Ace ACE-3105, Инструкция по установке и эксплуатации

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Installation and Operation Manual Appendix D Clock Modes
ACE-3105, ACE-3205 Ver. 5.2 System Clock Configuration D-3
D.2 Transmit Clock Configuration
The transmit (TX) clock source of each port is set to one of the following
configurations:
•
Internal – the transmit clock is provided by an internal oscillator, which is an
independent clock in the ACE-3105, ACE-3205 device. The accuracy of the
oscillator is +/-?? for DSL ports, and +/-50ppm for E1/T1 ports.
• Loopback – the transmit clock is retrieved from a specific port's incoming
(RX) data.
• System – the transmit clock is retrieved from the predefined master/fallback
clock.
The transmit clock source for an IMA group can be set to either Internal or
System. In APS mode, the transmit clock source configuration is always System.
D.3 System Clock Configuration
The system clock configuration is performed in accordance with the following
guidelines:
•
Two system clocks can be set – master and fallback. The master clock has a
default configuration, the fallback clock configuration is optional.
•
The master/fallback clock configuration can be derived from:
ƒ
The receive (RX) clock of a physical port's incoming data.
ƒ The receive (RX) clock of an IMA group's TRL (timing reference link).
ƒ
Incoming pseudowire from a packet-switched network (PSN), using a
dedicated clock recovery chip.
Configuration Notes
• If you disable a port from which the system clock is derived, or define the
system clock source (master or fallback) on a disabled port – the system
clock becomes unavailable (see 'Not Available' in
Clock Availability
).
•
An IMA group can be set as the system clock only if the group contains at
least one link. If an IMA group is defined as the system clock, the group
cannot be deleted and last link in that group cannot be removed.
•
In order to provide a ‘Group Clock’ for an IMA group in which the transmit
(TX) clock of all links is derived from the group's TRL:
ƒ The master clock should be set to the IMA group
ƒ The transmit clock of the IMA group should be set to System mode (for
explanation, see
Section D.2
,
Transmit Clock Configuration
).
ƒ All the remaining IMA groups may synchronize their transmit clock with
the system clock.
For details regarding the clock configuration procedures, refer to
Chapter 4
.