LECTURE‐2
HIGH SPEED LAN
HIGH-SPEED LANs
Contents Contents
• Standard Ethernet Standard Ethernet
• Fast Ethernet
• Gigabit Ethernet Gigabit Ethernet
• 10 Gigabit Ethernet
• Fibre Channel
• Fibre Channel
• Wireless LANs
The Emergence of High‐speed LANs
• The speed and computing power of personal computers has continued to enjoy explosive growth. Today’s more powerful platforms support graphics intensive applications and ever platforms support graphics intensive applications and ever more elaborate graphical user interfaces to the operating system.
• MIS organizations have recognized the LAN as a viable and indeed essential computing platform, resulting in the focus on network computing.p g
• Both of these approaches involve the frequent transfer of potentially large volumes of data in a transaction‐oriented
i t
environment.
• The effect of these trends has been to increase the volume of data to be handled over LANs and, because applications are, pp more interactive, to reduce the acceptable delay on data transfers.
Requirements for High‐Speed LANs
• Centralized server farms: In many applications there is a need for
• Centralized server farms: In many applications, there is a need for user or client systems to be able to draw huge amounts of data from multiple centralized servers, called server farms. An example is a color publishing operation in which servers typically contain is a color publishing operation, in which servers typically contain hundreds of gigabytes of image data that must be downloaded to imaging workstations. As the performance of the servers themselves has increased, the bottleneck has shifted to the themselves has increased, the bottleneck has shifted to the network.
• Power workgroups: These groups typically consist of a small number of cooperating users who need to draw massive data number of cooperating users who need to draw massive data files across the network. Examples are a software development group that runs tests on a new software version, or a computer‐
aided design (CAD) company that regularly runs simulations of aided design (CAD) company that regularly runs simulations of new designs. In such cases, large amounts of data are distributed to several workstations, processed, and updated at very high speed for multiple iterations.p p
• High‐speed local backbone: As processing demand grows, LANs proliferate at a site, and high‐speed interconnection is necessary.
High‐Speed LANs
• The most widely used high‐speed LANs today are based onThe most widely used high speed LANs today are based on Ethernet and were developed by the IEEE 802.3 standards committee.
T k ith th h i l l t ki d f
• To keep pace with the changing local networking needs of business, a number of approaches to high speed LAN design have become commercial products. The most important of these are:
are:
• Fast Ethernet and Gigabit Ethernet: The extension of 10‐Mbps CSMA/CD(Standard Ethernet) to higher speeds is a logical
t t b it t d t th i t t i i ti
strategy because it tends to preserve the investment in existing systems.
• Fibre Channel: This standard provides a low‐cost, easilyp y scalable approach for achieving very high data rates in local areas.
•High‐speed wireless LANs:High speed wireless LANs: Wireless LAN technology andWireless LAN technology and standards have at last come of age, and high‐speed standards and products are being introduced.
Characteristics of Some High‐Speed LANs
IEEE 802
• IEEE 802 refers to a family of IEEE standards dealing with local area networks and metropolitan area networks.
• More specifically the IEEE 802 standards are restricted to
• More specifically, the IEEE 802 standards are restricted to networks carrying variable‐size packets.
• The services and protocols specified in IEEE 802 map to the lower two layers (Data Link and Physical) of the seven‐layer OSI networking reference model.
• IEEE 802 splits the OSI Data Link Layer into two sub layers
• IEEE 802 splits the OSI Data Link Layer into two sub‐layers named Logical Link Control (LLC) and Media Access Control (MAC), so that the layers can be listed like this:
Data link layer
‐ LLC Sublayer
‐ MAC Sublayery
Physical layer
IEEE 802 Workgroups
The Generations of Ethernet
The original Ethernet was created in 1976 at Xerox’s Palo Alto Research Center (PARC). Since then, it has gone through four generations.
Standard Ethernet
• In Standard Ethernet the MAC sub layer governs the operation ofIn Standard Ethernet, the MAC sub layer governs the operation of the access method.
• It also frames data received from the upper layer and passes them to the physical layer for encoding
to the physical layer for encoding.
• An Ethernet frame needs a minimum length of 512 bits or 64 bytes and maximum length (without preamble and SFD field) as 1518 b
bytes.
• Standard Ethernet uses 1‐persistent CSMA/CD.
Table : Standard Ethernet implementations
Standard Ethernet
MAC Sublayer
• In Standard Ethernet, the MAC sublayer governs the operation of the access method.
• It also frames data received from the upper layer and passes them to the
h l l f
physical layer for encoding.
Frame Format
• The Ethernet frame contains seven fields: preamble, SFD, DA, SA, length or type of protocol data unit (PDU), upper‐layer data, and the CRC.
• Ethernet does not provide any mechanism for acknowledging received frames, making it what is known as an unreliable medium.
