Alcatel-Lucent 1643 AMS Applications And Planning Manual page 263

SHDSL Overview
To be able to provide these synchronization services, the NT2M derives the
synchronization reference signal from the incoming SHDSL signal. This timing signal
can be traced back immediately to the LTU internal clock, since this clock is used to
generate the timing for the outgoing SHDSL links on the LTU. Possible SRUs in the
link will not change the traceability of the timing, since they always operate in
through-timed mode. In order for the NT2M to know the quality of the recovered clock
signal, the LTU sends the current quality level (SSM) to the NTU on a regular basis,
but certainly after each completed inventory phase and each time the Quality Level of
the internal clock changes in the LTU.
The NT2M will declare the recovered reference as insufficient, when the quality level
is SEC or worse.. So an 1643 Access Multiplexer AM / 1643 Access Multiplexer Small
AMS) clock that is free-running or in hold-over will not be accepted by the NT2M.
For the 2048 kHz output of the NT2M, the following requirements are important. It is
turned-off (squelched) as long as the SHDSL link is not functioning and when the level
of the reference is SEC or worse. Finally, it is possible to turn-off the timing output by
management command.
Performance Monitoring on LAN ports
On NT10ETH the following PM parameters are monitored: TxOctets, RxOctets and
RxDiscardedFrames. They are supported on both Ethernet ports and on the single
WAN port. The support includes threshold alarms for discarded frames.
NTU support
The following sections describe Ethernet NTU support features for SHDSL
configurations.
Enhanced NTU Ethernet PM: Ethernet traffic and error bin
The 1643 AM / 1643 AMS supports a 2 port Ethernet SHDSL modem as an NTU,
which is connected via 1 to 4 parallel TU12s over SHDSL mapped links. For increased
bandwidth, the Ethernet traffic is encapsulated in GFP-F and uses VC12-Xv virtual
concatenation with LCAS support.
The 1643 AM / 1643 AMS supports the following Enhanced NTU Ethernet ports PM
counters via the QD2-Lite extension.
• Ethernet Outgoing Number of Bytes (pCbS)
• Ethernet Incoming Number of Good Bytes (pCbR)
• Ethernet Outgoing Number of Frames (eONF)
• Ethernet Incoming Number of Good Frames (eINF)
• Ethernet Outgoing Number of Pause Frames transmitted (pPPS)
• Ethernet Number of Layer1 Link Down (eNLD)
• Ethernet Incoming Number of Frames with CRC Error (pPCR)
• Ethernet Incoming Number of Frames with oversize (eINFO)
• Ethernet Incoming Number of Frame with undersize (eINFU)
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365-312-801R7.2
Issue 3, May 2007
Alcatel-Lucent - Proprietary
See notice on first page
SHDSL features
12-17