- Preface
- Overview
- Using the Command-Line Interface
- Configuring the Switch Alarms
- Performing Switch Setup Configuration
- Configuring Cisco IOS Configuration Engine
- Configuring Switch Clusters
- Performing Switch Administration
- Configuring PTP
- Configuring PROFINET
- Configuring CIP
- Configuring SDM Templates
- Configuring Switch-Based Authentication
- Configuring IEEE 802.1x Port-Based Authentication
- Configuring Web-Based Authentication
- Configuring Interface Characteristics
- Configuring Smartports Macros
- Configuring VLANs
- Configuring VTP
- Configuring Voice VLAN
- Configuring STP
- Configuring MSTP
- Configuring Optional Spanning-Tree Features
- Configuring Resilient Ethernet Protocol
- Configuring Flex Links and the MAC Address-Table Move Update Feature
- Configuring DHCP
- Configuring Dynamic ARP Inspection
- Configuring IP Source Guard
- Configuring IGMP Snooping and MVR
- Configuring Port-Based Traffic Control
- Configuring SPAN and RSPAN
- Configuring LLDP, LLDP-MED, and Wired Location Service
- Configuring CDP
- Configuring UDLD
- Configuring RMON
- Configuring System Message Logging
- Configuring SNMP
- Configuring Network Security with ACLs
- Configuring QoS
- Configuring Auto-QoS
- Configuring EtherChannels
- Configuring Static IP Unicast Routing
- Configuring IPv6 Host Functions
- Configuring Link State Tracking
- Configuring IPv6 MLD Snooping
- Configuring Cisco IOS IP SLAs Operations
- Configuring Layer 2 Network Address Translation
- Troubleshooting the Cisco IOS Software
- Working with the Cisco IOS File System, Configuration Files, and Software Images
Cisco IE 2000 Switch Software Configuration Guide, Cisco IOS Release 15.0(2)EB
Bias-Free Language
The documentation set for this product strives to use bias-free language. For the purposes of this documentation set, bias-free is defined as language that does not imply discrimination based on age, disability, gender, racial identity, ethnic identity, sexual orientation, socioeconomic status, and intersectionality. Exceptions may be present in the documentation due to language that is hardcoded in the user interfaces of the product software, language used based on RFP documentation, or language that is used by a referenced third-party product. Learn more about how Cisco is using Inclusive Language.
- Updated:
- February 11, 2018
Chapter: Configuring PTP
Configuring PTP
Finding Feature Information
Your software release may not support all the features documented in this chapter. For the latest feature information and caveats, see the release notes for your platform and software release.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Prerequisites for Configuring PTP
Restrictions for Configuring PTP
Information About Configuring PTP
Precision Time Protocol
The IEEE 1588 standard describes the use of PTP for fault-tolerant synchronization of network real-time clocks.
The clocks in a PTP network are organized into a master-slave hierarchy. The grandmaster clock is called the Best Master Clock (BMC), and is the root of the master-slave clock hierarchy. PTP uses the BMC algorithm to identify the master clock for synchronization.
The master clock is a time source on the network that can be synchronized to a highly accurate time source such as a Global Positioning System (GPS) clock. The slaves are the other network devices that synchronize their clocks to the master clock. The parent is the clock to which the member-slave clocks synchronize. Timing messages between the master and slave clocks ensure continued synchronization.
Synchronization behavior depends on the PTP clock setting mode that you configure on the switch. The mode can be boundary, end-to-end transparent, or forward:
- A switch clock in boundary mode participates in the selection of the most accurate master clock. If more accurate clocks are not detected, that switch clock becomes the master clock. If a more accurate clock is found among the slave clocks, then the switch synchronizes to that clock and becomes a slave clock. After initial synchronization, the switch and the connected devices exchange timing messages to correct the changes caused by clock offsets and network delays.
- A switch clock in end-to-end transparent mode synchronizes all switch ports with the master clock. This switch does not participate in master clock selection and uses the default PTP clock mode on all ports.
- A switch clock in forward mode allows incoming PTP packets to pass-through the switch as normal multicast traffic.
When the switch is in PTP forward mode, PTP configuration is not available except when changing PTP mode to another mode. You can only configure per-port PTP when the switch is in boundary mode.
How to Configure PTP
Default PTP Settings
By default, PTP is enabled on all the Fast Ethernet and Gigabit Ethernet ports on the base switch module. The default PTP mode on all ports is end-to-end transparent.
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Setting Up PTP
Monitoring and Maintaining the PTP Configuration
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Displays the PTP FastEthernet properties on the specified port. |
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Displays the PTP Gigabit Ethernet properties on the specified port. |
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Troubleshooting the PTP Configuration
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Additional References
The following sections provide references related to switch administration:
Related Documents
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Standards
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No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature. |
MIBs
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To locate and download MIBs using Cisco IOS XR software, use the Cisco MIB Locator found at the following URL and choose a platform under the Cisco Access Products menu: http://cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml |
RFCs
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No new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature. |
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