A k l d t t b i l t d t th hi h l
Acknowledgments must be implemented at the higher layers.
Frame Format
Standard Ethernet
• Preamble: A 7‐octet pattern of alternating 0s and 1s used by the receiver to establish bit synchronization.
• Start Frame Delimiter (SFD): The sequence 10101011, which indicates the actual start of the frame and enables the receiver to locate the first bit of the rest of the frame.
• Destination Address (DA): Specifies the station(s) for which the frame is intended It may be a unique physical address a group address or a global intended. It may be a unique physical address, a group address, or a global address.
• Source Address (SA): Specifies the station that sent the frame.
• Length/Type: Length of LLC data field in octets or Ethernet Type field
• Length/Type: Length of LLC data field in octets, or Ethernet Type field, depending on whether the frame conforms to the IEEE 802.3 standard or the earlier Ethernet specification. In either case, the maximum frame size, excluding the Preamble and SFD, is 1518 octets.
• LLC Data: Data unit supplied by LLC
• Pad: Octets added to ensure that the frame is long enough for proper CD operation.
• Frame Check Sequence (FCS): A 32‐bit cyclic redundancy check, based on all fields except preamble, SFD, and FCS.
Frame Length
h h i d i i b h h i i d i
Standard Ethernet
• Ethernet has imposed restrictions on both the minimum and maximum lengths of a frame. The minimum length restriction is required for the correct operation of CSMA/CD.
• An Ethernet frame needs a minimum length of 512 bits or 64 bytes Part of
• An Ethernet frame needs a minimum length of 512 bits or 64 bytes. Part of this length is the header and the trailer.
• If we count 18 bytes of header and trailer, then the minimum length of data from the upper layer is 64 ‐ 18 = 46 bytes
data from the upper layer is 64 18 46 bytes.
• If the upper‐layer packet is less than 46 bytes, padding is added to make up the difference.
• The maximum length of a frame (without preamble and SFD field) as 1518
• The maximum length of a frame (without preamble and SFD field) as 1518 bytes. If we subtract the 18 bytes of header and trailer, the maximum length of the payload is 1500 bytes.
Fast Ethernet
• IEEE created Fast Ethernet under the name 802.3u
• Fast Ethernet is backward‐compatible with Standard Ethernet,p , but it can transmit data 10 times faster at a rate of 100 Mbps.
• The goals of Fast Ethernet can be summarized as follows:
1. Upgrade the data rate to 100 Mbps.
2. Make it compatible with Standard Ethernet.
3 Keep the same 48 bit address 3. Keep the same 48‐bit address.
4. Keep the same frame format.
5. Keep the same minimum and maximum frame lengths.
5. Keep the same minimum and maximum frame lengths.
• The access method is the same (CSMA/CD) for the half‐duplex approach; for full duplex Fast Ethernet, there is no need for CSMA/CD
CSMA/CD.
Fast Ethernet Implementation
• Fast Ethernet can be categorized as either a two wire or a four wire implementation.
• The two wire implementation is called 100Base X which can
• The two wire implementation is called 100Base‐X, which can be either twisted pair cable (100Base‐TX) or fiber optic cable (100Base‐FX).
• The four wire implementation is designed only for twisted pair cable (100Base‐T4).
O f h h f h F E h h i h i
Fast Ethernet Mixed Configuration
• One of the strengths of the Fast Ethernet approach is that it supports a mixture of existing 10‐Mbps LANs and newer 100‐Mbps LANs.
• 100‐Mbps technology can be used as a backbone LAN to support a number of 10‐Mbps hubs.
h h b d h h b h f
• These hubs are in turn connected to switching hubs that conform to 100BASE‐T and that can support both 10‐Mbps and 100‐ Mbps links.
• Additional high‐capacity workstations and servers attach directly to these 10/100 switches. These mixed‐capacity switches are in
t t d t 100 Mb h b i 100 Mb li k
turn connected to 100‐Mbps hubs using 100‐Mbps links.
• The 100‐Mbps hubs provide a building backbone and are also connected to a router that provides connection to an outsidep WAN.
Fast Ethernet Mixed Configuration
Gigabit Ethernet
• In late 1995, the IEEE 802.3z committee formed a High‐Speed Study Group to investigate means for conveying packets in Ethernet format at speeds in the gigabits per second range.
• As more organizations move to 100BASE‐T, putting huge traffic loads on backbone networks, demand for Gigabit Ethernet has intensified.
• Provides speeds of 1000 Mbps (i.e., 1Gbps) for half‐duplex and full‐duplex operation.
Th 1000 Mb ifi i ll f h CSMA/CD f
• The 1000‐Mbps specification calls for the same CSMA/CD frame format and MAC protocol as used in the 10‐Mbps and 100‐Mbps version of IEEE 802.3.
