Dante Clocking on a Cisco SDA Network

There are some considerations to be taken in account when running Dante over a Cisco SDA Network.

Depending on the fabric mode used on the VLAN where Dante devices will be connected, the following scenarios can apply:

• Layer 2 Flooding enabled
  • Multicast traffic will just flow trough: Discovery (mDNS) and Clocking (PTP)
  • There’s a Cisco bug (Bug Search Tool) where any PTP address other that 224.0.1.129 will be blocked
    • That’s not a problem with unmanaged Dante (PTPv1 or PTPv2)
    • Under DDM:
      • It will be a problem for PTPv1 as the default IP address will change (PTP IP addresses used by Dante | Dante). This can be workaround to force the PTPv1 address back to .129 by enabling PTPv2 mode and setting PTPv2 Domain 0.
      • PTPv2 will be OK
• Layer 3 Overlay:
  • Dante PTPv1 has TTL=1 which will not pass across the different switches.
  • This can be workarounded by:
    • Enabling Unicast clocking in at least one device per switch – requires DDM
    • By enabling PTPv2 on the network and Dante devices and having at least 1 Dante device with PTPv2 support on the switches with Dante Devices that only support PTPv1. More here: Dante Devices PTP Clocking Support | Dante
  • Audio Multicast (Dante or RTP [AES67/ST2110]) uses TTL=32