IF YOU SPECIFY AN THEN THE PROCEDURE WILL existing modulation profile ID change an existing modulation profile

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2 Use the following command to apply an existing modulation profile to an

upstream port. Do not enter a range of ports; the command must be repeated for each upstream port.

configure interface cable <slot>/<port> cable upstream <port.logical channel number> modulation-profile <modulation-profile id>

The C4 CMTS confirms the creation (or modification) of the modulation profile:

Modulation profile id set to n

Where: n = the number of the modulation-profile created or modified.

3 Verify the parameters of the new (modified) modulation profile: show cable modulation-profile <modulation-profile id>

The system response is similar to the following output: Modulation profile 1

Interval Chan Mod Pre Dif FEC FEC Scr Max Guar L Scr ---Atdma--- Prea ---Scdma--- Usage Type Type Len Enc CW amb Bur Time C amb Int Int mble TCM Int Sp Sub Code En Len Seed Siz Size S En Depth Block Type En Size En Cod --- 1 request tdma qpsk 64 F 0 16 338 2 8 F T - - - - - - - 3 initialRanging tdma qpsk 128 F 5 34 338 0 48 F T - - - - - - - 4 periodicRanging tdma qpsk 128 F 5 34 338 0 48 F T - - - - - - - 5 shortData tdma qpsk 72 F 6 75 338 12 8 T T - - - - - - - 6 longData tdma qpsk 80 F 8 220 338 0 8 T T - - - - - - - End of procedure

Procedure 10-6 How to Configure an Upstream (US) Channel

Perform this procedure for US channel 0 and repeat as necessary for channels 1–11 on this CAM. (Valid range for US channels = 0–11.) Some steps are optional. By not executing the optional steps, default settings are applied.

Valid Center Frequencies In the first step, set the center frequency of the upstream channel. The

range of valid center frequencies varies according to the channel width selected. The overall upstream bandwidth in North America is from 5–42 MHz. The first valid center frequency in Hertz is 5,000,000 plus ½ (channel width). The last valid frequency is 42,000,000 minus ½ (channel width).

The 2Dx12U CAM supports the extended Annex B upstream bandwidth used in Japan: from 5–55 MHz. It also supports Annex A (EuroDOCSIS), which is 5–65 MHz. These are the overall upstream range of frequencies. To calculate valid center frequencies refer to Table 10-6, Range of Valid Center Frequencies for DOCSIS and EuroDOCSIS Upstream Channels, on page 10-35.

NOTE

The Command Line Interface (CLI) supplies meaningful error messages for some but not all invalid combinations of channel width and frequency. If the CLI has no error message to give, a generic SNMP-level message is displayed. See Table 10-6.

1 (Required) Set the center frequency of the US port in Hertz (default =

12000000):

configure interface cable <slot>/<port> cable upstream <port> frequency <5100000-64900000>

Where 5100000 to 41900000 is the range of valid center frequencies in Hz in North America. Center frequencies range from 5100000 to 64900000. In Japan the range is from 5100000 to 54900000.

2 If desired, set US channel width in Hertz (default = 3200000):

configure interface cable <slot>/<port> cable upstream <port> channel-width {200000 | 400000 | 800000 | 1600000 | 3200000 | 6400000}

Where 200000, 400000, 800000, 1600000, 3200000, and 6400000 repre- sent the valid values for channel bandwidth in Hz.

Table 10-6: Range of Valid Center Frequencies for DOCSIS and EuroDOCSIS Upstream Channelsa

If channel width is…

Then first valid center frequency is…

And the last valid center frequency is…

DOCSIS (N. America) DOCSIS (Japan) EuroDOCSIS (Europe)

200000 5100000 41900000 54900000 64900000 400000 5200000 41800000 54800000 64800000 800000 5400000 41600000 54600000 64600000 1600000 5800000 41200000 54200000 64200000 3200000 6600000 40400000 53400000 63400000 6400000b 8800000 38800000 51800000 61800000

a. Overall upstream frequencies in DOCSIS range from 5–42 MHz; in Japan from 5–55 MHz; in EuroDOCSIS from 5–65 MHz. b. Only DOCSIS 2.0 channels can use the 6.4 MHz width.

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NOTE

If the channel type is set to SCDMA, then the channel width must be set to 1600000, 3200000, or 6400000 Hz.

