Manuals+

Configuring Precision Time Protocol

Precision Time Protocol (PTP) is a protocol that defines a method to distribute time around a network. PTP support is based on the IEEE 1588-2008 standard. This document describes the concepts around this protocol and details the various configurations involved.

This document contains the following topics:

PTP Overview

The Precision Time Protocol (PTP), as defined in the IEEE 1588 standard, synchronizes real-time clocks of devices in a network with nanosecond accuracy. The clocks are organized into a master-slave hierarchy. PTP identifies the port connected to the device with the most precise clock, referred to as the master clock. All other devices on the network synchronize their clocks with the master and are referred to as members. Constantly exchanged timing messages ensure continued synchronization. PTP ensures that the best available clock is selected as the source of time (the grandmaster clock) for the network, and other clocks in the network are synchronized to the grandmaster.

Table 1: PTP Clocks

Network ElementDescription
Grandmaster (GM)A network device physically attached to the primary time source. All clocks are synchronized to the grandmaster clock.
Ordinary Clock (OC)An ordinary clock is an IEEE 1588 clock with a single PTP port that can operate in one of the following modes:
  • Master mode: Distributes timing information over the network to one or more slave clocks, allowing the slave to synchronize its clock to the master.
  • Slave mode: Synchronizes its clock to a master clock. Slave mode can be enabled on up to two interfaces simultaneously to connect to two different master clocks.
Boundary Clock (BC)The device participates in selecting the best master clock and can act as the master clock if no better clocks are detected. A boundary clock starts its own PTP session with a number of downstream slaves, mitigating network hops and packet delay variations between the Grand Master and Slave.
Transparent Clock (TC)A transparent clock is a device or switch that calculates the time required to forward traffic and updates the PTP time correction field to account for the delay, making the device transparent in terms of time calculations.

PTP consists of two parts:

  • The port State machine and Best Master Clock Algorithm (BMCA): Determines port states (passive, master, or slave) and selects the best master clock.
  • Delay-Request/Response mechanism and Peer-delay mechanism: Allows slave ports to calculate the difference between their own clock time and their master clock's time.

Note: Transparent Clock (TC) is not supported.

Frequency and Time Selection

The selection of the source to synchronize the device clock frequency is made by frequency synchronization and is outside the scope of PTP. The Announce, Sync, and Delay-request frequencies must be the same on the master and slave.

Delay-Response Mechanism

The Delay Request-response mechanism (defined in section 11.3 of IEEE Std 1588-2008) lets a slave port estimate the difference between its own clock-time and the clock-time of its master. The following options are supported:

  • One-step mechanism: The timestamp for a Sync message is sent in the Sync message itself.
  • Two-step mechanism: The timestamp for a Sync message is sent later in a Follow-up message.

When running a port in Slave state, a router can send Delay-request messages and handle incoming Sync, Follow-up, and Delay-response messages. The timeout periods for both Sync and Delay-response messages are individually configurable.

Hybrid Mode

The router allows the selection of separate sources for frequency and time-of-day (ToD). Frequency selection can be from any available source (e.g., BITS, GPS, SyncE, or IEEE 1588 PTP). ToD selection is between the source selected for frequency and PTP, if available (e.g., GPS or PTP). This is known as hybrid mode, where a physical frequency source (BITS or SyncE) provides frequency synchronization, while PTP provides ToD synchronization.

Frequency selection uses the algorithm described in ITU-T recommendation G.781. ToD selection is controlled using the time-of-day priority configuration, found under clock interface frequency synchronization configuration mode and global PTP configuration mode. Values from 1 to 254 are allowed, with lower numbers indicating higher priority.

The steps involved in Configuring PTP Hybrid Mode are described in a subsequent section.

Time of Day (ToD) Support

The router receives GPS ToD messages in a serial ASCII stream through the RS422 interface in any of the following formats:

  • NTP Type 4
  • Cisco
  • NMEA - GPZDA

Note: Refer to the support information in context of the current release and relevant Release Notes for more information on supported features and hardware.

Port States

The state machine indicates the behavior of each port. The possible states are:

StateDescription
INITPort is not ready to participate in PTP.
LISTENINGFirst state when a port becomes ready to participate in PTP. In this state, the port listens to PTP masters for a configurable period of time.
PRE-MASTERPort is ready to enter the MASTER state.
MASTERPort provides timestamps for any Slave or boundary clocks that are listening.
UNCALIBRATEDPort receives timestamps from a Master clock, but the router's clock is not yet synchronized to the Master.
SLAVEPort receives timestamps from a Master clock, and the router's clock is synchronized to the Master.
PASSIVEPort is aware of a better clock than the one it would advertise if it was in MASTER state and is not a Slave clock to that Master clock.

Restrictions for PTP

The following PTP restrictions apply to the Cisco NCS 5500 Series Router:

  • NCS55-RP does not support PTP.
  • SyncE is not supported on a 1GE copper SFP.
  • SyncE is not supported on 25 GE or 100 GE interfaces when they are used in 1G mode.
  • Sync2 interface is supported only if 10 MHz, 1 Pulse per Second (PPS), and time-of-day (ToD) ports are configured.
  • PTP is not supported with MACSec.
  • G.8273.2 Class-A performance is met if CFP2-DCO is configured on either Slave or Master port on the node.
  • Transparent Clock is not supported.

