I have ordered Nanopi R6C to connect WAN and then use the LAN to connect to switch I'm planning to connect to Grandstream GWN7701M (Unmanaged[Not ordered yet] and from there connect to Orbi to run as AP.
Managed vs. Unmanaged Switch:
I’m planning to get a Grandstream GWN7701M (unmanaged switch) for my setup, but I’m wondering if it’s worth getting the managed switch (GWN7701PA) instead. My primary concern is future-proofing, especially since the GWN7701PA supports 2.5G ports Would the managed switch be a better choice even if I don’t immediately need those features?
QoS on Router vs. Switch:
My router (R6C running OpenWrt) will handle most of the routing and traffic management. Would OpenWrt’s QoS be sufficient, or is it advisable to get a managed switch for additional traffic prioritization and QoS at the switch level?
Direct Fiber Connection to Switch:
The GWN7701M switch supports SFP+ modules. Is it possible to connect the fiber cable from my ISP directly to the switch using a compatible SFP+ transceiver? If so, what type of transceiver should I get? (My ISP uses EPON media box)
Using a Switch for WAN Traffic:
Can I configure the switch to handle WAN traffic and route all data to the R6C for processing (running OpenWrt)? For instance, if I connect the fiber cable to the switch (via SFP+), could I use WAN traffic and forward it to the R6C while maintaining LAN connectivity on the same switch? If this setup is possible, what would be the best way to configure it? If its not recommended should I go for unmanaged switch ?
for 1 GBit/s switches, we've come to a price range where getting an L2-managed switch 'just in case' can be worthwhile, especially if you include the used markets into your research. The general price level for faster than 1 GBit/s however makes this less attractive, so getting a 'cheap' unmanaged option now and a managed one a couple of years down the line, when you actually need it might make more sense.
QoS needs to happen on the choking point, your router. QoS features of L2+/ L3 managed switches can only help you prioritizing traffic in your lan, they aren't very effective at competing with sqm/ cake on your router.
there is no general answer to this, it depends on the actual requirements of your ISP. While there are ISPs that just require a 'media conversion' between fibre and copper, most contemporary ISPs use GPON - which requires a compatible (and accepted by the ISP!) GPON-ONT (fibre ~modem) to work. That's something for you to find out. Yes, it might sound attractive to do away with this and replace the dedicated ONT with a SFP variant, but in practice the situation is more nuanced. In either way, you still need the same kind of device - just in a different form-factor, so the gains aren't as big as they might sound. Furthermore these SFP ONTs are running rather hot (and yes, they do suck power out of the SFP cage as well), which might pose its own share of problems. As far as you are concerned, the dedicated ONTs are rather effective (in terms of power consumption), easier to cool - and 'should' appear to be transparent to you. So unless there's an actual problem, it makes little sense to muck with this. See 4. for a continuation.
A switch is a switch, a router is a router - both work on different ISO levels and do different things (yes, L3 switches muddy the waters here). What you can do on a managed switch, is set up the VLAN matrix of your switch to pass one port to the WAN port of your router - and its LAN (trunk-)port back to the switch for further distribution to your access ports. This can make sense in some environments, but unless you really know what you're doing, I'd advise against this - just keep it simple (KISS principle), it's typically easier to get a grasp on dedicated cables you can touch (bonus points if you get red/ green patch cables for this purpose and label your router ports accordingly. But there's another catch, if your managed switch does handle WAN traffic, it's also (kind of) exposed to the internet, which raises the bar on its security status - a lot of cheap managed switches fail this bar (as they expose their management interface on all VLANs) and even good/ higher end switches need a lot more attention (accidental misconfiguration and security issues of the switch, so you need to keep them maintained/ updated and non-EOL, with active vendor support). Yes, you can do it - it might make sense in some environments (and may be tempting, but unless you know what you're doing, keep the switch updated at all times and are willing to replace your switch when the vendor decides to EOL it, I'd recommend against this.
It is not (at all) clear to me what specific services you refer to, Grandstream's marketing pages are just bull^wbuzzword bingo.
OpenWrt can run on managed switches, even on certain 2.5 GBit/s switches - but the rtl93xx support necessary for 2.5 GBit/s is not really at a level to be used by ordinary users (the support is very unrefined, with gaps and experimental; rtl838x support for several 1 GBit/s switches is relatively mature (but not 100% feature complete either)). OpenWrt has no cloud services (OpenWISP and similar is possible, but for rather advanced users) and won't give you QoS services on your switch either (big question if you really need those, on the switch).
You can use 'any' managed (or unmanaged) switch with OpenWrt though.