 0 ranging-priority 0x0
logical-channel 0 class-id 0x0
no logical-channel 0 shutdown
logical-channel 1 prov-attr-mask 0x0
logical-channel 1 channel-width 3200000
logical-channel 1 profile 2
logical-channel 1 minislot 2
logical-channel 1 data-backoff automatic
logical-channel 1 ranging-backoff 0 4
no logical-channel 1 pre-equalization
no logical-channel 1 post-equalization
logical-channel 1 power-offset 0
logical-channel 1 ranging-priority 0x0
logical-channel 1 class-id 0x0
logical-channel 1 shutdown
no shutdown
interface upstream 12/14.5
description "Independencia-7"
spectrum-rule 1
frequency 36900000
channel-width 3200000
power-level 8
no fast-carrier-offset
power-adjustment continue 2
power-adjustment threshold 1
voice-bw-reserve 75 emergency 0
rate-limit
ingress-cancellation
partial-service fec-threshold 1
partial-service snr-threshold 0
no small-signal-compensation
logical-channel 0 description "Independencia-7"
logical-channel 0 prov-attr-mask 0x0
logical-channel 0 channel-width 3200000
logical-channel 0 profile 64 secondary-profile 16,10
logical-channel 0 minislot 2
logical-channel 0 data-backoff automatic
logical-channel 0 ranging-backoff 2 8
logical-channel 0 pre-equalization 1440
no logical-channel 0 post-equalization
logical-channel 0 power-offset 0
logical-channel 0 ranging-priority 0x0
logical-channel 0 class-id 0x0
no logical-channel 0 shutdown
logical-channel 1 prov-attr-mask 0x0
logical-channel 1 channel-width 3200000
logical-channel 1 profile 2
logical-channel 1 minislot 2
logical-channel 1 data-backoff automatic
logical-channel 1 ranging-backoff 0 4
no logical-channel 1 pre-equalization
no logical-channel 1 post-equalization
logical-channel 1 power-offset 0
logical-channel 1 ranging-priority 0x0
logical-channel 1 class-id 0x0
logical-channel 1 shutdown
no shutdown
interface upstream 12/14.6
description "Independencia-7"
frequency 33700000
channel-width 3200000
power-level 8
no fast-carrier-offset
power-adjustment continue 2
power-adjustment threshold 1
voice-bw-reserve 75 emergency 0
rate-limit
ingress-cancellation
partial-service fec-threshold 1
partial-service snr-threshold 0
no small-signal-compensation
logical-channel 0 description "Independencia-7"
logical-channel 0 prov-attr-mask 0x0
logical-channel 0 channel-width 3200000
logical-channel 0 profile 64 secondary-profile 16,10
logical-channel 0 minislot 2
logical-channel 0 data-backoff automatic
logical-channel 0 ranging-backoff 2 8
logical-channel 0 pre-equalization 1440
no logical-channel 0 post-equalization
logical-channel 0 power-offset 0
logical-channel 0 ranging-priority 0x0
logical-channel 0 class-id 0x0
no logical-channel 0 shutdown
logical-channel 1 prov-attr-mask 0x0
logical-channel 1 channel-width 3200000
logical-channel 1 profile 2
logical-channel 1 minislot 2
logical-channel 1 data-backoff automatic
logical-channel 1 ranging-backoff 0 4
no logical-channel 1 pre-equalization
no logical-channel 1 post-equalization
logical-channel 1 power-offset 0
logical-channel 1 ranging-priority 0x0
logical-channel 1 class-id 0x0
logical-channel 1 shutdown
no shutdown
interface upstream 12/14.7
description "Independencia-7"
frequency 30500000
channel-width 3200000
power-level 8
no fast-carrier-offset
power-adjustment continue 2
power-adjustment threshold 1
voice-bw-reserve 75 emergency 0
rate-limit
ingress-cancellation
partial-service fec-threshold 1
partial-service snr-threshold 0
no small-signal-compensation
logical-channel 0 description "Independencia-7"
logical-channel 0 prov-attr-mask 0x0
logical-channel 0 channel-width 3200000
logical-channel 0 profile 64 secondary-profile 16,10
logical-channel 0 minislot 2
logical-channel 0 data-backoff automatic
logical-channel 0 ranging-backoff 2 8
logical-channel 0 pre-equalization 1440
no logical-channel 0 post-equalization
logical-channel 0 power-offset 0
logical-channel 0 ranging-priority 0x0
logical-channel 0 class-id 0x0
no logical-channel 0 shutdown
logical-channel 1 prov-attr-mask 0x0
logical-channel 1 channel-width 3200000
logical-channel 1 profile 2
logical-channel 1 minislot 2
logical-channel 1 data-backoff automatic
logical-channel 1 ranging-backoff 0 4
no logical-channel 1 pre-equalization
no logical-channel 1 post-equalization
logical-channel 1 power-offset 0
logical-channel 1 ranging-priority 0x0
logical-channel 1 class-id 0x0
logical-channel 1 shutdown
no shutdown
I am attentive to your help
Is this in a production network or a lab (2m plant)?
If this is a lab or 6' (2m) plant that is strange indeed.
If this is a production network, first question is why do you have the power level set to 8 dB on the < 42 MHz channels? Typically this is set to 0 dB on upstream channels. Changing it to 8 forces the modem to adjust it power level 8 dB. A better way to accomplish this would be to adjust 8 dB of attenuation in the cabling between the US port and the return receiver. A good use case for this would be for the US channels > 42 MHz as they are a higher frequency they will attenuate faster you will likely (especially with longer cable runs) need to add attenuation to those channels to raise the SNR you should use a meter/spectrum analyzer to make all the haystacks the same size.
Also if this is a production network, you will need to sweep the plant out to 85 MHz as well, it is likely you have not used >42 MHz for docsis previously, it will need to have its tilt properly set in the Amps and any impairments corrected.
Hi
the test is in production red
The CMTS may support 85MHz, but does everything else in your plant support it ?
Nodes, amps, LE, end-of-line equalizers etc etc
Perhaps some gear is only 42MHz, resulting in roll-off / attenuation / group-delay for the higher frequencies.