PTP Support Information

This table lists different types of support information related to PTP:

Transport MediaSupported Protocols
UDP over IPv4
  • Signaling
  • Announce
  • Sync
  • Follow-up
  • Delay-request
  • Delay-response
  • Management
Ethernet
  • Multicast: All packets are sent as multicast messages. Multicast is the only mode for PTP over ethernet profiles.
  • Unicast: This is the default mode. All packets are sent as unicast messages. Unicast is applicable only for PTP over IP profiles.

Timing Hardware Support Matrix

This section details the timing features supported across various Cisco hardware variants and Cisco IOS XR releases.

Table 2: Feature History Table

Feature NameRelease InformationFeature Description
PTP and SyncE on breakout ports on NCS55A1-48Q6H-S, NCS55A1-24Q6H-S, and NCS-5501-SE routers.Release 7.2.2IEEE-1588 PTP telecom Profiles 8275.1 and 8275.2, and Frequency Synchronization support is now extended to breakout ports on NCS55A1-48Q6H-S, NCS55A1-24Q6H-S, and NCS-5501-SE routers.

This table provides detailed information on timing features supported on the following hardware PIDs:

Hardware VariantFeaturesCisco IOS XR ReleaseComments
RP: NC55-RP-E
Line card: NC55-36X100G-A-SE		BITSRelease 6.3.2
SyncERelease 6.3.2SyncE is not supported on 25GE or 100GE interfaces, when they are used in 1G mode.
Dedicated 1588 Port (RP)Release 6.3.2
RP: NC55-RP-E
Line card: NC55-MOD-A-S		BITSRelease 6.5.1
SyncERelease 6.5.1SyncE is not supported on 100GE interfaces, when they are used in 1G mode.
Dedicated 1588 Port (RP)Release 6.5.1
G.8265.1Release 6.5.1
G.8275.1Release 6.5.1This profile is supported from Release 6.5.1 for IPv4.
G.8275.2Release 6.5.1Class B
GNSS ExternalRelease 6.5.1
G.8273.2Release 6.5.1Class B
NCS5501-SEBITSRelease 6.3.2
SyncERelease 6.3.2SyncE is not supported on 25GE or 100GE interfaces, when they are used in 1G mode. SyncE is supported on 10G from ports 8 to 15, but it is not supported on these ports in 1G mode.
G.8265.1Release 6.3.2
G.8275.1Release 6.3.2
G.8275.2Release 6.3.2
GNSS ExternalRelease 6.3.2
G.8273.2Release 6.5.1Class B
NCS-55A1-24HSyncERelease 6.5.2SyncE is not supported on 25GE or 100GE interfaces, when they are used in 1G mode.
G.8265.1Release 6.5.2
G.8275.1Release 6.5.2
G.8275.2Release 6.5.2
G.8273.2Release 6.5.2Class B
NCS55A2-MODSyncERelease 6.5.1SyncE is not supported on 25GE or 100GE interfaces, when they are used in 1G mode.
G.8265.1Release 6.5.1
G.8275.1Release 6.5.1
G.8275.2Release 6.5.1
G.8273.2Release 6.5.1Class B
NCS-55A1-24Q6H-SSyncERelease 6.6.25SyncE is not supported on 25GE or 100GE interfaces, when they are used in 1G mode.
G.8265.1Release 6.6.25
G.8275.1Release 6.6.25
G.8275.2Release 6.6.25
G.8273.2Release 6.6.25Class B
NCS-55A1-48Q6HSyncERelease 6.6.25SyncE is not supported on 25GE or 100GE interfaces, when they are used in 1G mode.
G.8265.1Release 6.6.25
G.8275.1Release 6.6.25
G.8275.2Release 6.6.25
G.8273.2Release 6.6.25Class B
NCS-55A1-36H-SE-SSyncERelease 7.0.1SyncE is not supported on 25GE or 100GE interfaces, when they are used in 1G mode.
G.8265.1Release 7.0.1
G.8275.1Release 7.0.1
G.8275.2Release 7.0.1
G.8273.2Release 7.0.1Class B
NCS-55A1-36H-SSyncERelease 7.0.1SyncE is not supported on 25GE or 100GE interfaces, when they are used in 1G mode.
G.8265.1Release 7.0.1
G.8275.1Release 7.0.1
G.8275.2Release 7.0.1
G.8273.2Release 7.0.1Class B
RP: NC55-RP-E with Line cards: NC55-MOD-A-S and NC55-32T16Q4H-ATBITSRelease 7.1.1
SyncERelease 7.1.1SyncE is not supported on 25GE or 100GE interfaces, when they are used in 1G mode.
G.8275.1Release 7.1.1For the Profile G.8275.1 NC55-32T16Q4H-AT supports only T-BC and does not support T-GM.
G.8273.2Release 7.1.1Class B
RP: NC55-RP2-E with Line cards: NC55-MOD-A-S and NC55-32T16Q4H-ATBITSRelease 7.1.1
SyncERelease 7.1.1SyncE is not supported on 25GE or 100GE interfaces, when they are used in 1G mode.
G.8275.1Release 7.1.1For the Profile G.8275.1 NC55-32T16Q4H-AT supports only T-BC and does not support T-GM.
G.8273.2Release 7.1.1Class B
RP: NC55-RP2-E with Line card: NC55-32T16Q4H-ATBITSRelease 7.1.1
SyncERelease 7.1.1SyncE is not supported on 25GE or 100GE interfaces, when they are used in 1G mode.
G.8275.1Release 7.1.1For the Profile G.8275.1 NC55-32T16Q4H-AT supports only T-BC and does not support T-GM.
G.8273.2Release 7.1.1Class C

