2. Wireless Networking
• Refers to any kind of networking that does not
involve cables.
• Transmission system is implemented and
administrated via radio waves.
3. Wireless Networking
Types of Wireless Connections (base on size, range
and speed of data transfer)
1. Wireless PAN(Personal Area Network)
– interconnected devices in small premises
– within reach of a person
Ex. Infrared, Bluetooth
4. Types of Wireless Connections
2. Wireless LAN – interlinking two or more devices
providing a connection to a wider internet through
access point.
3. Wireless MAN – used to connect at high-speed
multiple wireless LANs that are geographically close.
- uses routers, switch
Ex. WiMAX (802.16)
5. Types of Wireless Connections
4. Wireless WAN
- covers large outdoor areas.
- internet
- contains access points, base station
gateways & wireless bridging relays.
6. Wireless Fidelity (WiFi)
WiFi (Wireless Fidelity)
- began in 1997 when IEEE introduced the 802.11
technology that carried higher capacities of data across the
network.
- at first, the price was very high but in 2003, it was made
affordable for the masses.
7. Wireless Fidelity (WiFi)
• WiFi hotspot – wifi location where the users can
connect to the wireless network.
8. Wireless Fidelity (WiFi)
• WiFi technology
802.11b –operates on the range of 2.40 GHz up to
2.4835 GHz
802.11a – has the range of 5.725 GHz to 5.850 GHz
provides up to 54 Mbps speed
802.11g
802.11e – provides excellent streaming quality of
video, audio, voice channels etc.
9. Wireless Network Encryption
• Encryption- protects the real-time traffic of
the network while also preventing unauthorized
access to the data residing on the network's
computers and servers.
• Types of wireless network encryption
• Wired Equivalent Privacy (WEP)
• Wi-Fi Protected Access (WPA and WPA2)
10. Wired Equivalent Privacy
• WEP is the oldest and least secure
• Service Set IDs - the public name for a
wireless network.
14. FCC
• Federal Communications Commission is
the regulatory authority in the United States and
its territories for all forms of
telecommunications including radio, internet,
telephone, television, satellite, cable.
16. Wireless LAN standards and
Certifications
• IETF – Internet Engineering Task Force.
Creates standards protocols for the Internet
including the core protocols of the Internet
Protocol Suite, TCP/IP.
• IEEE – Institute of Electrical and
Electronics Engineers. One of the most
influential standards bodies in the world for
information technology.
17. Wireless LAN standards and
Certifications
• WiFi Alliance – a nonprofit industry
organization was formed in 1999 with the goals of
driving adoption of IEEE 802.11 wireless LAN
standards.
18. Wireless Topologies
• 802.11 Architecture
• STA and AP
• Basic Service Set (BSS)
• Extended Service Set (ESS)
• Distribution System (DS)
• DCF/PCF
19. STA and AP
• STA (mobile station) – the device that
connects to the radio frequency (RF) or wireless
medium and is usually referred to as the
network adapter or network interface card (NIC)
• AP (Access Point) – a device that provides
wireless connection.
20. BSS
• Basic Service Set – a group of STA’s trying to
connect with one another, and a Service Set
Identifier (SSID), which is used to identify an
ESS.
• BSSID – when an AP is offering BSS services, it
will send out a broadcast using radio MAC
address to advertise services it offers.
21. Two types of BSS
• IBSS (Independent BSS) – when there is no
AP in the BSS, more often an ad hoc network.
STA’s within the IBSS will communicate directly
with one another using the same SSID, and a
fully meshed will be formed in order for an STA
to communicate with all STA’s within the IBSS.
23. Types of BSS
• Infrastructure BSS – when there is an AP in
the BSS. All wireless and wired communications
will go through an AP even when STA intends to
send traffic to another STA wirelessly. For
example, when one STA intends to send traffic to
another STA in the BSS, it will first send the
traffic to the AP and then from the AP to the
intended STA.
25. Infrastructure BSS
• As a result, the same traffic is sent over the air
twice and consumes the available medium twice
as opposed to a direct communication from STA
to STA.
26. Extended Service Set (ESS)
• One level above BSS.
• When there are multiple AP and STAs (multiple
BSSes) on the network to form a larger WLAN.
Within an ESS, STA can communicate with STA
from another BSS through APs. The same SSID
will be used.
• Distribution system – the medium that connects
BSSes.
27. Extended Service Set (ESS)
• AP will determine if the traffic received from the
BSS should be forwarded back to the BSS for
another STA, to another AP for another BSS, or
to a destination on the wired network or the
extended network. APs will also communicate
among themselves to determine how to forward
traffic originated from one BSS to another BSS or
from an AP to another AP
29. Distribution System (DS)
• The Distribution System (DS) is the
mechanism specified by 802.11 to be used by AP
to communicate with another AP to exchange
traffic for STAs in BSSes.
