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Example: Configure PTP over Ethernet for Multicast TimeTransmitter, TimeReceiver, and Dynamic Ports
In PTP over Ethernet networks, the timeTransmitter sends the announce, synchronization, and delay-response packets using the multicast method. If any unicast delay-request message is received, the timeTransmitter disregards the message and does not send delay-response messages to the timeReceiver. A PTP timeReceiver receives the multicast announce packets from the timeTransmitter or multiple primaries and determines the best timeTransmitter using Best TimeTransmitter Clock Algorithm (BTCA). A timeReceiver receives and processes the synchronization from the selected timeTransmitter clock. The timeReceiver sends delay-request messages to this timeTransmitter using the multicast method and processes the delay-response messages from the timeTransmitter to establish synchronization.
Both the link-local MAC address and the standard 802.3 multicast MAC address can be present in a system. However, a PTP interface supports only one of the following at a point in time:
-
Layer 2 multicast with link-local MAC address
-
Layer 2 multicast with standard multicast MAC address
-
PTP over IPv4
When you configure both IPv4 and Ethernet encapsulation, the unicast-negotiation configuration applies only to IPv4 encapsulation. It is not effective for PTP over Ethernet operation.
When you configure a logical interface by using the stateful statement at
the [edit protocols ptp] hierarchy level, each interface that you configure
as a stateful is considered to be both a timeTransmitter and a timeReceiver port. Although an
ACX Series router supports up to 32 timeTransmitter ports and 4 timeReceiver ports, you can
configure only 4 unique logical interfaces as potential PTP masters by using the
stateful statement because the interface is treated as both a timeReceiver
and a timeTransmitter interface. You cannot configure the interface that you specify to be a
stateful with the master or slave statements.
This example shows how to configure a timeTransmitter port, timeReceiver port, and a stateful port for PTP over Ethernet and PTP over IPv4 encapsulation, and how to configure unicast and multicast mode of transmission of PTP traffic among the timeTransmitter and timeReceiver nodes.
Requirements
This example uses the following hardware and software components:
-
An ACX Series router
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Junos OS Release 12.3X51 or later
Overview
While an ACX Series router supports the PTP over Ethernet functionality, a grandmaster clock such as an MX Series router or a TCA Series Timing TimeReceiver does not support PTP over Ethernet. Consider a sample deployment in which an ACX Series router named ACX1 functions as a boundary clock with a PTP timeReceiver port using IPv4 as the encapsulation mode and timeTransmitter ports using Ethernet as the encapsulation mode for PTP traffic. ACX1 contains two potential timeReceiver interfaces, one that is fixed as a timeReceiver-only port using IPv4 on the link toward an MX Series router named MX2, and a stateful port that functions as a timeReceiver using PTP over Ethernet on the link toward another ACX Series router named ACX2. In addition, ACX1 also contains a port that is a timeTransmitter-only port using PTP over Ethernet and connects to the base station.
In this example, the router uses either interface ge-0/2/0.0 or ge-0/2/1.0 as the selected timeReceiver interface based on the announce messages received from the timeTransmitter and the port that was selected using the Best TimeTransmitter Clock Algorithm (BTCA). The interface ge-0/1/4.0 is always in the timeTransmitter state. According to the IEEE 1588 specification, if port ge-0/2/0.0 is selected as the timeReceiver interface, interface ge-0/2/1.0 transitions to the timeTransmitter state. If interface ge-0/2/1.0is selected as the timeReceiver port, interface ge-0/2/0.0 transitions to the listening state. You can also configure the interface ge-0/1/4.0 as a timeReceiver only interface for PTP over Ethernet, if necessary, for completeness of the configuration.
Configuration
In this example, you configure a timeTransmitter port, a timeReceiver port, and a stateful port for PTP over Ethernet and PTP over IPv4 encapsulation. You can also configure unicast and multicast modes of transmission of PTP traffic among the timeTransmitter and timeReceiver nodes.