Note: The line card NC55-32T16Q4H-AT displays the following behavior when configured for PTP:

  • The timing features are supported only on the 1G and 10G ports of the line cards.
  • When used in combination as listed in the table above, the line cards NC55-MOD-A-S and NC55-32T16Q4H-AT (with NC55-RP-E or NC55-RP2-E) support only 1G and 10G mode fixed ports as slave ports.
  • On the NC55-32T16Q4H-AT line card, only port numbers 1 to 31 in 1G and 10G mode support slave mode.
  • The NC55-RP2-E does not support PTP on the 1588 Port.
  • To configure Class C for the profile G.8273.2 when you use NC55-RP2-E with line card NC55-32T16Q4H-AT, follow the example below:
RP/0/RP0/CPU0:router# config
RP/0/RP0/CPU0:router(config)#frequency synchronization
RP/0/RP0/CPU0:router(config-freqsync)#timing-accuracy enhanced
RP/0/RP0/CPU0:router(config-freqsync)#commit

Note: Cisco NCS 5500 Series Routers support 64 PTP clients at 64 PPS sync packet rate.

Timing features are supported on the following MPAs:

  • NC55-MPA-2TH-S
  • NC55-MPA-1TH2H-S
  • NC55-MPA-1TH2H-HD-S
  • NC55-MPA-4H-S
  • NC55-MPA-4H-HD-S
  • NC55-MPA-12T-S

Breakout Timing Support

PTP Profiles 8275.1 and 8275.2 are supported on breakout ports on the following hardware PIDs:

Table 3: Breakout Timing Support Hardware Matrix

Hardware PIDClient PortServer Port
NCS-55A1-36H-S100G25G Breakout
NCS-55A1-36H-S100G10G Breakout
NCS-55A1-48Q6H10G25G Breakout
NCS-55A1-48Q6H100G25G Breakout
NCS-55A1-48T6H1G25G Breakout
NCS-55A1-48T6H10G25G Breakout
NCS-55A1-48T6H100G25G Breakout
NCS-5501-SE1G10G Breakout
NCS-5501-SE1G25G Breakout
NCS-5501-SE10G10G Breakout
NCS-5501-SE10G25G Breakout

Slow Tracking

Under normal configured conditions, any change in offset triggers an immediate reaction in the servo. With the Slow Tracking feature enabled, the servo corrects the phase offset based on the configured value. If the phase offset exceeds the acceptable range, the servo goes into Holdover state. In such a condition, the Slow Tracking feature becomes inactive, and the servo corrects itself to the latest offset and goes into Phase locked state. Slow Tracking becomes active again.

Note:

  • The supported slow tracking rate range is from 8-894 nanoseconds per second and must be in multiples of 8.
  • This feature is active only when the servo is in Phase locked mode.

Example configuration snippet:

Router:# config
ptp
clock
domain 24
profile g.8275.1 clock-type T-BC

ITU-T Telecom Profiles for PTP

Cisco IOS XR software supports ITU-T Telecom Profiles for PTP as defined in the ITU-T recommendations. A profile is a specific selection of PTP configuration options chosen to meet the requirements of a particular application.

PTP allows defining separate profiles to adapt for different scenarios. A telecom profile differs from the default behavior defined in the IEEE 1588-2008 standard. The key differences are mentioned in subsequent sections.

The following sections describe the ITU-T Telecom Profiles supported for PTP.

G.8265.1

G.8265.1 profile fulfills specific frequency-distribution requirements in telecom networks. Features of G.8265.1 profile are:

  • Clock advertisement: Specifies changes to values used in Announce messages for advertising PTP clocks. The clock class value advertises the quality level of the clock.
  • Clock Selection: Defines an alternate Best Master Clock Algorithm (BMCA) to select port states and clocks. It requires receiving Sync messages (and optionally, Delay-Response messages) to qualify a clock for selection.
  • Port State Decision: Ports are statically configured as Master or Slave, instead of using state machines to dynamically set port states.
  • Packet Rates: Higher packet rates than specified in IEEE 1588-2008 are used:
    • Sync/Follow-Up Packets: 128 packets-per-second to 16 seconds-per-packet.
    • Delay-Request/Delay-Response Packets: 128 packets-per-second to 16 seconds-per-packet.
    • Announce Packets: 8 packets-per-second to 64 packets-per-second.
  • Transport Mechanism: G.8265.1 profile only supports IPv4 PTP transport mechanism.
  • Mode: Supports transport of data packets only in unicast mode.
  • Clock Type: Only supports Ordinary Clock-type (a clock with one PTP port).
  • Domain Numbers: Network domain numbers range from 4 to 23. The default is 4.
  • Port Numbers: All PTP port numbers are one (1) as all clocks in this profile network are Ordinary Clocks.

