Juniper ACX2000 Configuration Guide

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PTP IPv4 with or without unicast negotiation
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PTPoE with or without stateful port
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By enabling the hybrid mode, the convergence time period is reduced and locking
happens quickly.
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You can configure the PTP Source as phase or time source for hybrid mode.
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You can configure Layer 2 rings for PTPoE with stateful ports and Synchronous Ethernet
with ESMC for Layer 2 ring topologies.
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When you enable hybrid mode, each node generates a phase error of or plus or minus
100 nanoseconds (without Phy Timestamping) or plus or minus 50 nanoseconds with
Phy timestamping feature. This phenomenon requires Frequency (SyncE/BITS/10
MHz) source and PTP source must be traceable to same PRC/PRS source.
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Fully redundant and resilient ring based configurations of up to 10 nodes are supported,
targeting the 1 microsecond phase requirement for a form of 4G known as Long-Term
Evolution-Time Division Duplex (LTE-TDD). A single node or link failure is
accommodated and all nodes are able to maintain phase accuracy to be +/- 1us
accurate to a common source.
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Hybrid mode for PTP IPv4 rings is not supported.
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Dynamic switchover from Hybrid to PTP mode is not supported in ACX routers.
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BITS T1 Clock with SSM is not supported. BITS E1 Clock with SSM is not supported.
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Hybrid Mode: Time Of Day (TOD) as Phase and Frequency as SyncE/BITS/10 MHz is
not supported. Simultaneous PTP IPv4 Ring and SyncE Hybrid Mode are not supported.
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Hybrid Mode with Phy Timestamping feature is not supported only on ACX500 series
routers.
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Dynamic Switchover from Hybrid to PTP Mode feature is not supported.
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Hybrid Feature on aggregated Ethernet (ae-) interfaces is not supported.
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When you configure hybrid mode, the following processes take place.
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The best of the configured PTP time sources is selected by the PTP Best Master
Clock Algoritm (BMCA).
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The best of configured chassis synchronization sources is selected by the
synchronization source selection algorithm.
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During the boot-up process, if valid sources are configured at the [edit chassis
synchronization] hierarchy level and chassis synchronization mode in free-running
mode, valid PTP source available case, system continues to operate in hybrid mode
( In this case, chassis synchronization is in free-run mode, whereas PTP is in locked
mode). When both primary and secondary frequency sources fail, system still works
under hybrid mode ( In this case, chassis synchronization is in hybrid mode and PTP
is in locked mode).
Related
Documentation
Hybrid Mode on ACX Series Routers Overview on page 288•
291Copyright © 2017, Juniper Networks, Inc.
Chapter 9: Configuring Timing and Synchronization

Juniper ACX2000 Specifications

General

Brand	Juniper
Model	ACX2000
Category	Network Router
Language	English