Q1 What is Clear-Com’s recommendation in terms of running IPTs using 1ms PTP packet size?

A1 Avoid it in systems without PTP aware switches.

Q2 I know Clear-Com prefers to use 125μs PTP,  but if I had to run at 1ms PTP, are there any short comings I should look out for?

A2 The risk is with loss of DECT sync due to PTP packets getting delayed behind RTP-audio packets in the Eth-Switch buffers.

We use PTP to generate the local RF DECT sync within each antenna, this enables Beltpacks to roam between antennas.

If the jitter on the PTP is too much then this can lead to a lack of RF DECT sync . We can handle up to ±1000ns.

If you had to use IPTs with 1ms PTP on a network without PTP aware switches..

The solution to such a scenario is to physically isolate the wireless network from other traffic. By this we mean to not only place the wireless traffic in its own VLAN but to also use a separate trunk access ports for that VLAN between switches (rather than placing the IPT-VLAN on a trunk with all the other traffic). Furthermore the IPA card should be made PTP master of this isolated wireless network. This markedly reduces the chance of collisions and therefore jitter is minimized.

 Using 10 Gbps up-links between switches is potentially an alternative solution here but there is still a limit and a possible bottleneck in the network and could still lead to scenarios where it will be difficult to roam between IPTs.

 (see https://clear-com.atlassian.net/wiki/spaces/SF/pages/771784722 )

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