user manual

Configuring Headend Broadband Access Router Features
Configuring the Upstream Cable Interface
MC-559
Cisco IOS Multiservice Applications Configuration Guide
To activate the upstream ports, use the following commands beginning in global configuration mode:
Verifying the Upstream Ports
To verify whether the upstream ports are activated or deactivated, enter the show interface cable
command for the upstream port that you have just configured:
router# show interface cable 6/0
Cable6/0 is up, line protocol is up
Hardware is BCM3210 FPGA, address is 00e0.1e5f.7a60 (bia 00e0.1e5f.7a60)
Internet address is 1.1.1.3/24
MTU 1500 bytes, BW 27000 Kbit, DLY 1000 usec, rely 255/255, load 1/255
Encapsulation, loopback not set, keepalive not set
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:25, output 00:00:00, output hang never
Last clearing of “show interface” counters never
Queueing strategy: fifo
Output queue 0/40, 0 drops; input queue 0/75, 0 drops
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.
Setting Upstream Backoff Values
The DOCSIS-specified method of contention resolution for cable modems wishing to transmit data or
requests on the upstream channel is a truncated binary exponential backoff, with the initial backoff
window and the maximum backoff window controlled by the CMTS. The Cisco uBR7200 series router
specifies backoff window values for both data and initial ranging, and sends these values downstream as
part of the Bandwidth Allocation Map (MAP) MAC message. The values are configurable on the
Cisco uBR7200 series and are power-of-two values. For example, a value of 4 indicates a window from
0 to 15; a value of 10 indicates a window from 0 to 1023.
Command Purpose
Step 1
CMTS01(config)# interface cable slot/port
Specifies a cable interface and enters cable interface
configuration mode.
Step 2
CMTS01(config-if)# no cable upstream usport shutdown
Enables upstream data traffic.