Cisco Nexus 3548 series - Licensing Requirements for PTP; Guidelines and Limitations for PTP

Licensing Requirements for PTP
PTP requires no license. Any feature not included in a license package is bundled with the Cisco NX-OS
system images and is provided at no extra charge to you. For a complete explanation of the Cisco NX-OS
licensing scheme, see the Cisco NX-OS Licensing Guide.
Guidelines and Limitations for PTP
• In a Cisco Nexus 3500 only environment, PTP clock correction is expected to be in the 1- to 2-digit
range, from 1 to 99 nanoseconds. However, in a mixed environment, PTP clock correction is expected
to be up to 3 digits, from 100 to 999 nanoseconds.
• PTP operates only in boundary clock mode. End-to-end transparent clock and peer-to-peer transparent
clock modes are not supported.
• PTP operates when the clock protocol is set to PTP. Configuring PTP and NTP together is not supported.
• PTP supports transport over User Datagram Protocol (UDP). Transport over Ethernet is not supported.
• PTP supports only multicast communication. Negotiated unicast communication is not supported.
• PTP is limited to a single domain per network.
• PTP-capable ports do not identify PTP packets and do not time-stamp or redirect those packets to CPU
for processing unless you enable PTP on those ports. This means that if the PTP is disabled on a port,
then the device will be capable of routing any multicast PTP packets, regardless of their type, assuming
that there is a multicast state present for this. None of these multicast PTP packets from this port will be
redirected to CPU for processing, because the exception used to redirect them to the CPU is programmed
on a per-port basis, based on whether the PTP is enabled or not on the respective port.
• 1 packet per second (1 pps) input is not supported.
• PTP over IPv6 is not supported.
• Cisco Nexus 3500 Series switches support a maximum of 48 PTP sessions.
• Cisco Nexus switches should be synchronized from the neighboring master using a synchronization log
interval that ranges from –3 to 1.
• Beginning with Cisco NX-OS Release 6.0(2)A8(7), all unicast and multicast PTP management messages
will be forwarded as per the forwarding rules. All PTP management messages will be treated as regular
multicast packets and process these in the same way as the other non-PTP multicast packets are processed
by Cisco Nexus 3500 switches.
• Cisco Nexus 3500 Series switches do not support PTP on 40G interfaces.
• You must configure the incoming port as L3/SVI to enable forwarding of the PTP unicast packets.
Default Settings for PTP
The following table lists the default settings for PTP parameters.
Cisco Nexus 3548 Switch NX-OS System Management Configuration Guide, Release 7.x
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Configuring PTP
Licensing Requirements for PTP