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ZL30105 Datasheet(PDF) 34 Page - Zarlink Semiconductor Inc |
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ZL30105 Datasheet(HTML) 34 Page - Zarlink Semiconductor Inc |
34 / 50 page ![]() ZL30105 Data Sheet 34 Zarlink Semiconductor Inc. 5.5 Clock Redundancy System Architecture Carrier-Class Telecommunications Equipment deployed in today’s networks guarantee better than 99.999% operational availability (equivalent to less than 7 minutes of downtime per year). This high level of uninterrupted service is achieved by fully redundant architectures with hot swappable cards like an ECTF H.110 or a PICMG AdvancedTCA™ compliant system. Timing for these types of systems can be generated by the ZL30105 which supports primary/secondary master timing protection switching. The architecture shown in Figure 24 and Figure 25 is based on the ZL30105 being deployed on two separate timing cards; the primary master timing card and the secondary master timing card. In normal operation the primary master timing card receives synchronization from the network and provides timing for the whole system. The redundant secondary master timing card is phase locked to the backplane clock and frame pulse through its REF2 and REF2_SYNC inputs. These two designated inputs allow the secondary master timing card to track the primary master timing card clocks with minimal phase skew. When the primary master timing card fails unexpectedly (this failure is not related to reference failure) then all switch cards or line cards will detect this failure and they will switch to the timing supplied by the secondary master timing card. The secondary master timing card will be promoted to primary master and switch from using the REF2 and REF2_SYNC inputs to one of the REF0 or REF1 inputs. Figure 24 - Typical Clocking Architecture of an ECTF H.110 System ZL30105 REF2 REF0 Primary Master Timing Card REF1 MT90866 Backplane REF2_SYNC C8o F8o CT_C8_A CT_FRAME_A CT_C8_B CT_FRAME_B CT_NETREF_1 CT_NETREF_2 SEC_MSTR Master/Slave Control 0 ZL30105 REF2 REF0 Secondary Master Timing Card REF1 REF2_SYNC C8o F8o SEC_MSTR Master/Slave Control 1 H.110 DX MT90866 H.110 DX |