G.8265.1 profile defines an alternate algorithm to select master clocks based on local priority and quality levels (QL). It also defines Packet Timing Signal Fail (PTSF) conditions to identify master clocks that do not qualify for selection:

  • PTSF-lossSync condition: Raised for master clocks not receiving a reliable stream of Sync and Delay-Resp messages.
  • PTSF-lossAnnounce condition: Raised for master clocks not receiving a reliable stream of Announce messages.
  • PTSF-unusable condition: Raised for master clocks receiving a reliable stream of Announce, Sync, and Delay-Resp messages, but not usable by slave clocks.

G.8275.1

G.8275.1 profile fulfills time-of-day and phase synchronization requirements in telecom networks with all participating devices. It provides better frequency stability for time-of-day and phase synchronization.

Features of G.8275.1 profile:

  • Synchronization Model: Adopts a hop-by-hop synchronization model. Each network device synchronizes its local clock to upstream devices and provides synchronization to downstream devices.
  • Clock Selection: Defines an alternate BMCA that selects a clock for synchronization and port state for local ports. Parameters include Clock Class, Clock Accuracy, Offset Scaled Log Variance, Priority 2, Clock Identity, Steps Removed, Port Identity, notSlave flag, and Local Priority.
  • Port State Decision: Port states are selected based on the alternate BMCA. A port can be configured to a master-only port state for multicast transport mode.
  • Packet Rates: Nominal packet rate for Announce packets is 8 packets-per-second, and for Sync/Follow-Up and Delay-Request/Delay-Response packets is 16 packets-per-second.
  • Transport Mechanism: Supports Ethernet PTP transport mechanism.
  • Mode: Supports transport of data packets only in multicast mode, based on forwardable or non-forwardable multicast MAC addresses.
  • Clock Type: Supports the following clock types:
    • Telecom Grandmaster (T-GM): Provides timing to other network devices; does not synchronize its local clock to other network devices.
    • Telecom Time Slave Clock (T-TSC): Synchronizes its local clock to another PTP clock but does not provide PTP synchronization to any other network devices.
    • Telecom Boundary Clock (T-BC): Synchronizes its local clock to a T-GM or an upstream T-BC and provides timing information to downstream T-BC or T-TSC clocks. If no higher-quality clocks are available, it may act as a grandmaster.
  • Domain Numbers: Network domain numbers range from 24 to 43. The default is 24.

The G.8275.1 supports:

  • T-GM: Provides timing to all devices; does not synchronize its local clock with any element other than the Primary Reference Time Clock (PRTC).
  • T-BC: Synchronizes its local clock to a T-GM or upstream T-BC, providing timing to downstream T-BCs or T-TSCs.
  • T-TSC: Synchronizes its local clock to another PTP clock (typically a T-BC) and does not provide synchronization to any other device.

Figure 1: A Sample G.8275.1 Topology

This topology illustrates a typical PTP network setup. It shows a flow from a Primary Reference Time Clock (PRTC) to a Telecom Grandmaster (T-GM), then to Telecom Boundary Clocks (T-BC), and finally to Telecom Time Slave Clocks (T-TSC) and Cell-site Equipment. Connections are shown using PTP and SyncE.

Route Processor Fail Over

The Route processor fail over (RPFO) or stateful switchover (SSO) feature is supported on the Profile G.8275.1 on the Telecom Boundary Clock. During a switchover, the time error might jump to a high value after losing lock with the T-GM clock. With this feature enabled, the time error will not increase by more than 400 nanoseconds over a switchover.

G.8275.2

Note: Wait for a specific time duration to lapse to build holdover.

G.8275.2 is a PTP profile for telecom networks requiring phase or time-of-day synchronization. It differs from G.8275.1 as it does not require every device in the network to participate in the PTP protocol. G.8275.2 uses PTP over IPv4 in unicast mode.

The G.8275.2 profile is based on partial timing support from the network, meaning nodes using G.8275.2 are not required to be directly connected. This profile is used in mobile cellular systems requiring accurate time and phase synchronization, such as fifth generation (5G) mobile telecommunications technology.

Note: G.8275.2 profile is supported on Cisco NCS 5500 Series Routers. However, performance standards for this profile are not aligned with ITU-T standards as performance specifications for G.8275.2 have not yet been made available by ITU-T. Refer to the PTP Support Information section for hardware supporting G.8275.2 configurations.

Features of G.8275.2 profile:

  • Clock Selection: Defines an alternate BMCA for clock synchronization and port state selection. Parameters include Clock Class, Clock Accuracy, Offset Scaled Log Variance, Priority 2, Clock Identity, Steps Removed, Port Identity, notSlave flag, and Local Priority.
  • Port State Decision: Port states are selected based on the alternate BMCA. A port can be configured to a master-only port state for unicast transport mode.
  • Packet Rates:
    • Synchronization/Follow-Up: Minimum 1 packet-per-second, maximum 128 packets-per-second.
    • Announce packets: Minimum 1 packet-per-second, maximum 8 packets-per-second.
    • Delay-Request/Delay-Response packets: Minimum 1 packet-per-second, maximum 128 packets-per-second.
  • Transport Mechanism: Supports only IPv4 PTP transport mechanism.
  • Mode: Supports transport of data packets only in unicast mode.
  • Clock Type: Supports the following clock types:
    • Telecom Grandmaster (T-GM): Provides timing for other network devices; does not synchronize its local clock to other network devices.
    • Telecom Time Slave Clock (T-TSC): Synchronizes its local clock to another PTP clock but does not provide PTP synchronization to any other network devices.
    • Telecom Boundary Clock (T-BC): Synchronizes its local clock to a T-GM or an upstream T-BC clock and provides timing information to downstream T-BC or T-TSC clocks.
  • Domain Numbers: Network domain numbers range from 44 to 63. The default is 44.

