Any way to force a specific 802.11X protocol?

Alex, once you reconfigure your router for "n" all you need to do is go into each Macs Network Pref and select the new network. For your newer hardware you will immediately experience speed gains on the "n" only network.

Naturally, any older hardware (b/g compatible) will no longer see the new network. So you will need to "bridge" another router setup specifically for this older protocol. Then go into each of these older Macs Network Prefs and select this b/g compatible network. Keeping the 2 networks seperate will improve things for both hardware styles.

Alex,

On the Macs in question, go to System prefs --> Network. Click on Airport on the left. Which network is shown beside "Network Name"? If it isn't the nework you desire, then click "Advance" in the lower right. Here is a list of networks this particular machine has joined over time. Is the network you prefer it to be on in the list? Is it not at the top of the list? The Airport software will always default to the top most active network. (Alternatively, if you don't see the desired network, you'll need to add it via the "+" button.) You can rearrange the list by dragging your preferred network to the top of the list and clicking "OK".

Then in the "Network Name" drop-down, select the network you had earlier dragged to the top, and click "Apply". From this point on it should default to that one at the top of the list. Once you have shut down the older network, it wouldn't hurt to go into each Mac and deleting that now inactive network. Let us know if this helps.

Alex, you can't unless you broadcast ONLY in that specific protocol. All wireless devises will default to the slowest protocol available if other (older) devises on the network can only access it via the slower protocol. Your network speed cannot exceed the lowest common denominator. If you have a b/g/n network, and all the devises were "n", then all devises would reach "n" speeds. But the moment you introduce a "b" or "g" devise into the network, EVERYBODY drops to the slower speed. Does this make sense?

Alex, I have a Cisco AP-1131AG 802.11a/g WAP at home and I've overcome the problem by setting the a and g networks to different SSIDs. They also use different encryption keys. The only way I've been able to consistently get my MBP to always attach to the a network is to not have a network profile/preference set to the g network in System Preferences -> Network -> Advanced -> Preferred Networks. I use the a network and the kids use the g network.

Periodically however, the MBP doesn't see the a network so since it doesn't have the g network information it can't connect. I suspect this is an OS X issue but I don't have another a device to verify that the a network is still connecting. The WAP reports 'authentication failed' and then 'packet to client reached max retries, removing the client'. I resolve this by disabling and then re-enabling the MBP AirPort.

There seems to be an issue with OS X not always abiding by the Preferred Network order so only the above solution works. Incidentally, not too long ago Apple changed OS X so each network location profile maintains its own set of configurations. This is a bit of a pain for me with my cellular broadband card (I have to remember to switch between location profiles or create a configuration for every location profile). I wish OS X had an option to mark certain configurations as 'global' to work across every location. 🙂

Anyway you can also manage the issue with say one location profile for work and another for home, etc. Is your enterprise using the same SSID for all protocols? If so, then different encryption keys would accomplish the same thing but I don't know if that's possible at the protocol level.

Are you using an Aironet 1250? I wish there was a way to communicate these issues to Apple but this is way too technical for the AppleCare folks. There just doesn't seem to be a way for sophisticated customers to get to the higher level support folks and with no corporate level support organization, we just have to wait and hope someone notices the problem and fixes it.

Alex,

For what it is worth, the university that I work at seems to be having a similiar problem. We are using Cisco 1100 and 1200 APs with 802.11a/b/g networks. For some reason the Macs will try to connect to the 'a' network only and have a hard time getting online. I have looked in many different forums to find a way to force the mac clients into 'g' only mode from the computer itself, but the general consensus is that there is not a way to do this. If anyone knows how to force the mac to use a specific network protocol (in Leopard) please reply here.

Thank you.

I am in the same situation, I work in a hospital environment, the APs are Cisco devices that broadcast on a/b/g. We have many wireless workstations connecting to these APs as well as communication devices that can only operate on b. When these comm devices connect to an AP all other devices connected via b have to disconnect and reconnect at random. Our IT department was able to force some of our Wireless workstations to only use a and the connection dropping issue resolved. Now I need to do the same with my MacBook Pro. I need to set it to only connect to a... but I can't determine which SSID is a/b/g... I can see the Channel, but trying the various channels doesn't seem to resolve the issue.

has anyone found a solution?