Cross-band communication for dual-band router

[funrollloops]

Hey all.

Here's the basic problem I'm having on my home network: I always get very good signal quality and internet connectivity, but I often have issues connecting between nodes on my network. For example, if I'm on my phone and want to view something on my Chromecast, sometimes I'll see my Chromecasts, and other times I won't see any. Another example: I'm on my laptop and want to copy files (using Windows shares) between my desktop (which is also connected via Wifi to the same router)--sometimes it works no problem, other times I'll get an error that the network path cannot be found.

I have a pretty simple setup: Linksys E4200 dual-band router with several devices connected wirelessly. Laptop and desktop (both Windows 8.1) connect with 802.11n adapters (dual-band capable); a couple of Chromecasts; a few mobile devices, etc. .. I have both bands set to the same SSID with the same key. I know I can set separate SSIDs, but I like giving my dual-band clients the option of selecting whichever band is optimal at the time. I don't want to manage that selection manually when devices have the ability to choose the optimal frequency band (right?).

So what I *think* is happening is that some devices are connecting on the 2.4GHz band and others are conecting on the 5GHz band. It seems that my router isn't letting devices on different bands communicate with each-other, but it lets everything connect to the Internet. Does that sound likely? If so, is there any way to allow communication between the bands?

Thanks.

 

[stevech]

or vice-versa.
Some (most?) routers have an option (default is on) to prohibit inter-client packet exchanges, within the same SSID/access device. This is to prevent peer to peer traffic among WiFi users - traffic that doesn't flow through the routing functions. Extreme example: SSID/channel on a WiFi access device in a coffee shop with random users.

You may find this option enabled under names like Isolation, Peer-to-peer in WiFi, and so on.

This presumes you don't have the simple problem of client A talking with client B on YOUR WiFi LAN, where A and B do not have a static LAN IP address, nor a DHCP reservation from your router... so that A and B know each others' unchanging LAN IP address.

 

[funrollloops]

Thanks for the response, stevech. I'll check if there is any kind of peer isolation going on.

With regards to your last statement: What exactly would be the problem with having changing IPs on my wifi LAN? I don't set static IPs or DHCP reservations for any of my devices, so presumably the IPs can change/renew. However, in my experience they generally stay the same for quite a while (the router is probably giving out a long lease time by default).

But even if my IPs were changing every time a node connected, how would that be a problem? As long as my router is managing its DNS entries, there shouldn't be a problem. And whatever kind of voodoo Windows does to resolve "\\hostname\ShareName" (NetBIOS broadcast in the absence of a WINS server, I think) should just work. I think...

 

[stevech]

Thanks for the response, stevech. I'll check if there is any kind of peer isolation going on.

With regards to your last statement: What exactly would be the problem with having changing IPs on my wifi LAN? I don't set static IPs or DHCP reservations for any of my devices, ...

if I'm on my phone and want to view something on my Chromecast

Does the Chromecast device get a DHCP assigned address? If so, how do you know what address to use to connect to it? (I'm unfamiliar with Chromcast).

 

[sfx2000]

There's a setting in the Linksys UI that for some models is inverted, e.g. selected means disabled... "Filter Multicast" is the one if I recall - try setting it to the opposite and see if that helps.

sfx