Note: See ITU-T G.8275.2 document for valid values for the Clock Class parameter.

Configuring PTP

Precision Time Protocol (PTP) is a protocol that defines a method to distribute time around a network, based on the IEEE 1588-2008 standard. This module describes the tasks required to configure PTP on Cisco IOS XR software.

Note: When a subinterface is configured with encapsulation default or untag configuration, configure PTP on that subinterface, not the main interface.

Configuring Global G.8275.1 Profile

The following configuration describes steps to create a global configuration profile for a PTP interface, which can then be assigned to any interface. It uses G.8275.1 profile as an example:

RP/0/RP0/CPU0:router# config terminal
RP/0/RP0/CPU0:router(config)# ptp
RP/0/RP0/CPU0:router(config-ptp)# clock
RP/0/RP0/CPU0:router(config-ptp-clock)# domain 24

Configuring PTP Master Interface

The following configuration describes steps to configure a PTP interface as a Master:

RP/0/RP0/CPU0:router(config-ptp-clock)# profile g.8275.1 clock-type T-BC
RP/0/RP0/CPU0:router(config-ptp-clock)# exit
RP/0/RP0/CPU0:router(config-ptp)# profile slave
RP/0/RP0/CPU0:router(config-ptp-profile)# multicast target-address ethernet 01-1B-19-00-00-00
RP/0/RP0/CPU0:router(config-ptp-profile)# transport ethernet
RP/0/RP0/CPU0:router(config-ptp-profile)# sync frequency 16
RP/0/RP0/CPU0:router(config-ptp-profile)# announce frequency 8
RP/0/RP0/CPU0:router(config-ptp-profile)# delay-request frequency 16
RP/0/RP0/CPU0:router(config-ptp-profile)# exit
RP/0/RP0/CPU0:router(config-ptp)# profile master
RP/0/RP0/CPU0:router(config-ptp-profile)# multicast target-address ethernet 01-1B-19-00-00-00
RP/0/RP0/CPU0:router(config-ptp-profile)# transport ethernet
RP/0/RP0/CPU0:router(config-ptp-profile)# sync frequency 16
RP/0/RP0/CPU0:router(config-ptp-profile)# announce frequency 8
RP/0/RP0/CPU0:router(config-ptp-profile)# delay-request frequency 16
RP/0/RP0/CPU0:router(config-ptp-profile)# exit
RP/0/RP0/CPU0:router(config-ptp)# physical-layer-frequency
RP/0/RP0/CPU0:router(config-ptp)# log
RP/0/RP0/CPU0:router(config-ptp-log)# servo events
RP/0/RP0/CPU0:router(config-ptp-log)# commit

Verification

To display the configured PTP profile details, use the show run ptp command.

RP/0/RP0/CPU0:router# show run ptp
Wed Feb 28 11:16:05.943 UTC
ptp
clock
!
domain 24
profile g.8275.1 clock-type T-BC
profile slave
!
multicast target-address ethernet 01-1B-19-00-00-00
transport ethernet
sync frequency 16
announce frequency 8
delay-request frequency 16
!
profile master
!
multicast target-address ethernet 01-1B-19-00-00-00
transport ethernet
sync frequency 16
announce frequency 8
delay-request frequency 16
!
physical-layer-frequency
log
servo events
!

Configuring PTP Slave Interface

This procedure describes the steps involved to configure a PTP interface to be a Slave.

RP/0/RP0/CPU0:router# configure terminal
RP/0/RP0/CPU0:router(config)# interface HundredGigE0/0/0/1
RP/0/RP0/CPU0:router(config-if)# ptp
RP/0/RP0/CPU0:router(config-if-ptp)# profile slave
RP/0/RP0/CPU0:router(config-if-ptp)# port state slave-only
RP/0/RP0/CPU0:router(config-if-ptp)# commit

Verification

To verify the port state details, use the show run interface interface-name command.

RP/0/RP0/CPU0:router# show run interface HundredGigE0/0/0/1
interface HundredGigE0/0/0/1
 ptp
 profile slave
 port state slave-only
!

Configuring PTP Hybrid Mode

This procedure describes the steps involved to configure a router in hybrid mode. Hybrid mode is configured by selecting PTP for phase and time-of-day (ToD) and another source for the frequency.

Note:

  • G.8275.1 PTP profile supports only the hybrid mode. By default, hybrid mode is used, regardless of the physical-layer-frequency configuration.
  • G.8275.2 PTP profile supports both hybrid mode and non-hybrid mode. By default, non-hybrid mode is used. Hybrid mode is used only when the physical-layer-frequency is configured.

