Troubleshooting guide

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Cisco Broadband Local Integrated Services Solution Troubleshooting Guide
OL-5169-01
Chapter 1 Solution Overview
Solution Components
Multimedia Terminal Adapters
Multimedia Terminal Adapters (MTA) are managed by service providers, but are physically located on
the customers premises. MTAs are combined with cable modems to form the primary CPE component
of the system that interfaces with the cable and provides the user with both Ethernet and telephone
access.
The MTA consists of a cable modem section and a telephone interface section.
• The cable modem section provides cable to Ethernet connectivity, using the DOCSIS specification
as a basis.
• The telephone interface section of the MTA provides a conversion from standard analog Plain Old
Telephone Service (POTS) telephone sets to digital (packetized) voice traffic.
A cable modem typically connects a cable wall hookup to a PC's 10 base-T Ethernet card. Utilizing an
always-on connection, cable modems transfer data across local cable TV lines, toggling between analog
and digital signals. With data transfer rates comparable to DSL, cable modems (1.5 - 2.5 Mbps) are
considerably faster than both dial-up modems (28.8 - 56 Kbps) and ISDN (128 Kbps).
Physical Interfaces
The following physical interfaces will usually be encountered on a typical MTA:
• Cable Interface—The cable interface conforms to the MCNS DOCSIS 1.0 and DOCSIS 1.0+
specifications.
• Ethernet Interface—The cable modem has a 10 BaseT interface on an RJ45 connector for data
access and features from two to four RJ11 interfaces supporting telephone, modem, and fax
communications.
• Telephone Interface—One or two channels of FXS (Foreign Exchange Station) POTS are provided
on RJ11 and RJ12 connectors.
Call Control, Signaling and Media Streams
In Cisco’s BLISS for Cable solution, MGCP is used as the signaling protocol between the MTA and the
Cisco BTS 10200 Call Agent. MGCP is used to set up the various parameters of connections, including
IP addresses, UDP ports, and so on. Audio streams are then passed directly between endpoints (typically
between an MTA and a CMTS).
In addition to setting up audio stream connections, MGCP allows the Call Agent to set up digit maps,
request events, and to apply signaling to the MTA. MGCP provides control while voice over IP transport
between MTAs andCMTSs is done by Real-Time Transport Protocol (RTP) for real-time applications.
DOCSIS QoS and Security Features
The MTA supports DOCSIS 1.0 and DOCSIS 1.0+ features, including baseline privacy (BPI) with some
additional QoS capabilities as defined for DOCSIS 1.1. Each MTA will have multiple Service IDs (SID)
to enable independent security and QoS for voice and data services.
Systems Management Interfaces
The MTA has been designed to be simple to install and configure. The MTA contains a DHCP client so
that, within the solution, IP addresses can be assigned dynamically via DHCP. Also returned from DHCP
as part of the DHCP-OFFER is the name of the MTA configuration file in the “boot file” name field.
The MTA also contains an SNMP agent that supports Cisco proprietary voice MIBs, as well as a
pre-released version of DOCSIS MIBs [MCNS10], allowing the MTA to be managed via SNMP.