Setting the Rx Power Levels The C4 CMTS is shipped with its receive power levels set to a default of 0 dBmV. This level may prove unsuitable for operation for a given cable plant. If, for example, the loss on a given node were so great that the CMs could not transmit a strong enough signal to reach the C4 CMTS at 0 dBmV, then you would want to lower the expected receive power level.

3 If desired, change the input Rx power to any level from -16 to 29 dBmV

(default = 0 dBmV). As shown in Table 10-7, the valid range varies according to the upstream bandwidth.

configure interface cable <slot>/<port> cable upstream 0 power-level <-16 to 29>

If the width of a channel is changed and the receive power level is no longer valid, the C4 CMTS automatically adjusts the receive power to the nearest valid value.

NOTE

Resetting the receive power level in a single step from minimum to maximum in a given power range may prevent CM range requests from being received. For example, if the US channel bandwidth is 3200 kHz and the power level is reset from -4 to 26 dBmV, then the CMs might not register. The C4 CMTS avoids this by resetting the power in one or more steps according to the max-power-adj parameter found in the C4 CMTS cable upstream provisioning file.

4 If desired, change the maximum power adjustment parameter using the

following command (range = 1–48; default = 24 units, which equals 6 dBmV):

configure interface cable <slot>/<port> cable upstream <port> max-power-adj <power adjustment>

Table 10-7: Rx Power Ranges for US Channel Widths

US Channel Width in kHz Valid Rx Power Range (dBmV)

200 -16 to 14 400 -13 to 17 800 -10 to 20 1600 -7 to 23 3200 -4 to 26 6400 -1 to 29

Where: power adjustment = Maximum size of the CMTS range response power adjustments in 1/4 dBmV units.

5 If desired, set the start and end values for databackoff parameter (default

= 2-8):

configure interface cable <slot>/<port> cable upstream <port> databackoff <0-16>-<0-16>

Where: the first <0-16> is the valid range for the start value the second <0-16> is the valid range for the end value. The start value must be less than or equal to the end value.

6 If desired, enable or disable equalizer coefficient for this port.

configure interface cable <slot>/<port> cable upstream <port> pre-eq-enable <true|false>

Where: true = enabled and false = disabled.

7 If desired, select modulation profile ID (default = 1 or 2):

configure interface cable <slot>/<port> cable upstream <port> modulation-profile <profile id>

Where: <profile ID> = the modulation profile numeric identifier

8 If desired, set US power levels (default = 0):

configure interface cable <slot>/<port> cable upstream <port> power-level <power level in dBmV>

9 If desired, set the start and end values for range backoff parameter

(default = 2-7):

You must enter the start and end values separated by a dash.

configure interface cable <slot>/<port> cable upstream <port> rangebackoff <0-16>-<0-16>

Where: the first <0-16> is the valid range for the start value the second <0-16> is the valid range for the end value. the start value must be less than or equal to the end value.

10 If desired, put US port in service:

configure interface cable <slot>/<port> cable upstream <port> no shutdown

CAC Overload Thresholds The following step allows you to change upstream Connection Admission

Control (CAC) thresholds. The immediate effects of these thresholds are listed in Table 10-8. CAC thresholds affect all cable groups and persist even

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if no cable groups are configured. CAC thresholds can be used by Upstream Load Balancing, Packet Cable, and other features to prevent overallocation of bandwidth.

CAUTION

Changing CAC threshold settings will affect the performance of all cable groups and can have an impact on Upstream Load Balancing, Packet Cable, and any other features configured to use these settings.

11 If desired, change the overload threshold levels:

configure interface cable <slot>/<port> cable upstream <port> level{1|2|3}-threshold <percent>

12 If desired, modify some or all of the following parameters for this US

channel:

• map-size <size> (default = 4)

• mini-slot-size <number of 6.25 microsecond ticks> (default = 4) • threshold-power-offset <threshold value> (default = 24).

configure interface cable <slot>/<port> cable upstream [map-size <size in 800 microsecond ticks> ]

[mini-slot-size <number of 6.25 microsecond ticks>] [threshold-power offset <threshold-power-offset>] 13 Repeat this procedure as needed for the remaining US ports, 1–11, on this

CAM.

End of procedure

Table 10-8: Overload Threshold Defaults and their Effects

Threshold Default Value As soon as min. reserved bandwidth exceeds this levelEffect Level 1 80% a log message is generated.

Level 2 95% a log message is generated.