2.4 GHz & 5.0 GHz Frequencies
The IEEE 802.11 standard is the specifications for implementing Wireless Local Area Networks or WLAN for Computers, and handheld devices such as scanners, phones, and tablets that need to communication in the 2.4, 3.6, 5 and 60 GHz frequency bands. These wireless standards are maintained by the IEEE Standards Committee. Wireless standards change rapidly unlink this post.!
AP Radio Frequencies
- A – IEEE 802.11a TX / RX using 1 of 8 channels at 5.0 GHz
- B – IEEE 802.11b TX / RX using 1 of 11 channels at 2.4 GHz
- G – IEEE 802.11g TX / RX using 1 of 11 channels at 2.4 GHz
- N – IEEE 802.11n TX / RX utilizing spatial streaming at 2.4 / 5 GHz
- AC – IEEE 802.11ac TX / RX utilizing spatial streaming at 5 GHz
Encryption TKIP vs. WPA
- Temporal Key Integrity Protocol
- Advanced Encryption Standard
- WEP TKIP is much slower
- WPA AES is faster and more secure
- WPA & WPA2 support Transport Layer Security
- WPA2 was introduced in 2006
- AES ciphers 128 bit, 192 bit, or 256 bit
With WPA2-AES encryption its a more secure, and faster connection than TKIP. Routers, and APs running 802.11n using WPA2-AES clients can see speeds reaching 300 mbps, and even as high 3.46 gbps with perfect conditions and the correct client side supplicant.
802.11n Spatial Streams
The term MIMO or Multiple In, Multiple Out utilizes multiple radio antennas. Basically its like PAgP or LACP but with antennas if you will or at least that’s the way I like to think about it. With MIMO both the transmitter and the receiver share in the responsibility or burden of the throughput when transmitting large amounts of data over the wireless network. At least two streams or chains are required for MIMO functionality. In addition MIMO utilizes a technique called SDM or Spatial Division Multiplexing that takes advantage of the multiple transmit and receive radio chains making it possible to send multiple streams of data simultaneously on the same channel, thereby increasing the data rate and overall throughput.
- 1 x 1 Spatial Stream
- 2 x 2 Spatial Stream
- 3 x 3 Spatial Stream
The IEEE 802.11ac is an evolutionary improvement over the existing IEEE 802.11n standard. One of the major goals of with the 802.11ac standard was to deliver higher levels of performance over that of 802.11n that are comparable to speeds found with today’s Gigabit Ethernet which is incredible when you really consider what that means.
802.11n vs. 802.11ac
- N: Maximum channel bonding 40 MHz
- AC: Increased channel bounding 80 ~ 160 MHz
- N: Maximum Quadrature Amplitude Modulation of 64
- AC: Increased Quadrature Amplitude Modulation of 256
- N: Maximum MIMO or Multiple In Multiple Out spatial streams of 4
- AC: Increased MIMO or Multiple Multiple Out spatial streams of 8
Common Commercial Frequency’s
- Shortwave Radio Station / RF Power 500,000w
- AM Radio Station / RF Power 50,000 w
- Microwave Oven / RF Power ( 2.4 GHz ) 600 ~ 1000w
- Cell Phone / RF Power 200 mW
- Wireless LAN AP ( 2.4 GHz ) 1 – 100Mw
Speeds & Ranges
It goes without saying that the speed and range will vary greatly depending on the surrounding environment so millage may vary greatly. The point being when does the speed begin to decrease due to the overall distance, and the surrounding factors.
- IEEE 802.11a Max 54 Mbps – Range ~ 50 feet
- IEEE 802.11b Max 11 Mbps – Range ~ 100 feet
- IEEE 802.11g Max 54 Mbps – Range ~ 170 feet
- IEEE 802.11n Max 300 Mbps – Range ~ 175 feet
- IEEE 802.11ac Max 1 Gig – Range ~ 100 feet
Wireless Controller Benefits
- Dynamic channel assignment
- Transmit power optimization
- Self healing wireless coverage
- Flexible client roaming
- Dynamic client load balancing
- RF monitoring
- Security management
- Clean Air
CAPWAP
In controller software release 5.2 or later, Cisco lightweight access points use the IETF standard Control and Provisioning of Wireless Access Points protocol CAPWAP in order to communicate between the controller and other lightweight access points on the network. Controller software releases prior to 5.2 use the Lightweight Access Point Protocol LWAPP for these communications.
- RFC: 5415
- Data: UDP 5247
- Control: UDP 5246
If you wanted to capture CAPWAP related traffic from a Switch with a WLC connected to lets say interface Gig0/0/3 you could do the following. Lets also assume that the destination span or capture interface is Gig0/0/5.
Switch#
Switch#configure terminal
Switch(config)#monitor session 1 source interface Gi0/0/3
Switch(config)#monitor session 1 destination interface Gi0/0/5
Switch(config)#end
Switch#
LWAPP
Controls the encrypted traffic and data between the Wireless LAN Controller and Access Point or AP using an X.509 certificate.The control traffic is encapsulated in UDP packet with a source port of 1024 and a destination of port 12223.
HREAP
Hybrid Remote Edge Access Point or HREAP is a wireless solution for remote branch office deployment. It enables or allows for the configuration and control access points in a branch or remote office from the corporate office through a Wide Area Network or WAN link without deploying a controller in each office.
Supplicants
A wireless supplicant is a usually an application provided by a third party vendor that runs on the client device such as a computer, hand scanner or the like. The Supplicant is used for interacting with the wireless network to handle the authentication encryption as well as roaming between Access Points.
Security & Authentication
- LEAP
- PEAP
- WEP
- WPA
- EAPTLS
