Features for Troubleshooting
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JUNOSg 3.0 G10 CMTS Hardware Guide
142
Flap List
The CMTS maintains a database of cable modems, along with various statistics for each cable
modem. When a cable modem exhibits behavior that matches pre-defined criteria—referred
to as a
flap
—an entry is added to a table called a
flap list
. Each flap list entry contains the
MAC address of the cable modem, along with additional modem statistics that can assist in
determining why the cable modem flapped. You can display the flap list by issuing the
show
cable modem flaps
command.
You can define global flap criteria or define flap criteria on an upstream interface basis. Flap
criteria defined for an upstream interface override those set at the global level. If a parameter
is not explicitly set, a flap is defined by its default value.
After an entry is added to the flap list for a cable modem, any subsequent flap for that cable
modem, whether defined explicitly or by default, updates that flap list entry with new
statistics (including a flap count). Examples of flaps include excessive initial ranging, missed
station maintenance opportunities, large upstream power adjustments, and an SNR dropping
below a threshold.
The flap list can be used to assist you with troubleshooting, locating CMTS and cable modem
configuration issues, and locating problems in the HFC plant without impacting throughput
and downstream performance, and without creating additional packet overhead throughout
the HFC network.
For more information about the flap list, see the
JUNOSg Software Configuration Guide:
Interfaces, Cable, Policy, and Routing and Routing Protocols
.
Use the Flap List for Troubleshooting
To display the flap list, issue the
show cable flap-list
command:
user@host>
show cable flap-list
MAC-Address Interface Us/Port IM SM PAdj FAdj SNR MER
CER LTime LEvnt Total FAdjAmnt SNRavg MERavg CERavg
00:20:40:BF:5B:C4 ca-0/2/1 2/1 0 0 1 0 0 0
0 Feb 18 12:04:21 PADJ FLAP 1 0 33 23 0
00:E0:6F:03:16:DB ca-0/2/0 9/0 0 0 13 0 0 0
0 Feb 18 12:04:28 PADJ FLAP 13 0 28 24 0
Table 45 on page 143 provides potential HFC plant issues associated with some of the flaps
and statistics displayed in the output fields. The quantification of the flap counts and statistics
is plant dependent, so general qualifications, such as
High
and
Low
, are provided.
Содержание G10 CMTS
Страница 8: ... JUNOSg 3 0 G10 CMTS Hardware Guide viii ...
Страница 18: ... JUNOSg 3 0 G10 CMTS Hardware Guide 2 ...
Страница 34: ...G10 CMTS Hardware Overview JUNOSg 3 0 G10 CMTS Hardware Guide 18 ...
Страница 46: ...DOCSIS Module JUNOSg 3 0 G10 CMTS Hardware Guide 30 Figure 12 DOCSIS Module Front Panel HotSwap ...
Страница 55: ... Hardware Component Overview Chassis Control Module 39 Figure 15 Chassis Control Module Front Panel Eth0 ...
Страница 72: ...Chassis Rear Modules JUNOSg 3 0 G10 CMTS Hardware Guide 56 Figure 21 Hard Disk Module Rear Panel C O M Eth ...
Страница 82: ... JUNOSg 3 0 G10 CMTS Hardware Guide 66 ...
Страница 112: ...Rack Mounting JUNOSg 3 0 G10 CMTS Hardware Guide 96 Figure 25 Air Flow Through Chassis ...
Страница 116: ...Rack Mounting JUNOSg 3 0 G10 CMTS Hardware Guide 100 Figure 29 Rack Fully Populated with Three G10 CMTS Chassis ...
Страница 118: ...Install Power Supplies JUNOSg 3 0 G10 CMTS Hardware Guide 102 Figure 30 Power Supply Installation 1 2 ...
Страница 138: ...Connect to Power Sources JUNOSg 3 0 G10 CMTS Hardware Guide 122 Figure 39 DC Power Transition Module ...
Страница 148: ... JUNOSg 3 0 G10 CMTS Hardware Guide 132 ...
Страница 156: ...Upstream RF Measurement JUNOSg 3 0 G10 CMTS Hardware Guide 140 ...
Страница 188: ... JUNOSg 3 0 G10 CMTS Hardware Guide 172 ...
Страница 196: ...Radio Frequency RF Specifications JUNOSg 3 0 G10 CMTS Hardware Guide 180 ...
Страница 202: ...EIA Channel Plans JUNOSg 3 0 G10 CMTS Hardware Guide 186 ...
Страница 203: ... 187 Part 5 Index Index on page 189 ...
Страница 204: ... JUNOSg 3 0 G10 CMTS Hardware Guide 188 ...
Страница 209: ... Index 193 Index V ventilation 69 89 95 101 124 161 162 167 video servers 7 voltage power supply 27 ...
Страница 210: ... Index JUNOSg 3 0 G10 CMTS Hardware Guide 194 ...