30. DCF/PCF
• The 802.11 MAC defines two ways to coordinate
use of the wireless medium: using the
Distributed Coordination Function (DCF)
or the Point Coordination Function (PCF).
31. 802.11 Frame Types
• Management Frames
The 802.11 management frames
enable stations to establish and
maintain communications
32. 802.11 Management Frame Subtypes
• Beacon frame. Beacons are used to allow STA
to locate and identify a BSS.
• Probe request and response frame. STA
sends a probe request frame when it needs to
locate a BSS. An AP or another STA will respond
with a probe response frame after it receives a
probe request frame.
• Authentication frame. An AP authenticates
the identity of an STA before allowing it to
associate to a BSS.
33. 802.11 Management Frame Subtypes
• Deauthentication frame. STA sends a
deauthentication frame to AP or another STA
signaling termination of communications.
• Association request and response
frame Association request frames are used
by STA to request an association with a BSS.
• Reassociation request and response
frame. When an STA moves away from the
associated BSS (AP) and attempts to
associate with another AP using the same
SSID, STA will send a reassociation request
frame to the new AP.
34. 802.11 Management Frame Subtypes
• Disassociation frame. An STA sends a
disassociation frame to BSS to signal
termination of the association
35. Control Frames
• The 802.11 control frames provide delivery of
data frames between STAs.
• Request-to-Send (RTS) frame. 802.11
defines an option mechanism using RTS/CTS to
avoid frame collision.
• Clear-to-Send (CTS) frame. The intended
receiving station, usually an AP, responds to an
RTS with a CTS. The CTS signifies a clearance
for the requesting STA to send a data frame.
36. Control Frames
• Acknowledgement (ACK) frame. The
acknowledgement (ACK) is sent immediately
after receiving a data frame, management frame,
or a Power Save Poll (PS-Poll) frame when the
frame arrives without errors.
• The other three types control frames that are not
discussed here are Power Save Poll (PS-
Poll), Contention-Free End (CF-End), and
CF-End plus ACK (CF-End ACK).
37. Data Frames
• The 802.11 defines a data frame to carry
information from higher layers, such as TCP/IP
type of traffic, in the body of the frame. The
correct technical term is encapsulation.
• simple data, data with Contention-Free
Acknowledgement (CF- ACK), data with
Contention-Free Poll (CF-Poll), data with
CF-ACK and CF-Poll.
38. Wireless Topologies
• AP was originally designed only to connect clients
to a local LAN segment.
• As technology matured and wireless LAN evolved,
bridging and repeater functions were added to AP
to connect LAN segments and clients with
extended ranges.
• AP performing AP-only functionality is typically
referred to as a root-mode AP.
39. Wireless Topologies
• The 802.11 and supplements do not specify
bridge and repeater functionality in the
standards; thus, most wireless bridging and
repeater implementations remain proprietary,
and vendors usually build wireless bridges and
repeaters on top of existing AP functionality.
• A new type of wireless solution called “mesh
network” is emerging.
40. Wireless Repeater
• As a wireless repeater, AP provides connectivity
to AP (in root mode) and clients that are outside
the reach of the root AP. A wireless repeater will
connect to a client through association and
connect to the root AP as a client to the root AP.
42. Wireless Bridges
• APs in bridge mode or dedicated wireless
bridges create a wireless connection by
associating with each other.
• Some vendors offer bridges that act as wireless
bridges and APs simultaneously, so that AP can
connect not only STAs, but also two LAN
segments by wireless medium.
43. Wireless Bridge
• Point-to-Point (PtP). With a point-to-point
topology, a direct wireless bridge link is
established to connect two LAN segments using
a pair of wireless bridges. Usually, directional or
semidirectional antennas are used for creating a
point-to- point connection although omni-
directional antennas can be used to form a
point- to-point connection.
45. Wireless Bridge
• Point-to-Multipoint (PtMP). With a point-
to-multipoint topology, a collection of direct
wireless bridge links connection multiple sites
with a central site tying remote sites together.
47. Mesh Networking
• In mesh networking, all mesh APs can connect
to all other mesh APs in a multipoint-to-
multipoint fashion. Mesh AP is usually referred
to as a node.
49. Adaptive Wireless Path Protocol
(AWPP)
• Cisco has developed the Adaptive Wireless
Path Protocol (AWPP) for the mesh network,
where a dynamic path decision is made based on
link quality and the number of hops.
• The AWPP will determine the best path to
connect clients and MAPs to the network. In the
event of a RAP failure, a backup RAP will be
selected, and the system will converge when the
best path is selected with the new RAP