To configure PTP Hybrid mode:

  1. Configure Global Frequency Synchronization
    RP/0/RP0/CPU0:router(config)# frequency synchronization
RP/0/RP0/CPU0:router(config)# commit
  2. Configure Frequency Synchronization for an Interface. The time-of-day-priority setting specifies that SyncE is used as a ToD source if no source with a lower priority is available.
    RP/0/RP0/CPU0:router(config)# interface GigabitEthernet 0/0/0/0
RP/0/RP0/CPU0:router(config-if)# frequency synchronization
RP/0/RP0/CPU0:router(config-if-freqsync)# selection input
RP/0/RP0/CPU0:router(config-if-freqsync)# time-of-day-priority 100
RP/0/RP0/CPU0:router(config-if-freqsync)# commit
  3. Configure Global PTP. To configure PTP as a source for ToD, use ToD priority values in the range from 1 (highest priority) to 254 (lowest priority). Use frequency from the physical layer.
    RP/0/RP0/CPU0:router(config)# ptp
RP/0/RP0/CPU0:router(config-ptp)# physical-layer-frequency
RP/0/RP0/CPU0:router(config-ptp)# time-of-day priority 1
RP/0/RP0/CPU0:router(config)# commit
  4. Configure PTP Interface. To enable this interface as a PTP Master, use the master command in ptp-interface configuration mode.
    RP/0/RP0/CPU0:router(config)# interface GigabitEthernet 0/0/0/2
RP/0/RP0/CPU0:router(config-if)# ipv4 address 10.0.0.1/24
RP/0/RP0/CPU0:router(config-if)# ptp
RP/0/RP0/CPU0:router(config-if-ptp)# master ipv4 10.0.0.2
RP/0/RP0/CPU0:router(config-if-ptp)# commit

Verifying PTP Hybrid Mode

RP/0/RP0/CPU0:router # show frequency synchronization selection
Tue Feb 6 06:34:17.627 UTC

Node 0/0/CPU0:
==============
Selection point: ETH_RXMUX (1 inputs, 1 selected)
Last programmed 3d23h ago, and selection made 3d23h ago
Next selection points
SPA scoped : None
Node scoped : None
Chassis scoped: T0-SEL-B 1588-SEL
Router scoped : None

Uses frequency selection
S Input Last Selection Point QL Pri Status
======================== ======================== ===== === ===========
1 GigabitEthernet0/0/0/2 n/a PRC 1 Available

Selection point: LC_TX_SELECT (1 inputs, 1 selected)
Last programmed 3d23h ago, and selection made 3d23h ago
Next selection points
SPA scoped : None
Node scoped : None
Chassis scoped: None
Router scoped : None

Uses frequency selection
Used for local line interface output
S Input Last Selection Point QL Pri Status
======================== ======================== ===== === ===========
7 GigabitEthernet0/0/0/2 0/RP0/CPU0 T0-SEL-B 1 PRC 1 Available

Node 0/RP0/CPU0:
==============
Selection point: T0-SEL-B (3 inputs, 1 selected)
Last programmed 1d00h ago, and selection made 00:36:33 ago
Next selection points
SPA scoped : None
Node scoped : CHASSIS-TOD-SEL
Chassis scoped: LC_TX_SELECT
Router scoped : None

Uses frequency selection
Used for local line interface output
S Input Last Selection Point QL Pri Status
======================== ======================== ===== === ===========
1 GigabitEthernet0/0/0/2 0/0/CPU0 ETH_RXMUX 1 PRC 1 Locked
PTP [0/RP0/CPU0] n/a SEC 254 Available
Internal0 [0/RP0/CPU0] n/a SEC 255 Available

Selection point: 1588-SEL (2 inputs, 1 selected)
Last programmed 3d23h ago, and selection made 00:36:33 ago
Next selection points
SPA scoped : None
Node scoped : None
Chassis scoped: None
Router scoped : None

Uses frequency selection
S Input Last Selection Point QL Pri Status
======================== ======================== ===== === ===========
1 GigabitEthernet0/0/0/2 0/0/CPU0 ETH_RXMUX 1 PRC 1 Locked
Internal0 [0/RP0/CPU0] n/a SEC 255 Available

Selection point: CHASSIS-TOD-SEL (2 inputs, 1 selected)
Last programmed 1d00h ago, and selection made 1d00h ago
Next selection points
SPA scoped : None
Node scoped : None
Chassis scoped: None
Router scoped : None

Uses time-of-day selection
S Input Last Selection Point Pri Time Status
======================== ======================== === ==== ===========
1 PTP [0/RP0/CPU0] n/a 100 Yes Available
GigabitEthernet0/0/0/2 0/RP0/CPU0 T0-SEL-B 1 100 No Available

Configuring PTP Telecom Profile Interface

This procedure describes the steps involved to create an interface for PTP ITU-T Telecom Profiles.

Note: It is also possible to make these definitions within a global PTP profile and attach them to the interface using the profile command in PTP interface configuration mode.

  1. To configure an interface, use interface type interface-path-id command in the configuration mode.
    RP/0/RP0/CPU0:router(config)# interface gigabitethernet 0/1/0/1
  2. To enter the PTP configuration mode for the given interface, use the ptp command in the interface configuration mode.
    RP/0/RP0/CPU0:router(config-if)# ptp
  3. To configure a PTP profile (or specify a previously defined profile), use the profile name command in the ptp-interface configuration mode.

    Note: Any additional commands entered in ptp-interface configuration mode override the global profile settings.

