Chapter 4 Troubleshooting the System
Troubleshooting Using Cable Flap Lists
Table
Statistic | Description |
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MAC ID | This is the | ||
| the cable modem manufacturer, followed by six digits indicating a unique host address. Each | ||
| cable modem's MAC address is unique. | ||
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Cable IF | This is the physical upstream interface on the Cisco uBR7200. It denotes the cable modem card | ||
| slot number, the downstream port number on the RF line card and the upstream port number on | ||
| the same cable modem card. The flap list data can be sorted based on the upstream port number | ||
| which is useful when isolating reverse path problems unique to certain combining groups. | ||
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Insertions | Link insertion is the process whereby a modem performs an initial maintenance procedure to | ||
| establish link with the CMTS. The Ins column is the flapping modem’s insertion count and | ||
| indicates the number of times the RF link was abnormally | ||
| detected when the time between link | ||
| parameter. |
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| Normal modem activity follows the sequence below. | ||
| • The initial link insertion is followed by a keepalive loop between the CMTS and cable | ||
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| modem and is called station maintenance. | |
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| • | Initial maintenance | |
| • | Station maintenance | |
| • |
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| When the link is broken, initial maintenance is repeated to | ||
| Initial maintenance | @ Time T1 | |
| Station maintenance | ||
| Init maintenance | @ Time T2 | |
| The Ins and Flap counters in the flap list are incremented whenever T2 – T1 < N where N is the | ||
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| parameter is TBD seconds. | ||
| A high Ins number indicates: | ||
| • Intermittent downstream sync loss | ||
| • DHCP or modem registration problems | ||
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Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide
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