I know it's been a while since my last post, but I've been quite busy researching and testing a lot of wireless products; but the good news is I'm going to tell you all about them! Below is a list of the topics I will be blogging about in the posts to come, so stay tuned!
- Autonomous vs. Lightweight Access Points (LWAPs)
- 802.11N Networking and 2.4Ghz vs 5Ghz bands
- Wireless Spectrum Analyzers and troubleshooting tools
- How to deploy a second Access Point for increased coverage
- Deploying Cisco Aironet 1140 series Access Points
- My new Linksys E2500 Advanced Dual-Band N Router
Let's get started on the first topic; Autonomous vs. LWAPs. I'm going to make a very bold assumption here that 90% of you reading this are at least a little familiar with Autonomous APs; (you might not know it yet, but you are) these are typically any consumer wireless router available at your local computer outlet that you administer yourself, such as a Linksys, Netgear, Belkin, or D-Link wireless router.
Cisco also has a myriad of Autonomous APs (hereafter known as APs) such as the Cisco 800 series, for SOHOs; and the Cisco Aironet 1100 series, for small to mid-sized businesses. Cisco and other vendors also offer these popular Access Points in another flavor known as a Lightweight AP or LWAP. LWAPs are not autonomous and are not locally administered by the Network Administrator; instead, they obtain wireless network related settings such as their Wireless SSID, WEP/WPA/WPA2 keys, VLAN, and other settings from a Wireless LAN Controller (WLC).
LWAP and WLCs are an attractive solution for Network Administrators who manage dozens if not hundreds of Access Points throughout their company, because they automate deployments and relieve the burden of manually configuring new APs. Every LWAP connected to the network downloads it's unique configuration from the WLAN Controller, this also means device management is centralized to a single point on the network. One thing you other consultants or network admins should know about Cisco Aironet Access Points, particularly the 1100 series, is that they come in both flavors. If you read my very first post in this blog, I discussed how I was not able to manually configure a brand new Cisco Aironet 1130-AG, because we accidentally ordered an LAP instead of an AP model; this resulted in an hour or so of troubleshooting, and a few minutes of Googling until we discovered the problem.
There is some good news to this though; you're not totally screwed if you accidentally procure the wrong model, you can easily download and upgrade to the correct firmware for an Autonomous AP. This is how it is done:
#1 - Backup existing firmware
First make a backup of your current IOS firmware on the AP, this is so we can quickly revert back to the original firmware in case we brick this device. If you already have a TFTP server installed on your network, you can skip this next step; download and install a free TFTP server from the Internet (I find Solarwinds TFTP Server is a good one to use). Next, make sure you are using a wired connection for this upgrade and avoid performing the upgrade over WIFI; WIFI is subject to a lot of signal interference's, which puts you in a position to brick the AP, so trust in good ol' wired Ethernet!
Just before you do this next step, test that you have connectivity between the Access Point and your TFTP Server via a PING. Now, assuming the PING was successful log into the AP, change to enable mode, and issue the command
archive upload-sw tftp://x.x.x.x/filename
x.x.x.x should be the IP address for your TFTP Server, and filename is the name of the IOS image currently loaded on the AP. After the upload completes with no errors, move onto the next step
#2 - Upload new firmware
Download and copy the new IOS firmware to your TFTP Server, this will be under C:\TFTP-Root if using Solarwinds TFTP. All that is left now is to issue the following command from the AP
archive download-sw /overwrite tftp://x.x.x.x/filename_of_new_image
NOTE: Make sure to include the file extension of the IOS image (e.g: .tar) or running this command will produce an error on the console.
Finally, reload the Access Point to activate the new IOS and run the show version command to confirm the firmware has been properly upgraded. You could also include the /reload option in the above command before the tftp path, to immediately reboot device after the upgrade. Another neat thing to know is that you can perform these upgrades without an outage window (if you omit the /reload option), and when clients are associated to the Access Point; nonetheless, you will have to reload it eventually to complete the upgrade.
Alright, I think that is it for now on the AP vs. LWAP discussion; I hope you stick around to read more wireless stuff, because I guarantee that it's going to get deep!
