Troubleshooting guide

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Cisco Broadband Local Integrated Services Solution Troubleshooting Guide
OL-5169-01
Chapter 1 Solution Overview
Solution Components
Cable Aggregation Components
The cable aggregation components of the network architecture for the BLISS for Cable 1.5 solution are
usually located at the HFC headend at the service provider’s POP or IP Central Office (IPCO).
HFC Headend
The headend is where all downstream signals originate and where all upstream signals terminate.
Figure 1-4 shows the headend components included in the BLISS for Cable solution, which are
described in the following sections.
Figure 1-4 Headend Architecture
The viability and the quality of VoIP on the HFC network is dependent on how the network is designed
and configured to handle the traffic to and from an ever-increasing number of residential MTAs. The
Cisco white paper Multimedia Traffic Engineering for HFC Networks by John J. Chapman, which is
available at http://www.cisco.com/warp/public/cc/so/cuso/sp/hfcn_wp.pdf,
describes many sizing and
scaling issues. In his white paper, Mr. Chapman provides a series of formulas for calculating minimum
and maximum loads, combined with practical advice on managing sizing and scaling issues.
Headend Components
The following physical devices/interfaces are usually located at the headend on an HFC cable network:
• Cable Modem Termination System (CMTS)—Connectivity to the service provider (SP) for PSTN
access is through a Cable Modem Termination System (CMTS) as defined in the DOCSIS 1.1
specification. CMTSs are managed by the service providers and are physically located at the cable
headend. All of the traffic from the cable portion of the network is aggregated on the CMTS. The
CMTS forwards IP data to/from the HFC infrastructure using the DOCSIS standard..
Cable Modem Termination Systems (CMTS) in the Cisco BLISS for Cable solution include:
– Cisco uBR7246VXR CMTS
– Cisco uBR10012 CMTS
transmitter
receiver
transmitter
receiver
transmitter
receiver
combiner
combiner
splitter
splitter
combiner
splitter
non-DOCSIS
upstream services
To fiber nodes
Video
CMTS/ER
(uBR7246vxr)
High-speed router
(GSR12000)
55653