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13 — System timing and timing sources
2902 MainStreet Technical Practices 13-3
May 2002 90-2906-01
Procedure 13-2 ANS configuration summary
1 Enable ANS system timing on the node (see Procedure 13-3).
The STANDALONE and AUTO_SYNC softkeys only appear when all
synchronization sources have a status of disabled, undefined or unavailable. To
disable a timing source, see section 13.2.
2 Configure the timing sources that can provide timing for the network.
Timing source configuration parameters are described in section 13.2, and include
setting the class number, failure threshold and recovery method. See sections 13.3
to 13.6.
3 Define one CPSS channel per network link. See chapter 14 for information on
configuring CPSS channels. See section 13.7 for information on using links in an
ANS network.
4 Identify the CPSS links that are used for ANS and configure them as intra-sector
links (see section 13.7). These links carry timing and source routing information.
5 Identify the CPSS links that are not used for ANS or the links that define sector
boundaries, and configure them as inter-sector links (see section 13.7). These links
do not carry timing and source routing information.
Procedure 13-3 To set standalone or ANS system timing
CONFIG — SYNCH — AUTO_SYNC/STANDALONE*
* Default
13.2 Timing sources
Two timing sources are available to the 2902 MainStreet system—one from each
primary rate link. Timing source 1 is associated with the first primary rate link (P1)
and timing source 2 is associated with the second primary rate link (P2).
Only one timing source is active at any moment. The active timing source is referred
to as the current timing source. If the current source fails, the other source takes over.
Note —
When the method of synchronization is changed (standalone to
ANS, or ANS to standalone), timing sources are reset to their default
clock and recovery configurations (free-run and manual recovery).