- CLI Quick Configuration
- Configure PTP over Ethernet for Multicast Master, Slave, and Dynamic Ports
- Results
CLI Quick Configuration
To quickly configure this example, copy the following commands, paste them in a text
file, remove any line breaks, change any details necessary to match your network
configuration, and then copy and paste the commands into the CLI at the
[edit] hierarchy level:
set interfaces ge-0/1/4 description “to base-station” set interfaces ge-0/1/4 unit 0 family inet address 7.1.1.37/24 set interfaces ge-0/2/0 description “to MX2” set interfaces ge-0/2/0 unit 0 family inet address 110.1.1.2/24 set interfaces ge-0/1/4 description “to ACX2” set interfaces ge-0/1/4 unit 0 family inet address 110.1.1.2/24 set protocols ptp clock-mode boundary set protocols ptp domain 110 set protocols ptp slave interface ge-0/2/0.0 unicast-mode transport ipv4 set protocols ptp slave interface ge-0/2/0.0 unicast-mode clock-source 110.1.1.250 local-ip-address 110.1.1.2 set protocols ptp master interface ge-0/1/4.0 multicast-mode transport ieee-802.3 set protocols ptp stateful interface ge-0/2/1.0 multicast-mode transport ieee-802.3
Configure PTP over Ethernet for Multicast Master, Slave, and Dynamic Ports
Step-by-Step Procedure
The following example requires you to navigate various levels in the configuration hierarchy.
To configure the timeTransmitter, timeReceiver, and dynamic interfaces, and a boundary clock with unicast and multicast mode of transmission of PTP packets in PTP over IPv4 and PTP over Ethernet topologies:
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Configure the timeTransmitter interface, and enter edit mode for the interface.
[edit interfaces] user@host#edit ge-0/1/4
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Configure a description for the interface.
[edit interfaces ge-0/1/4] user@host#set description to base-station
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Configure a logical unit and specify the protocol family.
[edit interfaces ge-0/1/4] user@host#set unit 0 family inet
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Specify the address for the logical interface
[edit interfaces ge-0/1/4 unit 0 family inet] user@host#set address 7.1.1.37/24
-
Configure the timeReceiver interface, and enter edit mode for the interface.
[edit interfaces] user@host#edit ge-0/2/0
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Configure a description for the interface.
[edit interfaces ge-0/2/0] user@host#set description to-MX2
-
Configure a logical unit and specify the protocol family.
[edit interfaces ge-0/2/0] user@host#set unit 0 family inet
-
Specify the address for the logical interface
[edit interfaces ge-0/2/0 unit 0 family inet] user@host#set address 110.1.1.2/24
-
Configure the stateful interface, and enter edit mode for the interface.
[edit interfaces] user@host#edit ge-0/2/1
-
Configure a description for the interface.
[edit interfaces ge-0/2/1] user@host#set description to-ACX2
-
Configure a logical unit and specify the protocol family.
[edit interfaces ge-0/2/1] user@host#set unit 0 family inet
-
Specify the address for the logical interface
[edit interfaces ge-0/2/1 unit 0 family inet] user@host#set address 110.2.1.1/24
-
Configure the clock mode as boundary clock.
[edit protocols ptp] user@host# set clock-mode boundary
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Specify the PTP domain value.
[edit protocols ptp] user@host# set domain 110
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Configure the local timeReceiver interface from which the boundary timeTransmitter receives time and passes it on to the configured timeReceiver clocks.
[edit protocols ptp] user@host# edit slave interface ge-0/2/0.0
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Configure the upstream unicast PTP timeTransmitter clock source parameters.
[edit protocols ptp slave interface ge-0/2/0.0] user@host# edit unicast-mode
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Configure the encapsulation type for PTP packet transport.
[edit protocols ptp slave interface ge-0/2/0.0 unicast-mode] user@host# set transport ipv4
-
Configure the PTP timeTransmitter parameters by specifying the IP address of the PTP timeTransmitter clock and the IP address of the local interface.
[edit protocols ptp slave interface ge-0/1/0.0 unicast-mode] user@host# set clock-source 110.1.1.250 local-ip-address 110.1.1.2
-
Configure the timeTransmitter interface in this example.
[edit protocols ptp] user@host# edit master interface ge-0/1/4.0
-
On the timeTransmitter interface, configure multicast transmission for downstream PTP timeReceiver clocks.
[edit protocols ptp master interface ge-0/1/4.0] user@host# edit multicast-mode
-
On the timeTransmitter interface, configure the encapsulation type as Ethernet for PTP packet transport.
[edit protocols ptp master interface ge-0/2/1.0 multicast-mode] user@host# set transport ieee-802.3
-
Configure the dynamic or stateful interface in this example.
[edit protocols ptp] user@host# edit stateful interface ge-0/2/1.0
-
On the dynamic interface, configure multicast transmission for downstream PTP timeReceiver clocks.
[edit protocols ptp stateful interface ge-0/2/1.0 ] user@host# edit multicast-mode
-
On the dynamic interface, configure the encapsulation type as Ethernet for PTP packet transport and the link-local multicast address to be used.
