16 xlr to cat5e to dsnake or usb on QU16? for stage box.

Forums Forums Qu Forums Qu general discussions 16 xlr to cat5e to dsnake or usb on QU16? for stage box.

This topic contains 33 replies, has 8 voices, and was last updated by Profile photo of [XAP]Bob [XAP]Bob 5 years, 4 months ago.

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  • #55713
    Profile photo of [XAP]Bob
    [XAP]Bob
    Participant

    Collisions don’t happen – networks are full duplex with store and forward, so there is only ever one packet going in each direction along a particular piece of cable.

    Now a switch might have to hold a packet for a small fraction of a second, but that isn’t a collision.

    For collisions you need either a non duplex system or a hub.
    Both are now considered stone age.

    #55716
    Profile photo of Lou
    Lou
    Participant

    Bob, Fibre or ethernet? Did you mistype or are you talking two different things?

    #55717
    Profile photo of Andreas
    Andreas
    Moderator

    Indeed, we’re running off topic, so I’ll also put a final note. 😉

    Using TP cables and switches there only are peer-to-peer connections with separated transmit and receive paths (full duplex connection). Technically there is no chance for collisions, even if plenty devices are concurrently connected to the same switch and sending data.
    The switch exactly knows to which port he has to forward particular packets and keeps them inside internal send buffers until the target port is idle. There are also priority queues to decide which packet will be sent next and which may have to wait even longer.
    The switch takes care of this, nothing the Qu or the stagebox has to bother with.
    While there are no collisions, packet loss may still occur if the bandwith of the target port can’t handle the traffic in time and the switch runs out of packet buffers.
    That’s why it is essential to prioritize dSnake traffic over anything else when building VLANs to ensure nothing gets lost there. Other communication like QuPad control are running via TCP which easily deals with lost (and even duplicated) packets.

    #55719
    Profile photo of [XAP]Bob
    [XAP]Bob
    Participant

    @Lou
    It doesn’t matter – collisions are a thing of the past.
    You can still soak the bandwidth of a switch (the backplane is unlikely to be able to handle the full capacity of every port it has) causing packet loss.

    One of the easy ways to do this is with a broadcast storm or, ironically, with Spanning Tree Protocol – which should stop broadcast storms in the first place…

    Of course the real issue with the store and forward approach is jitter – you can’t be sure that the time between each packet is identical, especially if other packets are large. *That* requires careful network design/testing.

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