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macbook123

macrumors 68000
Original poster
Feb 11, 2006
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What I'm wondering about is this: We have a Comcast modem with WiFi that is hooked up straight to the cable coming into one side of the house. We also have a new Airport Extreme which I connected to the router with a long Ethernet cord so I would be able to have strong WiFi on the opposite side of the house (we also have an older Airport Extreme which I use to wirelessly extend the signal into the yard, but that's not relevant to this discussion I think).

What I wonder about is this: is there a way to configure the Comcast modem and the new Airport Extreme such that my devices (phone, tablet, laptop) will switch network automatically as I go from one side to the other of the house? I know that the two Airport Extreme's trade off supplying the devices automatically, but I don't know if the same can be done between the modem and Airport extreme attached to it via ethernet.

Thanks for any advice you might have.
 

techwarrior

macrumors 65816
Jul 30, 2009
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Colorado
Yes, you can do this. The AP Extreme(s) connected by Ethernet can either use the same SSID and password, or a unique name and password and devices will connect to whichever Wi-Fi access point is strongest. For simplicity, use the same name and password. Use different if you want dumb devices (that don't remember multiple Wi-Fi connections) to connect to a specific access point. Macs, PCs, and iOS devices can switch from one network name to another as they can remember multiple networks, but Apple TV, and many IoT devices can only remember a single Wi-Fi network.

When you setup the Airport device(s), use bridge mode for the Network connection type and "Create a Network" on the Wi-Fi network settings. This creates what Apple refers to as a Roaming Wi-Fi network. All NAT and DHCP will be managed by the Comcast router, the Extreme(s) in bridge mode will effectively be limited service Access Points that bridge Wi-Fi to the Ethernet LAN.

If you decide to use the third Extreme, also connect it via Ethernet to the router, or to the other Extreme. You generally don't want to use Wi-Fi extending as the radio splits it's capacity between links to the clients and links to the other Extreme or Router. If Ethernet is not practical, consider MOCA or Powerline adapters to put Ethernet traffic over unused coax cables, or power wiring in your home, and if you go this route, don't go cheap as older adapters had poor performance. Expect to pay $75-100 for adapter sets if you need to go this route.

The Comcast router should need no modifications if the other Access Points (extremes) connect via Ethernet.

Also, be prepared to tweak channels on both 2.4 and 5GHz bands, if they overlap between your Wi-Fi Access devices, or neighbors, the collisions of network packets will slow things down miserably.
 
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macbook123

macrumors 68000
Original poster
Feb 11, 2006
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Thanks a lot, techwarrior. Seems like I'm close. In this bridge mode, do I have to give the Comcast router the same network name as the AP Extremes? Or should the devices be able to switch between network names automatically?
[doublepost=1495325279][/doublepost]Also, do I have to switch the Comcast router/modem to bridge mode?
 

techwarrior

macrumors 65816
Jul 30, 2009
1,250
499
Colorado
Thanks a lot, techwarrior. Seems like I'm close. In this bridge mode, do I have to give the Comcast router the same network name as the AP Extremes? Or should the devices be able to switch between network names automatically?
[doublepost=1495325279][/doublepost]Also, do I have to switch the Comcast router/modem to bridge mode?

The Comcast router can have the same network name as the Extreme(s), if you do that, make sure you use the same password and wireless security setting so that devices can connect to any of the WiFi devices. Or, you can use different if you want to choose. Either way, your devices will connect to the best signal to access your network.

iPhones, Macs, PCs can "remember" multiple networks. But some devices can only be configured for one network, and different names can let you choose which network to join. The network name makes no difference once the data hits the network and goes out through the modem, network names and passwords simply act as an authentication method to access your network via Wi-Fi and keep others off the network.

