What is says in the topic: there's a Wireless N access point to which I'd like to connect using the 5 GHz band exclusively. How does one accomplish this? Using the directive band=a in the connection configuration file in /etc/NetworkManager/system-connections doesn't seem to affect anything (/var/log/syslog still shows attempts by wpa_supplicant to connect using the 2.4 GHz band), and running iwconfig wlan0 freq 5G per this question results in the following error:

Error for wireless request "Set Frequency" (8B04) :
    SET failed on device wlan0 ; Invalid argument.

[Edit] I'm hoping the answer won't depend on the hardware in use, but here's some information about the hardware, just in case:

System is an Asus ZenBook Prime UX31A-DB51, running Ubuntu 12.04.

lspci output:

00:00.0 Host bridge: Intel Corporation Ivy Bridge DRAM Controller (rev 09)
00:02.0 VGA compatible controller: Intel Corporation Ivy Bridge Graphics Controller (rev 09)
00:04.0 Signal processing controller: Intel Corporation Device 0153 (rev 09)
00:14.0 USB controller: Intel Corporation Panther Point USB xHCI Host Controller (rev 04)
00:16.0 Communication controller: Intel Corporation Panther Point MEI Controller #1 (rev 04)
00:1a.0 USB controller: Intel Corporation Panther Point USB Enhanced Host Controller #2 (rev 04)
00:1b.0 Audio device: Intel Corporation Panther Point High Definition Audio Controller (rev 04)
00:1c.0 PCI bridge: Intel Corporation Panther Point PCI Express Root Port 1 (rev c4)
00:1c.1 PCI bridge: Intel Corporation Panther Point PCI Express Root Port 2 (rev c4)
00:1d.0 USB controller: Intel Corporation Panther Point USB Enhanced Host Controller #1 (rev 04)
00:1f.0 ISA bridge: Intel Corporation Panther Point LPC Controller (rev 04)
00:1f.2 SATA controller: Intel Corporation Panther Point 6 port SATA Controller [AHCI mode] (rev 04)
00:1f.3 SMBus: Intel Corporation Panther Point SMBus Controller (rev 04)
00:1f.6 Signal processing controller: Intel Corporation Panther Point Thermal Management Controller (rev 04)
02:00.0 Network controller: Intel Corporation Centrino Advanced-N 6235 (rev 24)

The driver for the wireless interface is iwlwifi.