Troubleshooting guide

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Cisco Broadband Local Integrated Services Solution Troubleshooting Guide
OL-5169-01
Chapter 7 Troubleshooting the CMTS
Troubleshooting the Cisco uBR7246VXR
The following command displays output for the downstream cable interface of slot 6 on port 0:
router# show interface cable 6/0 downstream
Cable6/0: Downstream is up
111947771 packets output, 1579682655 bytes, 0 discarded
0 output errors
Upstream and Downstream Traffic Shaping
The Cisco uBR7200 series universal broadband router supports buffering both upstream and downstream
grants to cable modems that are exceeding their allocated bandwidth. This strategy helps to avoid the
TCP timeouts and the retransmission of the associated packets which would further degrade overall
throughput.
The cable downstream port number rate-limit token-bucket shaping and cable upstream port number
rate-limit token-bucket shaping commands configure the Cisco uBR7200 series universal broadband
router to perform rate shaping by buffering the grants for rate-exceeded modems.
Init Mtn IEs The counter of Initial Maintenance IEs; that is,
counters for each type of upstream slot scheduled
in the MAPs for this upstream channel.
For example, “Init Mtn IEs 800” means that the
MAC scheduler has added 800 initial
maintenance information elements (slots) at the
time the show command was issued.
Stn Mtn IEs Number of station maintenance (ranging poll)
IEs.
Long Grant IEs Number of long grant IEs.
Short Grant IEs Number of short grant IEs.
Avg upstream channel utilization Indicates on average what percent of the upstream
channel bandwidth is being used.
Avg percent contention slots Indicates on average what percent of slots are in
contention state.
Avg percent initial ranging slots Indicates on average what percent of slots are in
initial ranging state.
Avg percent minislots lost on late MAPs Indicates on average what percent of slots are lost
because a MAP interrupt was too late.
Current minislot count (formerly: Last Minislot
Stamp (current_time_base))
Indicates the current minislot count at the CMTS.
FLAG indicates the timebase reference. This field
is used only by developers.
Scheduled minislot count (formerly: Last
Minislot Stamp (scheduler_time_base))
Indicates the furthest minislot count allocated at
the indicated time. FLAG indicates the timebase
reference. This field is used only by developers.
Table 7-8 Show Interface Cable Upstream Command Field Descriptions (continued)
Field Description