Specifying Upstream Minislot Size - Cisco 7246VXR - uBR Router Software Configuration Manual

Chapter 3 Configuring Cable Modem Interface Features
Software adjustments of 1 to 3 dB can be used to adjust for minor variations in measurement or setup
Note
and port-to-port calibration differences. These adjustments can significantly improve cable interface
performance, especially in marginal situations. Larger adjustments should be made in conjunction with
spectrum analyzer support at the headend or distribution hub.

Specifying Upstream Minislot Size

To specify the minislot size (in ticks) for specific upstream cable interfaces, use the following command
in cable interface configuration mode. Acceptable values are 2, 4, 8, 16, 32, 64, and 128. The default is 8.
Router(config-if)# cable upstream usport minislot-size size
For additional information about channel width and minislot size, refer to the
(RF) FAQs
Verifying Upstream Minislot Size
To verify upstream minislot size, enter the show controllers cable command for the upstream port you
have just configured:
Router# show controllers cable5/0 u0
Cable5/0 Upstream 0 is up
Frequency 24.016 MHz, Channel Width 1.600 MHz, QPSK Symbol Rate 1.280 Msps
Spectrum Group is overridden
SNR 33.2560 dB
Nominal Input Power Level 0 dBmV, Tx Timing Offset 2288
Ranging Backoff automatic (Start 0, End 3)
Ranging Insertion Interval automatic (60 ms)
Tx Backoff Start 0, Tx Backoff End 4
Modulation Profile Group 1
part_id=0xFFFF, rev_id=0xFF, rev2_id=0xFF
nb_agc_thr=0x0000, nb_agc_nom=0x0000
Range Load Reg Size=0x58
Request Load Reg Size=0x0E
Minislot Size in number of Timebase Ticks is = 8
Minislot Size in Symbols = 64
Bandwidth Requests = 0xFE
Piggyback Requests = 0xD
Invalid BW Requests= 0x2
Minislots Requested= 0x2963
Minislots Granted
Minislot Size in Bytes = 16
Map Advance = 4000 usecs
UCD Count = 32964
DES Ctrl Reg#0 = C000C043, Reg#1 = 0
Perform these steps if you are having difficulty with verification:
Step 1 Ensure that the cable connections are not loose or disconnected.
Ensure that the cable interface line card is firmly seated in its chassis slot.
Step 2
Ensure that the captive installation screws are tight.
Step 3
Verify that you have entered the correct slot and port numbers.
Step 4
Verify that you selected a valid frequency for your router.
Step 5
OL-2239-03
on Cisco.com.
= 0x2963
Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide
Configuring the Upstream Cable Modem Interface
Cable Radio Frequency
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