Funny story, as part of a mega alliance we have had issues with a couple hosting providers blackholing our mumble servers. We have so many new connections when big events happen that they auto-detect it as a DDOS.

That sounds like a really interesting feature! Trying to find some documentation on this specific feature but it's hard to find exactly what you're talking about.

1) Can you elaborate how "hierarchical chat room" works and how fleets in Eve Online use this?

2) Do other game chat apps like Discord implement anything similar?

Mumble's channel system allows nesting channels, in addition to that, each channel allows specific access control list that could be both inherited from top-level channel or be inherited to a lower-level one. In addition to that it has the possibility of creating groups of users to whom the permission applies. It's really sophisticated. Discord has only role-based rooms, but nothing hierarchical.

I don't have any experience with gaming so this is a bit hard for me to understand. Are nested channels used as a way of grouping channels in a hierarchy in the UI? Or does the hierarchy affect what people hear? In the latter case, I'm imagining something like: "Everyone in subchannel can hear everything said in parent channel, but not vice versa".

The hierarchy can be set up to affect what people hear, and where they can speak. This is invaluable when you need to coordinate dozens or hundreds of players in real time. You can set up overlapping rooms where team leads hear their team member's voice chatter and their superior's voice chatter, and have the option of communicating in either direction. I usually had the two side buttons on my mouse set to push-to-talk, one that for talking up the hierarchy, one for talking downward. The exact setup everyone uses varies, but at minimum you can have a room for higher-level voice chat among team leads, while each lowest-level team is isolated to their own channel and can focus on the tasks given to them by their team lead. Mumble is also flexible enough that you don't need to strictly adhere to a hierarchy, you can have your lower-level players also be able to communicated laterally to groups of specialists who are handling specific support tasks.

This is all a difficult communication problem, but it's doubly difficult because decisions need to propagate up and down your communication hierarchy in seconds. Being able to manage this level of communication without it being a hopeless clusterfuck is a defining feature of effective organizations of players.

How do you configure where your push-to-talk transmits? I installed it but can only find one PTT function, and the documentation didn't really help...

You transmit in the channel you're in usually.

Correct. In example, you've got your "logisitics" wing; in this context that's your healers. A commander ("logi-FC") within the channel issues orders to the sub-channel members, and no one outside the channel hears that. All members can still hear the parent channel.

In fights with 20-50 on each side particularly, it's really something to have the "pulse of the fight" because as a healer you can tell how well that's going.

A mumble server can be hosted with fairly low requirements if you're an org with less than 50 members in voice comms, and it's pretty embarrassing that a seemingly large majority of corporations can't even get 5 people into a call without an act of congress when gamers have tools like this so well explored.

That really sounds like an indispensible feature. Is Mumble the only voice chat system that provides this kind of hierarchical linking of channels, or is it available on other systems as well?

If it's not available on, say, Discord, why is that? Do people just somehow make do without it? Or is there some other compensating feature?

Teamspeak does it too, but it scales a lot less.

Discord only allows you to be a membere of one channel at a time.

It is not an uncommon set-up for fleets to have the important people have their own channel talking about secret stuff and another one for the rest of the fleet.

Then the ones from the secret channel have two buttons set up, one to talk just to them and one to talk with the entire fleet.

Discord is all about being dead simple, and nested channels necessarily require more configuration complexity on both the server and client.

So, while the feature is a must-have for a small subset of users, it's probably not seen as being worth the trouble when just supporting several flat channels is more than enough for the 99% of Discord's potential user base.

I'd still hope they at least add some kind of "broadcast to several channels" option, since that seems like the simplest version that would still be useful, but I don't really expect it.

In large eve fleets, it's not a chattering mob, you couldn't run things if it's like that. Things are normally quite terse with a small number of people, scouts, FCs, logi talking while most people get on with the important business of pressing F1.

Sorry, missed the point, I see what you mean now. Kinda sad in a way. I love the massive fleet aspect of eve. Even tho TiDi fights can be pretty awful, they're amazing in their own way.

The key part for eve is that you can configure it so that fleet commanders (people running raids/operations in game) can broadcast to players under their chain of command, without squad level chatter going the other way.

Not from direct experience, we used a much simpler setup for some events on a minecraft server to allow for team voice.

You could just like you know, start up a mumble client and test it yourself.

Also important is the "priority speaker" function which let's a certain group, or channel automatically be louder than local chatter. So you can have a small subgroup actively coordinating and the fleet commander can give orders which don't get lost.

Mumble also has much better security/permissions. Last time I looked it was pretty easy to dump the list of active users on a discord "chat". That means you could always know if someone was forming for an attack etc.

I still haven't figured out the hierarchical channel structure/channel linking.

The use case I had was if I wanted teamchat/allchat done via different hotkeys, like if I were playing with some friends on an RTS and wanted to talk crap on all while strategizing on team.

Edit: my two cents: I've been running Mumble for a long time, and though it isn't as multi-tooled as TS, I love its simplicity and its quality.

When I tried to get into Eve, I applied to a couple corps, and they both used discord. Maybe because they were newbie-focused?

We actually use both. Discord is great for "pinging" fleets, i.e. sending out a bat-signal to all members that a fleet needs to form for whatever reason. It's also good for general text chat (talking about market/industry/memes). If the corporation you joined was small and not a member of a larger alliance, then they may not have needed Mumble.

However, if you join a large alliance/coalition, fleets can easily get to 100+ player counts, and a single discord voice chat room becomes unusable. It is extremely important that you follow the fleet commander's instructions during a fleet. That is where Mumble shines with the fleet commander residing in a top level voice channel, with other members in lower-level voice channels that he cannot hear. It also allows for lower-level members to join voice channels designated as "quiet", so you don't have to listen to the chatter of 100 drunk Eve players during a Friday night fleet.

Discord is generally used for day to day chat in corps, then you'll be told to get on Mumble for fleet ops. Some corps continue to use Discord for small fleet ops but as soon as you're doing ops with Alliances or blue corps you'll nearly always end up on Mumble.

Lots of corps use discord, but at an alliance level you'll often end up with mumble for comms. Another 'dead' open source software that's used is Jabber (XMPP) for 'pings' aka broadcasts to tell people there's a fleet up.