Specifications

In practice, a margin of 6dB or more may be required for
reliable operation.
Use the show interface cable x/x upstream y command as shown below to check for noise within the RF
plant. If the uncorrectable errors, noise, and microreflection counters are high and increasing quickly, then this
typically indicates there is noise present within the RF plant. (Please see the table below for a further
information on this output.)
VXR# show interfaces cable 6/1 upstream 0
Cable6/1: Upstream 0 is up
Received 22 broadcasts, 0 multicasts, 247822 unicasts
0 discards, 1 errors, 0 unknown protocol
247844 packets input, 1 uncorrectable
0 noise, 0 microreflections
Total Modems On This Upstream Channel : 1 (1 active)
Default MAC scheduler
Queue[Rng Polls] 0/64, fifo queueing, 0 drops
Queue[Cont Mslots] 0/52, FIFO queueing, 0 drops
Queue[CIR Grants] 0/64, fair queueing, 0 drops
Queue[BE Grants] 0/64, fair queueing, 0 drops
Queue[Grant Shpr] 0/64, calendar queueing, 0 drops
Reserved slot table currently has 0 CBR entries
Req IEs 360815362, Req/Data IEs 0
Init Mtn IEs 3060187, Stn Mtn IEs 244636
Long Grant IEs 7, Short Grant IEs 1609
Avg upstream channel utilization : 0%
Avg percent contention slots : 95%
Avg percent initial ranging slots : 2%
Avg percent minislots lost on late MAPs : 0%
Total channel bw reserved 0 bps
CIR admission control not enforced
Admission requests rejected 0
Current minislot count : 40084 Flag: 0
Scheduled minislot count : 54974 Flag: 0
VXR#
Received broadcasts Broadcast packets received through this
upstream interface
multicasts Multicast packets received through this
upstream interface
Unicasts Unicast packets received through this
interface
Discards
Packets discarded by this interface
Errors Sum of all errors that prevented upstream
transmission of packets
Unknown
Packets received that were generated
using a protocol unknown to the Cisco
uBR7246 Noise Upstream packets
corrupted by line noise
Packets input Packets received through upstream
interface free from errors
Corrected Error packets received through upstream
interface that were corrected
Cisco − Determining RF or Configuration Issues On the CMTS