• All Gigabit Ethernet configurations are point‐to‐point!
Gigabit Ethernet Configuration
Gigabit Ethernet Architecture Standard
Media Access Control (MAC) full duplex and/or half duplex
Gigabit Media Independent Interface (GMII) (optional)
full duplex and/or half duplex
(optional) 1000 Base – X PHY
8B/10B auto‐negotiation 1000 Base T
1000 Base T PMA
8B/10B auto‐negotiation PCS
1000 Base‐LX
Fiber optic
1000 Base‐SX
Fiber optic
1000 Base‐CX
Copper
transceiver
Unshielded twisted pair IEEE 802.3ab
p transceiver
p transceiver
pp transceiver Multimode
Fiber
Shieled Copper Cable Single Mode or
Multimode Fiber
IEEE 802.3z
Gigabit Ethernet Technology
Gigabit Ethernet cabling.
1000 BASE SX fiber ‐ short wavelength
f b l l h
1000 BASE LX fiber ‐ long wavelength
1000 BASE CX copper ‐ shielded twisted pair 1000 BASE T copper ‐ unshielded twisted pair
10‐Gbps Ethernet
• The principle driving requirement for 10 Gigabit Ethernet is the increase in Internet and intranet traffic. A number of factors contribute to the explosive growth in both Internet and contribute to the explosive growth in both Internet and intranet traffic:
• An increase in the number of network connections.
• An increase in the connection speed of each end‐station (e.g., 10 Mbps users moving to 100 Mbps, analog 56‐kbps users moving to DSL and cable modems)
moving to DSL and cable modems).
• An increase in the deployment of bandwidth‐intensive applications such as high‐quality video.
• An increase in Web hosting and application hosting traffic.
10‐Gbps Ethernet
• Initially network managers will use 10‐Gbps Ethernet to provide high‐speed, local backbone interconnection between large capacity switches
large‐capacity switches.
• As the demand for bandwidth increases, 10‐Gbps Ethernet will be deployed throughout the entire network and will will be deployed throughout the entire network and will include server farm, backbone, and campus wide connectivity.
• This technology enables Internet service providers (ISPs) and network service providers (NSPs) to create very high‐speed links at a low cost, between co‐located, carrier class switches and routers.
and routers.
( h ) i d f i i l i d
10‐Gbps Ethernet Implementation
10GBASE‐S (short): Designed for 850‐nm transmission on multimode fiber. This medium can achieve distances up to 300 m.
10GBASE‐L (long):( g) Designed for 1310‐nm transmission on single‐g g mode fiber. This medium can achieve distances up to 10 km.
10GBASE‐E (extended): Designed for 1550‐nm transmission on single mode fiber This medium can achieve distances up to 40 km
single‐mode fiber. This medium can achieve distances up to 40 km.
10GBASE‐LX4: Designed for 1310‐nm transmission on single‐mode or multimode fiber. This medium can achieve distances up to 10 km.
10‐Gbps Ethernet Configuration
40 & 100 Gbps Ethernet
• IEEE P802.3ba Task Force states that bandwidth requirements for computing and networking applications are growing at for computing and networking applications are growing at different rates, which necessitates two distinct data rates, 40 Gb/s and 100 Gb/s
• IEEE target for standard completion of 40 GbE & 100 GbE in 2010.
• 40 GbE products shipping today supporting existing fiber plant
• 40 GbE products shipping today supporting existing fiber plant and plan is for 100 GbE to also support 10m copper, 100m MMF and SMF.
• Cost of 40 GbE or 100 GbE is currently 5 – 10 x 10 GbE.
A th d d it f l t
Fibre Channel
• As the speed and memory capacity of personal computers, workstations, and servers have grown, and as applications have become ever more complex with greater reliance on graphics
d id th i t f t d i d li i d t
and video, the requirement for greater speed in delivering data to the processor has grown.
• This requirement affects two methods of data communicationsThis requirement affects two methods of data communications with the processor: I/O channel and network communications.
• An I/O channel is a direct point‐to‐point or multipoint
i ti li k d i tl h d b d d
communications link, predominantly hardware based and designed for high speed over very short distances.
• The I/O channel transfers data between a buffer at the source/ device and a buffer at the destination device, moving only the user contents from one device to another, without regard to the format or meaning of the data.
format or meaning of the data.
Fibre Channel
• ManyMany smallsmall businessesbusinesses andand organizations—fromorganizations from locallocal government, real estate, and insurance agencies to school and university departments—require fast, frequent access to database files
database files.
• Such workgroups would benefit greatly from the speed and reliability of a storage area network with Fibre Channel
it hi switching.
