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Cisco Broadband Cable Command Reference Guide
OL-1581-07
Chapter 6 Cable CPE Commands
show interfaces cable-modem
DS MAC Message Overruns: 0
DS Data Overruns : 0
Received MAPs : 254339485
Received Syncs : 53059555
Message CRC failures : 0
Header CRC failures : 1394
Data PDUs : 5853
DS MAC messages : 307861745
Valid Headers : 307869065
Sync losses : 0
Pulse losses : 1
BW request failures : 6
Router#
Table 6-32
describes the counters shown in this display.
Table 6-32 Counters Shown in show interfaces cable-modem counters Display
Field
Description
Ranging requests sent
Number of ranging requests sent by the router to the CMTS.
Downstream FIFO full
Number of times the downstream input first-in first-out (FIFO) buffer
became full on the router.
Re-requests
Number of times a bandwidth request generated by the router was not
responded to by the CMTS.
DS MAC Message
Overruns
Number of times the DMA controller had a downstream MAC message
and there were no free MAC message buffer descriptors to accept the
message.
DS Data Overruns
Number of times the DMA controller had downstream data and there were
no free data PDU buffer descriptors to accept the data.
Received MAPs
Number of times a MAP message passed all filtering requirements and
was received by the router.
Received Syncs
Number of times a time-stamp message was received by the router.
Message CRC failures
Number of times a MAC message failed a cyclic redundancy check
(CRC).
Header CRC failures
Number of times a MAC header failed its 16-bit CRC check. The MAC
header CRC is a 16-bit Header Check Sequence (HCS) field that ensures
the integrity of the MAC header even in a collision environment.
Data PDUs
Total number of data PDUs (protocol data units) of all types received by
the router.
DS MAC messages
Number of MAC messages received by the router.
Valid Headers
Number of valid headers received by the router, including PDU headers,
MAC headers, and headers only.
Sync losses
Number of times the router lost timebase sync with the CMTS.
Pulse losses
Number of times the router did not receive expected timestamp messages
from the CMTS.
BW request failures
Number of times the router sent the maximum number of re-requests for
bandwidth allocation and the request was still not granted.