    RP/0/RP0/CPU0:router(config-if-ptp)# profile slave
  4. To configure frequency for Sync or Delay-request messages for the given ptp interface, use sync frequency rate or delay-request frequency rate commands in the ptp-interface configuration mode. Valid values are 2, 4, 8, 16, 32, 64, or 128.
    RP/0/RP0/CPU0:router(config-if-ptp)# sync frequency 128
RP/0/RP0/CPU0:router(config-if-ptp)# delay-request frequency 128
  5. To configure duration for different PTP messages, use announce grant-duration duration, sync grant-duration duration, or delay-response grant-duration duration commands. The duration value can be between 60 and 1000 seconds.

    Note: This duration value represents the length of grant requested by a port in Slave state and the maximum grant-duration allowed when the port is in Master state.

    RP/0/RP0/CPU0:router(config-if-ptp)# announce grant-duration 120
RP/0/RP0/CPU0:router(config-if-ptp)# sync grant-duration 120
RP/0/RP0/CPU0:router(config-if-ptp)# delay-response grant-duration 120
  6. To configure a timeout value (time by which a PTP message must be received before PTSF-lossSync is raised), use sync timeout timeout or delay-response timeout timeout commands. The timeout value can be between 100 to 10000 microseconds.
    RP/0/RP0/CPU0:router(config-if-ptp)# sync timeout 120
RP/0/RP0/CPU0:router(config-if-ptp)# delay-response timeout 120
  7. To configure a response for unicast-grant invalid-request, use unicast-grant invalid-request {reduce | deny} command. The response for requests with unacceptable parameters can be denied or granted with reduced parameters.
    RP/0/RP0/CPU0:router(config-if-ptp)# unicast-grant invalid-request reduce
  8. To configure an IPv4 address for a PTP master, use the master ipv4 ip-address command in the ptp-interface configuration mode.
    RP/0/RP0/CPU0:router(config-if-ptp)# master ipv4 1.7.1.2
  9. To override the clock-class received in Announce messages from the specified Master, use the clock-class class command in the ptp-master-interface configuration mode. Class values range from 0 to 255.
    RP/0/RP0/CPU0:router(config-if-ptp-master)# clock-class 2

Verification

To display PTP interface details, use the show ptp interfaces brief command.

RP/0/RP0/CPU0:router# show ptp interfaces brief
Fri Feb 9 11:16:45.248 UTC

Intf Name Port Number Port State Encap State Line Mechanism
--------------------------------------------------------------------------------
Gi0/1/0/0 1 Slave IPv4 up 1-step DRRM
Gi0/0/0/40 2 Master IPv4 up 1-step DRRM

To verify configured profile details, use the show run interface interface-name command.

RP/0/RP0/CPU0:router# show run interface Gi0/0/0/33
Wed Feb 28 11:49:16.940 UTC
interface GigabitEthernet0/0/0/33
 ptp
 !
 profile slave
transport ipv4
sync frequency 64
clock operation one-step
delay-request frequency 64
!
physical-layer-frequency
!
ipv4 address 21.1.1.2 255.255.255.0
frequency synchronization
 selection input
priority 5
wait-to-restore 0
!

Configuring PTP Telecom Profile Clock

This procedure describes the steps involved to configure PTP clock and its settings to be consistent with ITU-T Telecom Profiles for Frequency.

  1. To enter PTP configuration mode, use the ptp command.
    RP/0/RP0/CPU0:router(config)# ptp
  2. To enter PTP-clock configuration mode, use the clock command in the ptp-configuration mode.
    RP/0/RP0/CPU0:router(config-ptp)# clock
  3. To configure the domain-number for a PTP profile, use the domain number command in the ptp-configuration mode. The allowed domain number range for G.8265.1 profile is between 4 and 23, and for G.8275.1 profile is between 24 and 43.
    RP/0/RP0/CPU0:router(config-ptp)# domain 24
  4. To exit ptp-clock configuration mode, use the exit command.
    RP/0/RP0/CPU0:router(config-ptp-clock)# exit
  5. To configure the desired telecom profile and clock type, use the clock profile {g.8275.1 | g.8275.2} clock-type {T-GM | T-BC | T-TSC} command in ptp configuration mode. For g.8265.1 clock profile, clock type is either master or slave.

    Note: The clock-selection telecom-profile and clock-advertisement telecom-profile commands are deprecated from Release 6.1.2 and replaced by the clock profile command.

    RP/0/RP0/CPU0:router(config-ptp)# clock profile g.8275.1 clock-type T-GM

Verification

To display configured PTP clock profile details, use the show run ptp command.

RP/0/RP0/CPU0:router# show run ptp
ptp
clock
!
domain 24
profile g.8275.1 clock-type T-GM
timescale PTP
time-source GPS
clock-class 6
!
profile master
transport ethernet
sync frequency 16
announce interval 1
delay-request frequency 16
!
profile master1
transport ethernet
sync frequency 64
announce interval 1
delay-request frequency 64
!

To verify that PTP is enabled and the device is in LOCKED Phase, use the show ptp platform servo command.

RP/0/RP0/CPU0:router # show ptp platform servo
Fri Feb 9 11:16:54.568 UTC
Servo status: Running
Servo stat_index: 2
Device status: PHASE_LOCKED
Servo log level: 0
Phase Alignment Accuracy: 1 ns
Sync timestamp updated: 111157
Sync timestamp discarded: 0
Delay timestamp updated: 111157

Configuration Examples

Slave Configuration Example

The following example shows a PTP slave configuration:

interface TenGigE 0/1/0/5
 ptp
 profile slave
 transport ipv4
 port state slave-only
 master ipv4 1.7.1.2
!
announce interval 1
!
ipv4 address 1.7.1.1 255.255.255.0
!

