... wired network interface port
ã
AP functions
Wireless communications base station
Bridge between the wireless and wired networks
6
Wireless Network Interface Card
(continued)
5
Wireless Network ... ofwireless clients and an AP
ã
Extended Service Set (ESS)
Two or more BSS wireless networks installed in same
area
–
Provides users with uninterrupted mobile access to the
network
ã
All wireless ...
communicate among themselves
Wireless Communications
Wireless LocalArea Networks
4
WLAN Components
ã
Minimal hardware needed for a WLAN
Computer
ISP
Wireless network interface card
Access...
... carrier is of a very narrow bandwidth, which means that its data rate is slow. Figure
9.10 shows the spectrum for an OFDM transmission.
Wireless LocalArea Networks 255
Figure 9.10 Detection of OFDM ... target of this group is to enhance the current 802.11 MAC to provide security improve-
ments.
9.7 Summary
In this chapter we cover the areaofWirelessLocalArea Networks by focusing on a number
of ... requirement for every network, it is an even more
Wireless LocalArea Networks 245
Figure 9.5 Example of frequency reuse
ẵ2
21I
Ê ranfị Ê Slot_time, where i is the number of times the station...
... HomogeneousPlaneWaves 53
3.1.4 InhomogeneousPlaneWaves 53
3.1.5 PhysicsofHomogeneousvs.InhomogeneousPlaneWaves 55
3.2 TheLocalArea 60
3.2.1 DefinitionofaLocalArea 60
3.2.2 ScattererProximity 60
3.2.3 AWidebandPlaneWave ... 3 discusses the basic form that a stochastic localarea channel model must
take. Great care is taken in defining a localarea and a stochastic localarea channel, clearly
stating the assumptions ... ApplicationstoWirelessTechnology 187
vii
THEORY OF STOCHASTIC LOCALAREA CHANNEL
MODELING FOR WIRELESS COMMUNICATIONS
by
Gregory D. Durgin
Final Dissertation submitted to the Faculty of the
Virginia Polytechnic...
... using SIR
ã
Then they shift to FIR speed
Wireless Communications
Low Rate Wireless Personal Area
Networks
2
Objectives
ã
Describe a wireless personal areanetwork (WPAN)
ã
List the different WPAN ... and ZigBee work
ã
Describe the security features of low-rate WPAN
technology
3
What is a WPAN?
ã
Wireless personal areanetwork (WPAN)
Group of technologies that are designed for short-
range ... Security
ã
Security should be of little concern with WPANs
ã
One of the most serious concerns is social
engineering
ã
Designing security in WPANs
Much more difficult task than in other networking
technologies
ã
Public...
... include a set of fields that are present
in the same order in every frame
Wireless# Guide to Wireless Communications 15
802.15.3 Network Topology (continued)
Wireless# Guide to Wireless Communications ... corrected
–
Also called error correction (FEC)
Wireless# Guide to Wireless Communications 26
Mesh Networking (802.15.5)
(continued)
Wireless# Guide to Wireless Communications 28
How UWB Works
ã
UWB ... division multiplexing (OFDM)
ã
Commonly referred to as MB-OFDM
ã
Frequency band is divided into five groups containing a
total of 14 frequency bands
Wireless# Guide to Wireless Communications...
... have a radius of up to 35 miles (56
kilometers)
2
Objectives
ã
Explain why wireless metropolitan area networks
(WMANs) are needed
ã
Describe the components and modes of operation of
a WMAN
ã
List ... a WMAN?
ã
Wireless metropolitan area networks (WMANs)
Provide wireless connectivity across a substantial
geographical area such as a large city
ã
WMANs primary goals
Extend wired networks beyond ... same network
ã
WiMAX MAC layer makes it easy for carriers to
deploy the network
ã
Range of a WiMAX network is measured in miles
ã
Cellular phone operators can easily incorporate
WiMAX networks
...
... for a stationary user
ã
3G network technologies
CDMA2000 1xEVDO
ã
For 2.5G CDMA2000 1xRTT networks
25
Binary Runtime Environment for
Wireless (BREW)
ã
BREW is a thin software environment
Very ...
(continued)
ã
Short Message Services (SMS)
One of the most widely used applications
–
Allows for the delivery of short, text-based messages
between wireless devices
ã
Messages are limited to about ... (2.5G)
Interim step between 2G and 3G
–
Operates at a maximum speed of 384 Kbps
–
2.5G networks are packet-switched
Advantages of packet switching
ã
Much more efficient
Can handle more transmissions...
... nhất được nhận dạng bởi thiết bị hai đầu.
5.4 CÔNG NGHỆ VLAN:
VLAN là viết tắt của Virtual LocalAreaNetwork hay còn gọi là mạng LAN
ảo. Một VLAN được định nghĩa là một nhóm logic các thiết ... hình native VLAN thì
phải cấu hình ở giao diện vật lý.
CHƯƠNG II
LÝ THUYẾT VỀ MẠNG
WAN (WIDE AREA NETWORK)
I. KHÁI NIỆM :
Là mạng được thiết lập để liên kết các máy tính của hai hay nhiều khu ... trí rất xa nhau, ví dụ như
những quốc gia khác nhau, thì khi đó ta có mạng diện rộng WAN(Wide Area
Network)
Trang
NGUYỄN ĐÌNH CÔNG – 36CLTH
2929
V./. CÁC CÔNG NGHỆ MẠNG LAN :
5.1. CÔNG NGHỆ CHUYỂN...
... Trunking: Off, Encapsulation type: Unknown
SwitchA#show trunk b
DISL state: Off, Trunking: Off, Encapsulation type: Unknown
SwitchA#
Note that "Off" is the default DISL state. "Off" ... Page 1 of 17
http://www.certificationzone.com/studyguides /?Issue=34&IssueDate=04-01-2001&CP= 11/06/01
Date of Issue: 04-01-2001
CCNA Layer 2 Switching - Virtual Local
Area Networks
Lab ... Enterprise edition software. The Cisco IOS software CLI is not
available if the switch has been configured with the Standard edition software.
While it is possible to complete most of this lab using...
... installation of Ethernet networks, a change was
made to the network topology
.
Networks were converted from
coaxial cable to twisted pair cabling by introducing a new device
into the network. That ... an IP network or
subnet.
In most practical networks, all devices in a small business or enterprise network are not located on the same
Ethernet network broadcast domain.
W
e separate the networks ... the history of Ethernet, the virtual LAN is a recent addition. The VLAN was introduced to solve a number of
networking issues. In this whitepaper you will learn about the evolution of Ethernet,...
... wave
of an Ethernet signal is made of many different sine waves,
each important to creating the shape of the square wave.
Ethernet Signal Preservation
In Factory-Terminated Patch Cords for LocalArea ... wave.
Figure 1: The square wave of an Ethernet signal.
Figure 3: Sine waves of varying frequencies.
The philosophy of the TrueNet system is to eliminate the
root causes of poor throughput in structured ... square wave is made up of
the sum of many sine waves. If anything should happen to
the energy in one or more of those sine waves as they travel
down the wire, the shape of the square wave can...