VEP 7 Bonjour Service Errors

I don't use VEP, but since you've not had other answers yet: I suspect those errors are a symptom of whatever's crashing VEP, rather than the cause. "Bonjour" is a system that allows applications on different computers to find each other on a network: so VEP is trying to advertise its status (e.g. which computer it's on and, I imagine, what services it can provide.) When its status changes, it has to update its status record - i.e. re-advertise. It looks like it has occasional periods of rapid status change, therefore rapid re-advertisement, and is getting throttled.

I'd probably go looking at other system logs, and in the VEP logs, to see if there's anything that matches the timing of those update avalanches (remembering that logs are sometimes written in local time, sometimes GMT.) Could be lots of things, but examples of what I'd be looking for: other services losing contact with the network, or change of network (e.g. address, hostname...), or hardware sleeping. Hopefully that gets you started...?

aldous said:

I don't use VEP, but since you've not had other answers yet: I suspect those errors are a symptom of whatever's crashing VEP, rather than the cause. "Bonjour" is a system that allows applications on different computers to find each other on a network: so VEP is trying to advertise its status (e.g. which computer it's on and, I imagine, what services it can provide.) When its status changes, it has to update its status record - i.e. re-advertise. It looks like it has occasional periods of rapid status change, therefore rapid re-advertisement, and is getting throttled.

I'd probably go looking at other system logs, and in the VEP logs, to see if there's anything that matches the timing of those update avalanches (remembering that logs are sometimes written in local time, sometimes GMT.) Could be lots of things, but examples of what I'd be looking for: other services losing contact with the network, or change of network (e.g. address, hostname...), or hardware sleeping. Hopefully that gets you started...?

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Thanks for your insight! What further puzzles me is that I'm on one machine so VEP isn't calling on anywhere other than local instances. Interestingly, the number of errors per event is always around the same amount and may correlate with the number of instances in my VEP session. It could be that everything is performing fine but the Bonjour service (historically a network printing protocol if I'm not mistaken?) has a threshold of how many requests it thinks is normal and VEP greatly exceeds this in its function. Am I completely off on that line of thought?

georgewmusic said:

Thanks for your insight! What further puzzles me is that I'm on one machine so VEP isn't calling on anywhere other than local instances.

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If you don’t need other instances to connect, then you can probably turn off the advertisement… and looks like my faith in the devs has been repaid:
Turning off “Advertise on local network” should stop it using Bonjour. Then it’s just a matter of waiting to see if it still crashes: if yes, it was just a symptom of something else.

georgewmusic said:

It could be that everything is performing fine but the Bonjour service (historically a network printing protocol if I'm not mistaken?) has a threshold of how many requests it thinks is normal and VEP greatly exceeds this in its function. Am I completely off on that line of thought?

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Yes, definitely, that line of thought is about right… there is such a threshold, but I’d expect VEP to leave a wide margin between its usage and that limit. Also looks like the advertisement is associated with the server per-machine (rather than per-instance)… if that’s right, the instance count shouldn’t really be a problem unless it’s trying to run each instance as a separate server.

aldous said:

If you don’t need other instances to connect, then you can probably turn off the advertisement… and looks like my faith in the devs has been repaid:

Vienna Ensemble Pro Preferences | VSL - Software Manuals

www.vsl.info

Turning off “Advertise on local network” should stop it using Bonjour. Then it’s just a matter of waiting to see if it still crashes: if yes, it was just a symptom of something else.

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I really hoped you'd be right with this tip but having just tried it (changed the setting and then restarted everything) it still made tons of errors come through in event viewer when loading in. It still uses Bonjour with that tick box cleared so it must be some kind of internal process. Back to the drawing board!

if that’s right, the instance count shouldn’t really be a problem unless it’s trying to run each instance as a separate server.

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I think that's actually how VEP works. I could be wrong but I think every instance does behave as it's own server seeing as they're the root level of hosting in the program and can be moved from computer to computer.

georgewmusic said:

I really hoped you'd be right with this tip but having just tried it (changed the setting and then restarted everything) it still made tons of errors come through in event viewer when loading in.

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I'm pretty surprised; thought that would be a dead cert: if it's not advertising, you shouldn't get that error. It's definitely the same error? And it hasn't forgotten the setting or something: it remains unchecked? No other errors in the VEP logs?

From there, most of the other debugging options are fairly technical, and possibly more hassle than asking VSL for support... but, I'd probably grab Process Explorer from Sysinternals and look at which processes are making Bonjour/mDNS noises; and/or find a way to look at what's being advertised via a utility like dns-sd (unless it's a recent addition, I think that's still something you'd need to get from the Bonjour SDK for Windows.)

georgewmusic said:

I think that's actually how VEP works. I could be wrong but I think every instance does behave as it's own server seeing as they're the root level of hosting in the program and can be moved from computer to computer.

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I think we're probably just tripping up on terminology: in the screenshots on this page, it shows the machine as the server (in your case, just a single entry for "127.0.0.1 64-bit localhost"), where the single server contains your multiple instances, all listed underneath. Do you see more than that? Or is it possible you have any older versions/servers running?

I'd expect that single server to be responsible for advertising on behalf of all its instances, and I'd expect it to combine its instances' data into a single update - exactly so it scales. If it doesn't behave that way, then VSL support would know... but I'd expect this error to be much more common than it seems to be.

Okay, this gets more interesting. I was wrong about that untick working - sort of.

It seems whatever the problem is is directly related to specific instances rather than the program as a whole.

After unticking, it's now only throwing 3 errors per loading of my template. To be clear, this doesn't happen when loading the program, only my template. Having spammed F5 in event viewer during the loading procedure I can deduce its actually related to potentially two instances, one of which is disabled (I'm guessing this as the errors come through once these two have loaded). I'm going to make a copy of the project and delete these two instances and see if it works without errors. Watch this space.

Update - Can confirm, this is definitely tied to two instances in my template. When removed from the project file it loads without throwing any errors.

georgewmusic said:

After unticking, it's now only throwing 3 errors per loading of my template. [...]
Update - Can confirm, this is definitely tied to two instances in my template. When removed from the project file it loads without throwing any errors.

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Nice! So my follow-up questions would then be: (a) do the errors also return with only one or other of those instances loaded, or does it need both to get the errors? (b) leaving both problematic instances unloaded, do the errors come back when you re-enable "advertise on network"?

It seems the errors occur for both (one for one instance and two for the other). I haven't tried re-enabling that tick yet but will let you know.

Edit: Incidentally, whilst poking around in VEP I discovered my template was using an outdated VST2 version of Kontakt. So at least even if I never get to the bottom of this, I'm now running on the up-to-date VST3 version

Glad you've been able to narrow it down. So I guess there's probably something special about those two instances: these state-thrashing issues often turn out to be something self-referential or circular in some way... so, for example, that might be a VEP instance that contains a plugin that tries to connect to a VEP instance (or contains a Kontakt instance which contains a plugin which, etc, etc).

One other possibility: there's nothing special about those instances, and they happen to be the ones loading when you go over some limit. Should be easy to rule that out by loading them by themselves and checking you still get the errors, though.