user manual

Configuring Headend Broadband Access Router Features
Configuring the Upstream Cable Interface
MC-553
Cisco IOS Multiservice Applications Configuration Guide
Activating Upstream Differential Encoding
To enable differential encoding on upstream traffic to a specified cable interface, use the following
command in cable interface configuration mode:
Upstream differential encoding is disabled by default.
Verifying Upstream Differential Encoding
To verify whether or not upstream differential encoding is activated, enter the show running-config
command and look for the cable interface configuration information. If upstream differential encoding
is enabled, a differential encoding entry will be displayed in the show running-config output. If
upstream differential encoding is disabled, no differential encoding entry will be displayed in the output.
Troubleshooting Tips
To troubleshoot the configuration, perform the following tasks:
• Make sure the cable connections are not loose or disconnected.
• Make sure the Cisco cable modem card is firmly seated in its chassis slot and the captive installation
screws are tight.
• Make sure you entered the correct slot and port numbers when you typed the command.
• Make sure you entered the correct upstream port number:
– On the MC16C cable modem card, this can be u0 to u5.
– On the MC14C cable modem card, this can be u0 to u3.
– On the MC12C cable modem card, this can be u0 or u1.
– On the MC11C cable modem card, this can be u0 only.
Activating Upstream Rate Limiting
Upstream rate limiting allows upstream bandwidth requests from rate-exceeding cable modems to be
buffered without incurring TCP-related timeouts and retransmits. The CMTS can thus enforce the peak
upstream rate for each cable modem without degrading overall TCP performance for the subscriber CPE
devices. Upstream grant shaping is per cable modem (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.
Command Purpose
CMTS01(config-if)# cable upstream usport
differential-encoding
Enables differential encoding.