Lightweight AP operation

Boots up

Discovery

Find as many controllers as possible.  L2 broadcast - AP's default mode of discovery, but L2 LWAPP transport is no longer supported on controllers.  OTAP - over the air provisioning, Aps that are joined transmit neighbor packets that include the IP of the controller.  The listening AP can provision by listening to this.  Not secure / not really used!?  AP Priming - join the AP to the controller before deployment via command line.  DHCP VID - DHCP option that responds to certain vendor classes and contains a (or list of) controller IP addresses.  DNS - AP looks up CISCO-LWAPP-CONTROLLER (or now CISCO-CAPWAP-CONTROLLER) A record.  The AP polls all of these and compiles a list of controller IP addresses.  The AP then joins the master controller (if configured for the mobility domain) or the least loaded controller (joined APs/Total APs - ie 10/25 will lose over 50/250 because it is a lower percent of usage)  Primed controllers can also be programmed with Primary, Secondary, and Tertiary controller IP addresses taking the guess work out of it.

Join

Join request sent from AP to controller IP which includes the controller type and MAC address, the AP hardware and software version, name, number and type of radios.  The AP's certificate used to initiate a secure tunnel.  Sends a jumbo frame version (1,596) then a 1500 byte frame to see if the network will support jumbo frames.  Controller then sends a join reply that includes Success/Failure and staus  message, the controllers certificate, a tes payload to check for jumbo frames.

Download

The code version on the AP has to match the code version on the controller.  The AP tftps the code version to match the controller and reboots to that new version.  AP downloads its configuration from the controller and applies it.

pop quiz

let me pose a question and see if any of my 14 page views can get it answered.

Why under average conditions is it so necessary to do a planning site survey?

let me clarify a bit: a k12 school wants some wireless for one-to-one or byod. I know I need to be able to support about 25 devices in a room. I know therefore, roughly how many aps I need plus I am going to want TX power low as crap so one AP services one to 1 1/2 rooms. A controller will power the radios down to desired levels so its really just matter of plopping aps in the desired rooms with some pretty damned simple calculations - so what's the hype?

2.5 and 5ghz interference in an average building is pretty minimal, its not like there are busted ass microwaves all lover the place. It is so freakin cost in-effective to place survey cart APs and take readings that wont really do shit.

OMG I found a lead wall in this building, its so crazy I'm glad I spent weeks of travel doing this!

The only thing I got is VARs need to make money - screw VARs. I am so glad to be an independent consultant.

btw: post site surveys for design validation are not in question here - they are a must.

Ya'll know how this goes

WPAN, WLAN, WMAN, WWAN - really.  Damn you people. 

Personal area network is so damn persional 1-10 meters is pretty personal I suppose.  I wish some people wouldn't come within 10 meters of me.

Wireless area network  - duh.

Wireless metro area network - an entire city of wireless I can get on board with.  I wish the area I live would get on the high speed free wireless internet train, not only would it save me some cash  - but it would be such a progressive step for an area not known for it.

Wireless wide area networks - what a great time Verizon, AT&T, etc have deploying mega scale wireless.  (by the way I understand a lot about multiplexing techniques - if someone can make code division multiplexing actually make any sense to me I would appreciate the comment).

Ad-hoc and IBSS (independent basic service set) are that shit that venders turn on all its laptops even when you don't want it.  That way I can connect and share its inter-webs I suppose?  Does anyone really do that?

BSS (basic service set) is the area served by one access point. 

DS distributed system - this is where the access point connects to the wire. 

SSID services set identifier is the name the access point beacons out to his client.  It is 32 characters long and the associates with an mac-address.

BSSID - is the mac-address of the radio interface.

MBSSID - virtual macs are used for multiple seperate SSIDs.

ESS - Extended service set is the network (all APs) that are freely roamed within a singular network.

Repeaters extend the range of wireless, but they kill the throughput.

Bridging is when you connect two WLANs for the purpose of extending a wired network.

  Root devices cannot communicate with other root devices
  Nonroot devices can only communicate to root devices

Mesh networks are when back-hauling of data is used over wireless.  A number of wireless access points connect via a less number of distributed systems.

Here we go...

This marks the start of a new way for me to study for certifications in the networking industry. My hope is that ranting and raving via blog will help me to retain the topics while providing some help to others in the industry.

My traditional method of study is to absorb reading material like a dry sponge and then regurgitate. That has worked well for me in the past but damn if its not boring so I'm spicing it up.

My elevator interview is this: 7 years in the networking industry. I have my bachelors degree (via the previously mentioned study method). I work for a consultant that values knowledge and experience over papers from vendors (I don't mean to devalue certs, but experience does prevail). I have my CCNA and have for some time. I more recently passed my CCNA security; I really didn't need to hit that book hard, I have been bringing up and tearing down vpns for 7 years and I knew the material very well before i opened a book. I find myself to be a jack of all trades (don't good consultants have to be?) but my love (or at least current lust) is wireless. So my pursuit for now is on the CCNA Wireless certification.

Stay tuned....