Juniper Networks G10 CMTS manual User@host show cable modem summary total interface

Ideal HFC Plant Configuration Issues

•	8. You can compute the approximate upstream channel utilization by dividing the
•	measured bandwidth calculated in step 5 by the derated maximum bandwidth
•	calculated in step 7: (4,384,549 / 4,710,400)=93 percent. This represents a highly
•	utilized interface.
•
•	Congestion might be attributed to one or more of the following:
•
•	! An excessive number of cable modems are attached to a DOCSIS Module in the
•	return path of the HFC plant. Review your corporate guidelines to ensure you have
•	not exceeded the maximum number of cable modems per DOCSIS Module for the
•	modulation profiles being used. If necessary, install additional DOCSIS Modules.
•
•	! An excessive number of cable modems are assigned to the upstream interface in
•	which the cable modem transmits. Issue the show cable modem command as
•	follows to determine the number of cable modems within an upstream interface:
•
•	user@host> show cable modem summary total interface
•	cu-virtual-slot/docsis-slot/upstream-interface
•			---Cable Modem Operational States---
•
	Interface Us	CM	Dstry	Dclr	Rng	Rng	Rng	IP	Reg	Access
•
		Qty				Abort	Compl	Compl		Denied
•
	ca-0/2/0 0	5	0	0	0	5	0	0	0	0
•
	total	5	0	0	0	5	0	0	0	0
•
•	An excessive number of cable modems on an upstream interface can be addressed
•	by the following:
•
•	! Enable load balancing in the CMTS by including the load-balancestatement at
•		the [edit services cable upstream] hierarchy level. The CMTS attempts to
•		assign a cable modem to an upstream channel based on channel width and
•		utilization.
•
•	! Provision one or more additional upstream interfaces in the cable interface in
•		which the cable modem resides. The logical allocation of up to 16 upstream
•		interfaces to any of the upstream ports on a DOCSIS Module allows you to
•		provision interfaces without the need for physical node recombining.
•
•	! Increase the upstream channel width.
•
•	! The cable modem is transmitting using QPSK modulation. The all-digital processing of
•	the Broadband Cable Processor ASIC, along with its advanced noise cancellation and
•	equalization algorithms, might allow the cable modems on an upstream channel to
•	operate at 16QAM. To change the modulation of an upstream channel, assign a new
•	modulation profile to that channel.
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154 JUNOSg 3.0 G10 CMTS Hardware Guide