The development of AfterDark. Project Clay X - Netgear M4250 Audiophile Switch for Merging HAPI MKII x Giesemann OCXO

[El Guapo]

10 hours ago, AfterDark. said:

Merging HAPI MKII can set Netgear M4250 as Master

The role of M4250 is simply a PTP transparent clock, TC. @Erik Haas the M4250 is not the boundary clock (cost issue, maybe). It cannot be the master clock in Ravenna/AES67 network. M4250 only update the time stamp when packet leave.
 

Normally the M4250 needs a local NTP server to calibrate the internal clock for more accurate time stamp. Install a ref clock module to calibrate the internal clock of M4250 surely helps offline operations.
 

@The Computer Audiophile in my recent Intel E810 project I found the M4250 still needs to change some switch settings before selecting AV template. For example the switch’s DSCP value 34 and 46 default priority were the same. Must assigned it correctly otherwise the PTP message and the audio stream would be treated equal. Usually we use DSCP 34 for audio / 46 for PTP by AES67 media profile standard. But some times I prefer using Ravenna standard 46 for audio / 48 for PTP.

 

1. manually select trust mode to DSCP

 

2. set the priority mapping correctly 

 

3. assign the proper DSCP priority

[El Guapo]

7 hours ago, Erik Haas said:

Does the streaming computer also need to be equipped with a network card that is PTP compatible?

90% condition you don’t need specific NIC for Ravenna/AES67 on computer. I tested some Realtek, Aquantia, Broadcom and Intel’s they are all good for Ravenna network. The only exception is the 10GbE on Mac has driver issue that prevent you to use Ravenna/AES67.
 

The driver in computer side don’t need hardware time stamp. Only in software mode. Computer side don’t even send PTP delay request…