Cisco MC16E Dokumentacja

Cisco − Determining RF or Configuration Issues On the CMTS

Router#Note: This is showing a downstream receive SNR of 33.6 dB at the cable modem. Acceptance levels are >30dB for 64 QAM and > 35 dB for 256

Ranging Backoff automatic (Start 0, End 3) Ranging Insertion Interval 100 ms TX Backoff Start 0, TX Backoff End 4 Modulation Profile Group 1 Con

Waterfall curves. More complex modulation formats require a higher CNR (or C/N ratio) in order to maintainthe same BER.The upstream input power level

Range Load Reg Size=0x58 Request Load Reg Size=0x0E Minislot Size in number of Timebase Ticks is = 8 Minislot Size in Symbols = 128 Bandwidth Re

In practice, a margin of 6dB or more may be required forreliable operation.Use the show interface cable x/x upstream y command as shown below to check

Uncorrectable Error packets received through upstreaminterface that could not be correctedNoise and Upstream packets corrupted by linenoiseMicroreflec

Avg percent minislots lost onlate MapsAverage percent of slots lost because aMAP interrupt was too lateTotal channel bw reservedTotal amount of bandwi

The maximum rate that frequency hopping will occur (inseconds)Corr FECErrors The number of correctable forward error corrections (FEC)errors on this u

The flap list is an event detector, and there are three situations that causes an event to be counted. Below is adescription of these events that caus

Features, Differences, and IOS Support for Cable Modem Cards for Cisco uBR7200 Series• Technical Support − Cisco Systems• All contents are Copyright ©

Table of ContentsDetermining RF or Configuration Issues On the CMTS...1 I

Determining RF or Configuration Issues On theCMTSIntroductionBefore You Begin Conventions Prerequisites Components UsedRF Plant Troublesho

Components UsedThe information in this document is based on Cisco hardware uBR7246 VXR (NPE300) processor (revisionC) and Cisco IOS Software (UBR7200−

Comparing the Broadcom's upstream SNR estimate to what one would measure with a spectrum analyzer willoften yield quite different results. The Br

The downstream and upstream frequencies used• The noise measurements in dB. Make certain that they are correct and within the allowed limits. Atable o

+8 to +55 dBmV (16QAM)Input amplitude tomodem card(upstream) −16 to +26 dBmV,depending on symbol rate.−16 to +26 dBmV,depending on symbolrate.Signal a

Seasonal/diurnal signallevel variation8 dB 8 dBSignal level slope (50 to750 MHz)16 dB 16 dBMaximum analog videocarrier level at the CMinput, inclusive

interface Cable6/1 ip address 192.168.161.1 255.255.255.0 secondary ip address 10.1.61.1 255.255.255.0 no keepalive cable insertion−interval 100 cable