Master Configuration Example

This example shows a PTP master configuration:

ptp
!
profile master
transport ipv4
announce interval 1
!
ipv4 address 1.7.1.2 255.255.255.0
!

PTP Hybrid Mode Configuration Example

This example shows the configuration of PTP hybrid mode:

ptp
time-of-day priority 10
!
interface GigabitEthernet0/1/1/0
 ptp
transport ipv4

ITU-T Telecom Profile Examples:

G.8265.1 Profile Configuration Examples

Master Global Configuration:

ptp
clock
domain 4
profile g.8265.1
!
profile master
transport ipv4
sync frequency 16
announce interval 1
delay-request frequency 16

interface gi 0/2/0/4
ptp
 profile master
transport ipv4
clock operation two-step
!
ipv4 address 17.1.1.1/24

Slave Global Configuration:

ptp
clock
domain 4
profile g.8265.1
!
profile slave
transport ipv4
sync frequency 16
announce interval 1
delay-request frequency 16

interface gi 0/1/0/0
ptp
 profile slave
transport ipv4

G.8275.1 Profile Configuration Examples

Master ipv4 18.1.1.1
port state slave-only
!
clock operation two-step
!
ipv4 address 18.1.1.2/24

Configuring With Clock Type as T-Boundary Clock (T-BC)

ptp
clock
domain 4
profile g.8265.1
!
profile master
transport ipv4
sync frequency 16
announce interval 1
delay-request frequency 16
exit
profile slave
transport ipv4
sync frequency 16
announce interval 1
delay-request frequency 16
exit

interface gi 0/2/0/4
ptp
profile slave
transport ipv4
Master ipv4 17.1.1.1
port state slave-only
!
clock operation two-step
!
ipv4 address 17.1.1.2/24

interface gi 0/2/0/0
ptp
profile master
transport ipv4
clock operation two-step
!
ipv4 address 18.1.1.1/24

Master Global Configuration:

ptp
clock
domain 24
profile g.8275.1
!
profile master
transport ethernet
sync frequency 16
announce interval 1
delay-request frequency 16

interface gi 0/2/0/4
ptp
profile master

G.8275.1 Profile Configuration Examples

transport ethernet
multicast target-address ethernet 01-1B-19-00-00-00
clock operation two-step
!
ipv4 address 17.1.1.1/24

Slave Global Configuration:

ptp
clock
domain 24
profile g.8275.1 clock-type T-TSC
!
profile slave
transport ethernet
sync frequency 16
announce interval 1
delay-request frequency 16

interface gi 0/1/0/0
ptp
profile slave
transport ethernet
multicast target-address ethernet 01-1B-19-00-00-00
!
clock operation two-step
!
ipv4 address 18.1.1.2/24

Configuring With Clock Type as T-Boundary Clock (T-BC)

ptp
clock
domain 24
profile g.8275.1 clock-type T-BC
!
profile master
transport ethernet
sync frequency 16
announce interval 1
delay-request frequency 16
exit
profile slave
transport ethernet
sync frequency 16
announce interval 1
delay-request frequency 16
exit

interface gi 0/2/0/4
ptp
profile slave
transport ethernet
multicast target-address ethernet 01-1B-19-00-00-00
!
clock operation two-step
!
ipv4 address 17.1.1.2/24

interface gi 0/2/0/0
ptp
profile master
transport ethernet
multicast target-address ethernet 01-1B-19-00-00-00
clock operation two-step

G.8275.2 Profile Configuration Examples

! ipv4 address 18.1.1.1/24

Master Global Configuration:

ptp
clock
!
domain 44
profile g.8275.2 clock-type T-GM

profile master
transport ipv4
sync frequency 64
announce frequency 8
unicast-grant invalid-request deny
delay-request frequency 64
!
!
interface GigabitEthernet0/2/0/11
ptp
!
profile master
ipv4 address 17.1.1.1/24

Slave Global Configuration:

ptp
clock
!
domain 44
profile g.8275.2 clock-type T-TSC

profile slave
!
transport ipv4
port state slave-only
sync frequency 64
announce frequency 8
unicast-grant invalid-request deny
delay-request frequency 64
!
log
servo events
best-master-clock changes
!
!
ptp
interface GigabitEthernet0/2/0/12
profile slave
master ipv4 18.1.1.1
!
!
ipv4 address 18.1.1.2/24
!

Configuring With Clock Type as T-Boundary Clock (T-BC)

ptp
clock

G.8275.2 Profile Configuration Examples

domain 44
profile g.8275.2 clock-type T-BC

profile slave
!
transport ipv4
port state slave-only
sync frequency 64
announce frequency 8
unicast-grant invalid-request deny
delay-request frequency 64
!
profile master
!
transport ipv4
sync frequency 64
announce frequency 8
unicast-grant invalid-request deny
delay-request frequency 64
!
log
servo events
best-master-clock changes
!
!
interface GigabitEthernet0/2/0/11
!
ptp
!
profile master
ipv4 address 18.1.1.1/24

interface GigabitEthernet0/2/0/12
ptp
profile slave
master ipv4 17.1.1.1
!
!
ipv4 address 17.1.1.2/24
!

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