Setting Upstream Rate Limiting And Traffic Shaping - Cisco uBR10012 Software Configuration Manual

Chapter 3 Configuring Cable Interface Features for the Cisco uBR10012 Router
Perform these steps if you are having difficulty with verification:
Ensure that the cable connections are not loose or disconnected.
Step 1
Ensure that the cable interface line card is firmly seated in its chassis slot.
Step 2
Step 3 Ensure that the captive installation screws are tight.
Verify that you have entered the correct slot and port numbers.
Step 4
Verify that you selected a valid frequency for your router.
Step 5

Setting Upstream Rate Limiting and Traffic Shaping

Upstream traffic shaping, available on the DOCSIS upstream channel, delays the scheduling of the
upstream packet, which in turn causes the packet to be buffered on the cable customer premises
equipment (CPE) device, instead of being dropped. This allows the user's TCP/IP stack to pace the
application traffic appropriately and approach throughput commensurate with the subscriber's defined
quality of service (QoS) levels.
The CMs are buffered without incurring TCP-related timeouts and retransmits. This enables the CMTS
to enforce the peak upstream rate for each CM, without degrading overall TCP performance for the
subscriber CPEs. Upstream grant shaping is per cable interface (per service ID (SID)).
Token-bucket policing with shaping is the per-upstream default rate-limiting setting at the CMTS.
Shaping can be enabled or disabled for the token-bucket algorithm.
To enable upstream traffic shaping for an upstream port on a Cisco cable interface line card, use one of
the following commands in cable interface configuration mode.
Command
Step 1
Router(config-if)# cable upstream usport
rate-limit
Router(config-if)# cable upstream usport
rate-limit token-bucket
Router(config-if)# cable upstream usport
rate-limit token-bucket shaping
Step 2
Router(config-if)# ^Z
Router#
To disable upstream traffic shaping for an upstream port, enter the following command in cable interface
configuration mode:
Router(config-if)# no cable upstream usport rate-limit
The software supports:
•
•
•
OL-1520-05
Generic calendar queuing routines
New token-bucket policing function
Grant shaping application of the calendar queues
Purpose
Enables traffic shaping for the specified upstream cable interface.
Enables traffic shaping for the upstream cable interface employing the
token-bucket policing algorithm. With this command the
Cisco uBR10000 series CMTS automatically drops packets in
violation of allowable upstream bandwidth.
Default. Enables traffic shaping for the upstream cable interface
employing the token-bucket policing algorithm with traffic shaping.
Exits back to the EXEC mode so that you can verify upstream traffic
shaping.
Cisco uBR10012 Universal Broadband Router Software Configuration Guide
Configuring the Upstream Cable Interface
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