I recently upgrade new switch called ESW540-24P gigabit switch from old Catalyst Express 500 so I wanted to switch the Width Channel from 20 MHz to 40 MHz on autonomous IOS, however, 5 GHz band allow me to use 40 MHz in order to pull full 300 Mbps but I am having issue with 2.4 GHz, when I choice from Width Channel, there is ONLY 20 MHz option. There was no 40 MHz like earlier IOS on either IE or Chrome. I am on 153-3.JAB so is this IOS affected to autonomous IOS to everyone if having problem with Width Channel?
I will discovering on which code that has it. Once I found it, I will let you know that there has the code. I had 1252 in past but I had to recently upgrade because of it required to have higher than 15.4W to use both radios.
Many enterprise access points will not allow you to set 40mhz on the 2.4ghz. You can only find those at the local store when buying home router/wifi. You should be fine with the 2.4ghz and 802.11n enabled to be honest. Even if you went with a 3600 or 3700, it will not allow you to set 40mhz on the 2.4ghz. If you also look at 802.11ac, that allows 80mhz, but only available on the 5ghz.
40 Mhz channel width on 2.4 Ghz does NOT exist in an enterprise-grade wireless access point, like Cisco's. And if you understand 2.4 Ghz wifi, you'd be asking-for-trouble if you want a channel width of 40 Mhz on an over-crowded frequency spectrum like 2.4 Ghz.
With default 20 Mhz you get, at most, three non-overlapping channels. Now if you increase this to 40 Mhz, you'll wind up with two non-overlapping channels. Now have you tried sniffing out your home for any channel interference from neighbors' WiFi (which is most likely to be running on the same 2.4 Ghz spectrum)?
40 Mhz channel-width for 2.4 Ghz no longer exist in enterprise-grade AP because of this very reason: There is no room to switch channels.
You will find this in SOHO APs because this is one way for manufacturers to sell their stuff, common-sense or not. 5 years ago, maybe, not all homes have wireless. Nowadays, you'll be hard pressed to find a home NOT to have any form of wireless device (AP, DECT phone). Again, just by this reinforces the logic of the decision to remove the option to enable 40 Mhz channel-width on the 2.4 Ghz radio.