Basic networking question

[DeanoVIP]

To build a picture for this simple question.  My house is three floors first floor consist of the fiber connection coming into the router, and a lounge TV with a Roku box.  Middle floor has a second TV connected to a ROKU box, along with a mesh repeater.  The top floor has another TV /w a chromecast.  The Jellyfin server is on the top floor, which is installed on Windows and uses a TP Link 1300 Wifi adapter which connects to the mesh repeater over 5ghz and gets 300mbps down and 70 up.  

My whole house is using wifi and over 5ghz, while the top floor can connect to the router it gets a better connection off the repeater.  My server is on the local LAN only, no outside streaming.

When I load the Jellyfin app on the top floor TV how does it stream it, does the server send the stream to the repeater-router then back up to the repeater and to the TV?  Curious on the route it takes in the network or does the tv just get the stream directly from the server?

[TheDreadPirate]

In this setup, all requests go all the way back to the router. My understanding is that repeaters, or nodes in a mesh network, do not have any routing logic. They send everything back to the main router.

[Fate]

In this setup, all requests go all the way back to the router.  My understanding is that repeaters, or nodes in a mesh network, do not have any routing logic.  They send everything back to the main router.

Lets assume both clients are in the same SSID and in the same Subnet, which sounds like is the case here, then traffic is directly exchanged via intra-BSS relay on that mesh AP. 
No routing necessary.

Everything outside that SSID/Subnet will be send to the router.

The setting to disabled this is usually called "client isolation". I also assume this is unchecked.

[mildlyjelly]

In this setup, all requests go all the way back to the router.  My understanding is that repeaters, or nodes in a mesh network, do not have any routing logic.  They send everything back to the main router.

Lets assume both clients are in the same SSID and in the same Subnet, which sounds like is the case here, then traffic is directly exchanged via intra-BSS relay on that mesh AP. 
No routing necessary.

Everything outside that SSID/Subnet will be send to the router.

The setting to disabled this is usually called "client isolation". I also assume this is unchecked.

I understand how intra-BSS works on an access point or a router, and I can see how that would apply to a mesh node. But, since mesh nodes are connected in a way that access points and routers typically aren't, I was uncertain if intra-BSS would still work across multiple mesh nodes?

Typically, for example, an access point can't directly communicate with another access point. So, if 2 devices are connected to 2 different access points, the traffic has to get sent through the router.
But on a mesh network, all nodes can either directly or indirectly communicate with each other. So if you have 2 devices connected to 2 different nodes, in theory, they could send traffic directly between them (or indirectly through other nodes) without ever sending traffic through the controlling router.

Do you know if this multi-node intra-BSS behavior is a thing implemented mesh routers?

[DeanoVIP]

Is there a way to check if this BSS behaviour is enabled my Router is a Fritzbox 7530 and the repeater is a Fritz! Repeater 3000. I should elaborate the reasoning for my post, my downstairs TV tends to buffer more on HEVC content my CPU is only a i5 6500 so I am considering to get a i5 7500T for better QSV support. Now I'm stuck with wireless but I could in theory wire in my downstairs ROKU box. I also have the issue where my Server decides at random it will go to 2.4ghz instead of 5ghz and that causes havoc streaming, to counter this I'm proposing to buy a better wifi card for the machine, probably a PCI one rather than a USB power one.