- play_arrow Overview
- play_arrow Precision Time Protocol
- play_arrow Precision Time Protocol Overview
- play_arrow Precision Time Protocol Clocks
- PTP Boundary Clock Overview
- Example: Configure PTP Boundary Clock
- Example: Configure PTP Boundary Clock With Unicast Negotiation
- Configure PTP TimeTransmitter Clock
- Configure PTP TimeReceiver Clock
- Example: Configure Ordinary TimeReceiver Clock With Unicast-Negotiation
- Example: Configure Ordinary TimeReceiver Clock Without Unicast-Negotiation
- PTP Transparent Clocks
- Configure PTP Transparent Clock
- play_arrow Precision Time Protocol Profiles
- play_arrow PHY Timestamping
- play_arrow Precision Time Protocol over Ethernet
- PTP over Ethernet Overview
- Guidelines to Configure PTP over Ethernet
- Configure PTP Dynamic Ports for Ethernet Encapsulation
- Configure PTP Multicast TimeTransmitter and TimeReceiver Ports for Ethernet Encapsulation
- Example: Configure PTP over Ethernet for Multicast TimeTransmitter, TimeReceiver, and Dynamic Ports
- play_arrow Precision Time Protocol Additional Features
- Precision Time Protocol (PTP) over Link Aggregation Group (LAG)
- Precision Time Protocol (PTP) Trace Overview
- Line Card Redundancy for PTP
- Timing Defects and Event Management on Routing Platforms
- SNMP MIB for Timing on Routing Platforms
- PTP Passive Port Performance Monitoring on PTX10004 and PTX10008 Devices
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- play_arrow Global Navigation Satellite System (GNSS)
- play_arrow GPS Systems on Routing Platforms
- play_arrow Integrated GNSS on Routing Platforms
- play_arrow GNSS Configuration for Routers Using External GNSS Receiver
- play_arrow Assisted Partial Timing Support (APTS) on Routing Platforms
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- play_arrow Network Time Protocol
- play_arrow NTP Concepts
- play_arrow NTP Configuration Examples
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- play_arrow Synchronous Ethernet
- play_arrow Synchronous Ethernet Overview
- play_arrow Synchronous Ethernet on 10-Gigabit Ethernet MIC
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- play_arrow Hybrid Mode
- play_arrow Hybrid Mode Overview
- play_arrow Hybrid Mode and ESMC Quality-Level Mapping
- Configure Hybrid Mode and ESMC Quality-Level Mapping Overview
- Configure Hybrid Mode with Mapping of the PTP Clock Class to the ESMC Quality-Level
- Configure Hybrid Mode with a User-Defined Mapping of the PTP Clock Class to the ESMC Quality-Level
- Example: Configure Hybrid Mode and ESMC Quality-Level Mapping on ACX Series Router
- Example: Configure Hybrid Mode and ESMC Quality-Level Mapping on MX240 Router
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- play_arrow Configuration Statements and Operational Commands
- play_arrow Appendix
Clock Sources for PTX Series Routers
System clocking on PTX Series Packet Transport Routers is controlled by a Centralized Clock Generator (CCG). The CCG is capable of deriving a primary clock from a valid source and synchronizing all interfaces on the chassis to this primary clock. The CCG plugs into the rear of the chassis. A pair of CCGs installed in the chassis provide a redundant fallback option.
Synchronous Ethernet is configured on external primary and secondary interfaces that use building-integrated timing system (BITS), SDH Equipment Timing Source (SETS) timing sources, or an equivalent quality timing source such as GPS. On the PICs, the transmit clock of the interface is synchronized to a BITS or SETS timing source and is traceable to the timing source within the network.
Clock Sources for PTC Series Packet Transport Routers
PTX Series Packet Transport Routers can use an internal clock source or it can extract clocking from an external source.
Clock sources and specifications include:
The PTX Series Packet Transport Router clock is a Stratum 3E-compliant clock with Free Run +/- 4.6 ppm/20 years, Holdover +/- 0.01 ppm/24 hours, and Drift +/- 0.001 ppm/24 hours.
The internal clock is based on Freerun OCXO with +/- 10 ppb accuracy.
External clocking includes a choice of GPS-based clock recovery (5 MHz and 10 MHz) or BITS-T1/E1 Line synchronization (1.544 MHz and 2.048 MHz).
Synchronous Ethernet is supported based on the ITU-T G.8261, ITU-T G.8262, and ITU-T G8264 specifications with line timing from the 10-Gigabit Ethernet, 40-Gigabit Ethernet, or 100-Gigabit Ethernet interface.
Synchronous Ethernet is a key requirement for circuit (emulation) services and mobile radio access technologies. Synchronous Ethernet supports sourcing and transfer of frequency for synchronization purposes for both wireless and wireline services and is primarily used for mobile backhaul and converged transport.
In this example, the interface et-7/1/1 is configured as the primary clock source and GPS1 as the secondary clock source.
Note that you can specify the primary and secondary clock sources provided that the clock
source meets the necessary qualification as set by the clock algorithm. However, in the
absence of any user-selected clock source, the clock source with the best quality level is
selected by the clock algorithm in the router. Note that the user selection is honored even
when better quality level clock sources are available. You can select the clock source with
the request chassis synchronization switch clock-source
operational mode command.
The clock sources used as primary or secondary clock sources cannot originate from the same FPC.
For more information about clock source ports, see PTX3000 Clocking Port Cable Specifications and Pinouts, PTX5000 Centralized Clock Generator Description, and Connecting the PTX5000 to an External Clocking Device.
Getting Started to Configure Clock Synchronization on PTX Series Routers
System clocking on PTX Series Packet Transport Routers is controlled by a Centralized Clock Generator (CCG). The CCG is capable of deriving a primary clock from a valid source and synchronizing all interfaces on the chassis to this primary clock.
Task You Need to Perform | Where The Information Is Located |
|---|---|
Configure a clock source. | Synchronize Internal Stratum 3 Clock to External Clock Sources on PTX Series Routers |
Identify clock sources. | |
Change the clock source. | |
Configure the clock source mode to be revertive or non-revertive. | |
Verify the clock source is operational. |