[edit protocols ptp stateful interface ge-0/2/1.0 multicast-mode] user@host# set transport ieee-802.3 link-local
Results
In configuration mode, confirm your configuration by entering the show
command. If the output does not display the intended configuration, repeat the
configuration instructions in this example to correct it.
[edit protocols ptp]
user@host# show
clock-mode boundary;
domain 110;
slave {
interface ge-0/2/0.0 {
unicast-mode {
transport ipv4;
clock-source 110.1.1.250 local-ip-address 110.1.1.2;
}
}
}
master {
interface ge-0/1/4.0 {
multicast-mode {
transport ieee-802.3;
}
}
}
stateful {
interface ge-0/2/1.0 {
multicast-mode {
transport ieee-802.3 link-local;
}
}
}
After you have configured the device, enter the commit command in
configuration mode.
Verify PTP over Ethernet Multicast Dynamic, TimeTransmitter, and TimeReceiver Settings
Confirm that the configuration is working properly.
- Verifying the PTP Clock Details
- Verify the Lock Status of the Slave
- Verify the PTP Options on the Slave
- Verify the PTP Options and the Current Status of the Master
- Verify the Number and Status of the PTP Ports
- Verify PTP Statistics
Verifying the PTP Clock Details
Purpose
Verify that the PTP clock is working as expected.
Action
In operational mode, enter the run show ptp clock command to display
comprehensive, globally configured clock details.
Meaning
The output displays the clock details, such as the encapsulation method used for
transmission of PTP traffic and the number of configured stateful or dynamic ports.
Although a stateful port functions as either a timeReceiver or a timeTransmitter port,
the value displayed in the Stateful Ports field denotes the dynamic
ports that you explicitly configured. The number of dynamic ports is not computed and
displayed in the fields that display the explicitly configured timeTransmitter and
timeReceiver ports. For more information about the run show ptp
clock, see show ptp clock
in the CLI explorer.
Verify the Lock Status of the Slave
Purpose
Verify that the timeReceiver clock is aligned to the timeTransmitter clock by checking the lock status of the timeReceiver.
Action
In operational mode, enter the run show ptp lock-status command to
display the lock status of the timeReceiver.
Meaning
The output displays information about the lock status of the timeReceiver. The output
shows whether the timeReceiver is aligned to the timeTransmitter clock or not, and the
interface name configured for PTP on the timeReceiver. The Master Source
Port field displays the address of the timeTransmitter clock when PTP over
IPv4 is configured and the multicast MAC address of the source when PTP over Ethernet
is configured. For more information about the run show ptp
lock-status operational command, see in the show ptp lock status.
Verify the PTP Options on the Slave
Purpose
Verify the PTP options that are set on the timeReceiver and the current status of the timeTransmitter.
Action
In operational mode, enter the run show ptp slave command to display
the configured timeReceiver.
Meaning
The output displays information about the configured timeReceiver and the status of
the timeReceiver. For more information about the show ptp slave
operational command, see in the show ptp
slave.
Verify the PTP Options and the Current Status of the Master
Purpose
Verify the PTP options that are set for the timeTransmitter and its current status.
Action
In operational mode, enter the run show ptp master command to
display the configured options for the timeTransmitter.
Meaning
The output displays information about the configured timeTransmitter and the current
status of the timeTransmitter. For more information about the run show ptp
master operational command, see in the show ptp master.
Verify the Number and Status of the PTP Ports
Purpose
Verify the number of PTP ports and their current status.
Action
In operational mode, enter the run show ptp port command to display
the configured ports.
Meaning
The output displays information about the number of ports created according to the
configuration and their current status. The name of the interface configured for PTP
and the number of times a stateful port transitioned from the timeReceiver to the
timeTransmitter state and vice versa is displayed. For more information about the
run show ptp port operational command, see in the show ptp port.
Verify PTP Statistics
Purpose
Verify the statistical details of the PTP configuration.
Action
In operational mode, enter the run show ptp statistics command to
display the statistical information regarding the configured PTP clocks.
Meaning
The output displays brief or detailed information about the operation of configured
PTP clocks. Statistical parameters include information such as the total number of PTP
packets transmitted or received by a timeTransmitter or timeReceiver interface and the
number of various messages (such as announce and synchronization messages) that are
sent between a timeTransmitter and a timeReceiver. For more information about the
show ptp statistics operational command, see show ptp statistics .