The Comcast router needs to be a router, not a bridged device. Bridging turns off routing functions like DHCP, NAT, Firewall and changes a device from a router to a simple access point. You need at least one router, and since the Comcast device has the modem built in, it needs to be the router.
 

macbook123

macrumors 68000
Original poster
Feb 11, 2006
1,869
85
Thanks. OK, let me make sure I understand. Let's say I call the comcast router network "comcast" and the Airport Extreme's network "apple". What I'm trying to achieve is that as I walk from the part of the house where "apple" is emitting to the part where "comcast" is emitting, that my iPad/Android phone/laptop will automatically switch to the stronger network. Currently they're not doing that, since they can see both networks at all times, be it one significantly more weakly. I want them to switch to the stronger network. Are you saying if I have the Airport Extreme in bridge mode my devices will e.g., use the Airport's signal even if I'm connected to the "comcast" network? Or am I still misunderstanding you? Thanks so much for the help!

The Comcast router can have the same network name as the Extreme(s), if you do that, make sure you use the same password and wireless security setting so that devices can connect to any of the WiFi devices. Or, you can use different if you want to choose. Either way, your devices will connect to the best signal to access your network.

iPhones, Macs, PCs can "remember" multiple networks. But some devices can only be configured for one network, and different names can let you choose which network to join. The network name makes no difference once the data hits the network and goes out through the modem, network names and passwords simply act as an authentication method to access your network via Wi-Fi and keep others off the network.

The Comcast router needs to be a router, not a bridged device. Bridging turns off routing functions like DHCP, NAT, Firewall and changes a device from a router to a simple access point. You need at least one router, and since the Comcast device has the modem built in, it needs to be the router.
 

techwarrior

macrumors 65816
Jul 30, 2009
1,250
499
Colorado
Thanks. OK, let me make sure I understand. Let's say I call the comcast router network "comcast" and the Airport Extreme's network "apple". What I'm trying to achieve is that as I walk from the part of the house where "apple" is emitting to the part where "comcast" is emitting, that my iPad/Android phone/laptop will automatically switch to the stronger network. Currently they're not doing that, since they can see both networks at all times, be it one significantly more weakly. I want them to switch to the stronger network. Are you saying if I have the Airport Extreme in bridge mode my devices will e.g., use the Airport's signal even if I'm connected to the "comcast" network? Or am I still misunderstanding you? Thanks so much for the help!

In terms of direct WiFi communications, if you are connected to comcast, the device will not use the airport. If you are connected to apple, the device will not use the comcast. You will not tend to see devices switching networks until the signal is too weak to use.

Devices are not smart enough to know it is all the same underlying network, and switching is disruptive, so they tend to avoid doing so.

If you use the same WiFi name on all, devices will switch a bit more readily because they will assume it to be the same underlying network, but even that is somewhat disruptive so they will only switch when there is a clear reason to do so. You are unlikely to get a pure result either way due to this resistance to change access points. But, in the end, all you really need is for the network range to be extended to reach areas where the signal is too weak with a single router. So, which device a client connects to is less critical than the actual service you receive from the collective network.
 

Altemose

macrumors G3
Mar 26, 2013
9,189
488
Elkton, Maryland
Thanks. OK, let me make sure I understand. Let's say I call the comcast router network "comcast" and the Airport Extreme's network "apple". What I'm trying to achieve is that as I walk from the part of the house where "apple" is emitting to the part where "comcast" is emitting, that my iPad/Android phone/laptop will automatically switch to the stronger network. Currently they're not doing that, since they can see both networks at all times, be it one significantly more weakly. I want them to switch to the stronger network. Are you saying if I have the Airport Extreme in bridge mode my devices will e.g., use the Airport's signal even if I'm connected to the "comcast" network? Or am I still misunderstanding you? Thanks so much for the help!

Ideally, you would configure the Comcast router in addition to the Apple AirPort to use a common network name (e.g. 'Smith Wireless') with a common security method (WPA 2 Personal) and common password. This would allow clients to roam freely from one access point to another as they will all have the same network name (SSID). Note that this setup does not work as well as an entirely one vendor network (e.g. all Apple AirPorts, all UniFi APs, etc.) as there is variation in the transmit abilities of each device. Therefore, you may need to adjust the transmit power on each unit to allow clients to roam properly.
 
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