Chapter 7 Flashcards
Wireless Networking Topologies
Wireless Wide Area Network
Wireless Metropolitan Area Network
Wireless Personal Area Network
Wireless Local Area Network
What is WWAN?
Wireless Wide Area Network Covers a vast geographical area * 2G - GSM (Global System for Mobile) - CDMS (Code Division Multiple Access) * 3G - WCDMA (Wideband CDMA) - HSPA (High Speed Packet Access) * 4G - LTE (Long Term Evolution)
What is WMAN?
Wireless Metropolitan Area Network
Provides RF coverage to a metropolitan area such as a city and the surrounding suburbs
May use WiMAX
What is WPAN?
Wireless Personal Area Network Used within a close proximity Connects tablets, phones, laptops, ear pieces. Uses - Bluetooth - Zigbee - Infra Red Low Bandwidth and Throughput 802.11 WPAN example would be an ad hoc-connection between 2 or more computers
What is WLAN?
Provides networking for building or campus
802.11 is perfect fit for WLAN due to range and speed
Multiple access points connected by a wired network backbone
Provides end users with access network resources and services
Common in SOHO networking
Increasingly common in enterprise networking
802.11 Topologies
Main component is the radio card referred to as a station STA
- 11-2007 Standard defines three service sets
* Basic Service Set (BSS)
* Extended Service Set (ESS)
* Independent Basic Service Set (IBSS)
Mesh Basic Service Set (MBSS)
Minimal Hardware needed for a WLAN
WLAN Client (devices with WLAN interface card) Acess Point (AP) Wired LAN (switch/router)
Basic WLAN components?
Basic Service Set (BSS)
Service Set Identifier (SSID)
Extended Service Set (ESS)
What is SSID?
Service Set Identifier
The logical name used to identify a wireless network
Associated with one or more APs
AP Identification
- BSSID
- MAC address used in BSS
Access Points?
Essentially wireless equivalent of a wired hub
Half-Duplex device
Contend for the Medium just as Stations
Defined as Access Points Stations by the Standard
Types of AP?
Autonomous Access Point - Standalone
Cooperative Access Point - APs with switch like intelligence that work together
Controller-Based Access Point - Thin or lightweight AP that communicates with central controller.
Many APs also support the use of virtual local area networks
2 types of VLANs?
MAC Service Data Unit (MSDU)
Distribution System Services (DSS)
MAC Service Data Unit?
Upper-Layer information contained in the 802.11 wireless data frame
Distribution System Services?
Switch-Like intelligence in AP or WLAN controller that forwards the MSDU
Client Stations?
Radio card that is not a part of an access point
Defined as Non-Access point stations by the Standard
Can be any number of devices
Associated
- When a client station has a layer 2 connection with an access point
Integration Service (IS)
Enables delivery of MSDUs between the Distribution System (DS) and a non-802.11 LAN, via a portal.
Eventual destination of the MSDU payload is usually a wired network
Distribution System (DS)
Defined in 802.11
Interconnects a set of basic service sets via integrated LAN’s creating an Extended Service Set (ESS)
What does DS consist of?
Distribution System Medium (DSM)
Distribution System Services (DSS)
What is WDS?
Wireless Distribution System
A DS that uses the Wireless Medium
Examples of WDS?
Bridges
Repeaters
Wireless Mesh Networks
What is Wireless Backhaul?
A wds can connect access points together using what is referred to as a wireless backhaul
4 MAC Addresses?
SA - Source Address
TA - Transmitter Address
RA - Receiver Address
DA - Destination Address
What is BSA?
Basic Service Area
Physical area of coverage provided by an access point in a BSS
Roaming are of the BSS
Size and shape of BSA varies due to environmental and physical surroundings
Client stations will change data rate based upon received signal strength indicator RSSI thresholds
What is Dynamic Rate Switching?
Process of moving between data rates
BSS vs ESS?
One of more basic service sets connected by a distribution system medium
BSSs typically are deployed with a partial overlap to provide seamless roaming
- Most vendors recommend 15-25% overlap
- Overlap and seamless roaming is not required
ESS - Nomadic Roaming?
Overlap and seamless roaming is not required
Mobility between disjointed cells is referred to as nomadic roaming
ESS - Colocation?
Colocation - Deploying an ESS with multiple access point with total or almost total overlap of coverage
- Intended to increase client capacity
- Different Channel
What is IBSS?
Independent Basic Service Set
Also called
- Peer to Peer network
- Ad hoc network
Clients are configured with the same SSID
Clients communicate using the same channel
What is MBSS?
Mesh Basic Service Set
Ratified in 802.11 - 2011
New service set for 802.11 mesh topology
Uses wireless distribution of network traffic
What is MP?
Mesh Points use Hybrid Wireless Mesh Protocol (HWMP) to select mesh path.
A Mesh Point can also act as an AP in a BSS
One more Mesh Point Portals (MPP) act as gateways to an external network, such as 802.3 wireless backbone
802.11 Configuration Modes
In standard all the radios both ap and client are called STA
Both AP and client stations can be configured in various ways, called Modes
AP Modes?
Vendor Dependent Bridge Mode Workgroup Bridge Mode Repeater Mode Mesh Mode Scanner Mode
Bridge Mode?
AP acts as a wireless bridge
Workgroup Bridge Mode?
AP acts as wireless client for multiple wired devices
Repeater Mode?
AP acts as wireless repeater
Mesh Mode?
AP acts as a wireless backhaul radio for a mesh environment. AP may also act as an AP in a BSS
Scanner Mode?
AP acts as a sensor radio, integrating it into a wireless intrusion detection system (WIDS) architecture
Client Modes?
Infrastructure Mode
Ad Hoc Mode
Infrastructure Mode?
Client will allow communications via an AP
Client can participate in a BSS or an ESS
Ad Hoc Mode?
Client will communicate directly with other clients, without an AP
Client can participate in an IBSS
All transmissions and frame exchanges are peer-to-peer
Cellular vs WLAN?
Cellular
- Outdoor
- Wide area mobility
- Moderate to high mobility
- Moderate bandwidth
- High cost
- Good for everywhere except hotspots
WLAN
- Indoor
- Small area mobility
- Low mobility
- High bandwidth
- Low cost
- Good for hotspots of high bandwidth activity
