Cisco Systems uBR7200 Series Configure Spectrum Management (without the Cisco MC16S Cable Modem Card)

4-11
Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide
78-5897-01
Chapter4 Troubleshooting the System Managing Cable Modems on the HFC Network
To configure this, use the following command in cable interface configuration mode.
Using Cisco IOS Release 12.0(5)T1 or higher, the software supports:
•Generic calendar queuing routines
•New token bucket policing function
•Grant shaping application of the calendar queues
•Upstream rate shaping option to the token-bucket keyword
•A default state change from 1 second burst policing to token-bucket with shaping
Tips Upstream grant shaping is per CM (SID). Shaping can be enabled or disabled for the
token-bucket algorithm.
Note Before the introduction of this feature, the CMTS woulddrop bandwidth requests from a
CM it detected as exceeding its configured peak upstream rate. Such request dropping
affects the throughput performance of IP-based protocols such as FTP, TCP, and SMTP.
With this feature, the CMTS can shape (buffer) the grants for a CM that is exceeding its
upstream rate, rather than dropping the bandwidth requests.
CMTS01# show interface c3/0 sid 1 counters
Sid Inpackets Inoctets Outpackets Outoctets Ratelimit Ratelimit
BWReqDrop DSPktDrop
1 67859 99158800 67570 98734862 2579 0
Configure Spectrum Management (without the Cisco MC16S Cable
Modem Card)
Blind Strategies and Time Scheduled Combined
The Cisco uBR7200 series software supports combined blind and time scheduled spectrum
management using Cisco IOS Release 12.0(5)T1 images or higher:
•Using blind spectrum management, the number of lost station management messages exceedinga
configured threshold (default = 10) initiates an upstream channel frequency reassignment. The
Cisco uBR7200 series moves all cable modems on the upstream port by sending UCD messages
that contain the nextfrequency and input power level defined in the spectrum management group.
The frequency change occurs rapidly without data loss and minimal latency.
Table4-12 Instructions to Configure Upstream Shaping
Command Purpose
CMTS01(config-if)# [no] cable upstream <n1> rate-limit
[token-bucket] Enables or disables DOCSIS rate limiting or
shapingon an upstream channel. <n1> depends on
the number of upstream channels on the specific
cable modem card.