Time Capsule as DHCP Router and DNS server for larger network - too taxing?

Question

Ok, let me say first that I'm no networking expert, but I have tried to learn a decent amount over the years. I haven't got quite gotten o the level of combing router event logs, though I intend to do that as my next step. My question here though is if my overall network strategy is flawed.
My setup at home is one that may be a bit more extensive than most users have:
Cable modem -> Time Capsule -> Multiple gigabit switches (business grade) -> Wired Cat5e throughout the house and 2 Airport Extremes. I don't know how many total wired and wireless clients I have, but it may be between 30 and 40 (only a few are computers with the rest being game systems, networked DVRs, audio streamers, NAS, etc)
At the moment, the Time Capsule only backs up one machine - a MBP (I have external HDDs connected directly to the desktops). I don't use the TC's HDD for anything else. Also, I have the network configured so that the TC handles DHCP addressing and NAT. The Airport Extremes are in bridge mode.
For the most part, everything works very well. Internet speeds are good, audio streaming works well, no problems with TC backups, etc. The only issue I've run into are dropouts when streaming video content on the network from one device to another (not form the internet). Basically, the stream will pause and then an error will pop up on screen saying that there was a network problem. Now, I know that the specific devices themselves may have issues of their own, but since it's happened on more than one system, I'm wondering if there is a common network culprit- expecting the Time Capsule to handle its duties especially while it is doing a backup.
Here are a few thoughts I have:
1 - From a technical standpoint, I don't know if all client to client network traffic goes through the TC. I was thinking that communication could happen between devices on the same switch without having to go up to the TC and then back down, but maybe I'm wrong. If I am wrong, that certainly is a bottleneck right there. I'm not segregating the video streamers to their own subnet on a new router to isolate the traffic. I'm also not sure if the bottleneck is impacted by static vs dynamic IP addressing. IOW, I don't know if setting the devices up with static IPs would change the flow of traffic to not have to go through the TC (just flow across the switch) or not.
2 - Long ago in a different network setup, I had allowed the wireless access points to assign IPs. However, I found that doing so sometimes created problems accessing some of those devices from a computer or device on a different subnet. As such, I switched over to having the router connected to the modem do all the IP addressing. Maybe this is a bad idea given the temporary nature that some devices will hop on and off the network.
3 - Additionally, in the interests of getting better wireless coverage over the whole house, I switched to using 2 airport extremes configured to use the same SSID (so that devices moving around the house wouldn't need to specifically change networks in order to get better signal). I guess I could let one of those 2 handle IP addressing while the other is in bridge mode (pointing to the primary Extreme vs the TC).
4 - Kind of getting back to the TC as the bottleneck, maybe it shouldn't handle network wide DHCP and NAT duties. If TC backups take network priority, such that other kinds of traffic could hiccup, then I probably need to rethink where the TC should exist in the network. Or, maybe it would be enough to just have the stream sensitive components be on their own subnet.
I know there are potentially multiple flaws in my current strategy, so any suggestions or attempts at correcting my assumptions would be helpful.
Thanks!
Jeff
Message was edited by: Rgbyhkr
Message was edited by: Rgbyhkr

Answer 1

Welcome to the discussions!
1 - Everything goes through the router when it is setup to handle DHCP and NAT
2 - You want your main router, the TC, to handle all DHCP and NAT functions. It will handle up to 250+ connections, so 30-40 devices won't be much of a challenge
3 - Keep both AirPort Extremes in bridge mode to allow the TC to handle the things in #2 above. If you setup an Airport Extreme to give out IP addresses, you'll create a Double NAT issue on your network...which can slow down communications between devices...the thing you are trying to avoid. If you use Xbox live or other interactive services, the online features will not function with a Double NAT on your network.
4 - You want the TC to handle all DHCP and NAT functions as in #2. I assume that you have no single run of CAT5e more than 300 feet.
5 - If you want to create separate sub nets correctly (the AirPorts won't allow you to do this as they are designed for basic home networking), you'll need to look at routers for professional and commercial use, like Cisco.
With as many devices as you have, you may be running out of bandwidth at times. If you only notice the issue during Time Machine backups, and you don't need to backup each hour, take a look at Time Machine Editor to setup backups whenever you like, maybe once a day at 2 AM when things on the network are quiet.
My suggestions are of course opinions. Hopefully you'll receive some other possibly differing views.