Juniper ACX2000 Configuration Guide

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Configuring priority is optional. When not specified, gps has a higher default priority
than bits, and bits has a higher default priority than Gigabit Ethernet, 10-Gigabit Ethernet,
and T1 or E1 clock, which have the lowest default priority.
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When QL is enabled, the received QL must be equal to or better than the configured
QL for that particular source or else that source will not be considered for clock
selection. This is so that a downstream client is guaranteed clock quality of a certain
level (that “certain level” being the configured QL).
During clock selection:
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The active source with the highest QL is selected.
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If QL is the same for two or more sources, then the source with the highest priority is
selected.
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If two or more sources have the same QL and priority, then the currently active source,
if any, among these sources is selected.
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If two or more sources have the same QL and priority, and none of these is currently
active, then any one of these may be selected.
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If selection-mode is configured quality, then the configured (or default) QL of the
selected clock source is used for transmitting ESMC. If selection-mode is received
quality, then the received QL of the selected clock source is used for ESMC transmit.
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In order to receive or transmit ESMC messages out of an interface, at least one logical
interface should be configured on that interface. If the interface is currently not
configured with a logical interface, you may do so using the set interfaces interface-name
unit 0 statement at the edit hierarchy level.
Related
Documentation
Configuring External Clock Synchronization for ACX Series Routers on page 228•
• Understanding Interfaces on ACX Series Universal Access Routers on page 94
Configuring External Clock Synchronization for ACX Series Routers
The ACX Series Universal Access Routers support external clock synchronization for
Synchronous Ethernet, T1 or E1 line timing sources, and external inputs. Configuring
external clock synchronization requires making clock selection, quality level (QL), and
priority considerations. The clock source selection algorithm is used to pick the two best
upstream clock sources from among all the various sources, based on system
configuration and execution criteria such as QL, priority, and hardware restrictions.
To configure external synchronization on the router, include the synchronization statement
at the [edit chassis] hierarchy level.
Setting the Ethernet equipment clock (EEC) network type
The network type options set the frequency of the configured clock. When bits is
configured with option-1 on the ACX router, the Synchronous Ethernet equipment is
optimized for 2048 Kbps, the speed of an E1 interface. When bits is configured with
Copyright © 2017, Juniper Networks, Inc.228
ACX Series Universal Access Router Configuration Guide

Juniper ACX2000 Specifications

General

Brand	Juniper
Model	ACX2000
Category	Network Router
Language	English