Basic principles of Clear-Com products use of PTP / AES

  1. Basic principles

When using AES67 / ST2110-30 digital audio networks they require the following network provisioning.

  • High bandwidth, Guaranteed bandwidth to support audio streams, Low network latency and Very low network jitter.

  • The use of QoS, IGMP and VLANS to separate the AES67/ ST2110 steams from other data on the network.

  • A Ethernet switch fabric made up of enterprise grade switches that support boundary / transparent clock mode

  • Ensure Spine / Leaf uplinks are large enough to support all end points on the leaf receiving audio.

 Often for small to medium AES67/ ST2110 networks are easier to implement using layer 2 network

 

Each Clear-Com PTP endpoint device (IPA card / Iris panel / IPT transceiver) uses the following protocols.

  •  PTP data packets MultiCast - to sync the GM on the network

  • AES67 audio data packets Unicast to pass audio between IPA card and the Iris or IPT

  • Auto discovery using mDNS of Clear-Com only devices.

 

  • ST2110-30 audio data packets Multicast to pass AES67 audio between

  1. AES67 trunk lines between Clear-Com matrices

  2. The IPA card and 3rd party AES67 devices.

 

AES67/SMPTE 2110 streams must be in the multicast IP range (239.0.0.0 – 239.255.255.255)

PTP uses multicast destination IP address 224.0.1.129 as per IEEE 1588 standards

How do Clear-Com devices join a Grandmaster (GM) PTP domain?

If an IPA card is set into PTP slave mode it will sync to the GM on the network

The IPA PTP settings must match the GM PTP profile (domain #, announce interval, sync internal etc)

 Once the IPA card discovers and registers (associates) with any Iris panels or IPT transceiver on the network it sends the same PTP profile information to the Iris / IPT endpoint device (via the AES67 admin address). The Iris / IPT will then join the GM PTP domain and obtain PTP sync.

at EHX V12.1 : Even whew in slave mode the settings in the IPA screen are the ones that are send to the IPT / Iris panels. Therefore the IPA settings should match the GM settings