Fibre Channel Features
• Full‐duplex links with two fibers per link
• Performance from 100 Mbps to 800 Mbps on a single line (full duplex 200 Mbps to 1600 Mbps per link)
(full‐duplex 200 Mbps to 1600 Mbps per link)
• Support for distances up to 10 km
• Small connectorsSmall connectors
• High‐capacity utilization with distance insensitivity
• Greater connectivity than existing multi drop channelsGreater connectivity than existing multi drop channels
• Broad availability (i.e., standard components)
• Support for multiple cost/performance levels, from smallpp p /p , systems to supercomputers
• Ability to carry multiple existing interface command sets for existing channel and network protocols
existing channel and network protocols
Fibre Channel Network
• The Fibre Channel network is quite different from the IEEE 802 LANs.q
• Fibre Channel is more like a traditional circuit‐switching or packet‐
switching network, in contrast to the typical shared‐medium LAN.
• Fibre Channel need not be concerned with medium access control issues.
• The key elements of a Fibre Channel network are the end systems,The key elements of a Fibre Channel network are the end systems, called nodes, and the network , which consists of one or more switching elements referred to as a fabric.
• These fabrics are interconnected by point to point links between
• These fabrics are interconnected by point‐to‐point links between ports on the individual nodes and switches.
• Communication consists of the transmission of frames across the
i i li k
point‐to‐point links.
Fibre Channel Physical Media
• Fibre Channel can readily accommodate new transmission
• Fibre Channel can readily accommodate new transmission media and data rates.
• The transmission media options that are available under Fibre Channel include shielded twisted pair, video coaxial cable, and optical fiber.
• Standardized data rates range from 100 Mbps to 3.2 Gbps.Standardized data rates range from 100 Mbps to 3.2 Gbps.
• Point‐to‐point link distances range from 33 m to 10 km.
Wireless LAN
• A wireless LAN or WLAN is a wireless local area network that uses radio waves as its carrier.
• The last link with the users is wireless, to give a network connection to all users in a building or campus, the backbone network usually uses cables.
network usually uses cables.
• Wireless communication is one of the fastest‐growing technologies.
• The demand for connecting devices without the use of cables is increasing everywhere.
• Wireless LANs can be found on college campuses in office
• Wireless LANs can be found on college campuses, in office buildings, and in many public areas.
• IEEE 802.11 defined the specifications for a wireless LAN which covers the physical and data link layers.
Wireless LAN
Single Cell WLAN Multi Cell WLAN
Architecture of WLAN
• The standard defines two kinds of services:
• The standard defines two kinds of services:
¾ The basic service set (BSS) and
¾ The extended service set (ESS).
Basic Service Set (BSS):
• IEEE 802.11 defines the basic service set (BSS) as the building block of a wireless LAN.
block of a wireless LAN.
• A basic service set is made of stationary or mobile wireless stations and a central base station (optional), known as the access point (AP).
access point (AP).
• The BSS without an AP is a stand‐alone network and cannot send data to other BSSs. Such a network is called ad hoc network.
network.
• In this architecture, stations can form a network without the need of an AP; they can locate one another and agree to be part of a BSS
of a BSS.
• A BSS with an AP is referred to as an infrastructure network.
Architecture of WLAN‐BSS
The Extended Service Set (ESS):
Architecture of WLAN
The Extended Service Set (ESS):
• An extended service set (ESS) is made up of two or more BSSs with APs.
I thi th BSS t d th h di t ib ti t
• In this case, the BSSs are connected through a distribution system, which is usually a wired LAN.
• The distribution system connects the APs in the BSSs.
• The ESS uses two types of stations: mobile and stationary.
• The mobile stations are normal stations inside a BSS and the stationary stations are AP stations that are part of a wired LAN.
• When BSSs are connected, the stations within reach of one another can communicate without the use of an AP.
• However, communication between two stations in two differentHowever, communication between two stations in two different BSSs usually occurs via two APs.
• Note that a mobile station can belong to more than one BSS at the same time
same time.
Architecture of WLAN‐ESS
802.11 Protocol Stack
Upper Layers
b b
IEEE 802 11 defines two MAC sub layer protocols:
MAC Sublayer
IEEE 802.11 defines two MAC sub layer protocols:
Distributed Coordination Function(DCF):
• Does not use any kind of central control
/ h h d
• DCF uses CSMA/CA as the access method.
Point Coordination Function (PCF):
• The point coordination function (PCF) is an optional accessp ( ) p method that can be implemented in an infrastructure network (not in an ad hoc network).
• It is implemented on top of the DCF and is used mostly for time‐It is implemented on top of the DCF and is used mostly for time sensitive transmission.
• PCF has a centralized, contention‐free polling access method.
Th AP f lli f t ti th t bl f b i
• The AP performs polling for stations that are capable of being polled.
• The stations are polled one after another, sending any data they have to the AP.
• 802.11 standard specifies three transmission techniques allowed i th h i l l
802.11 Physical Layer
in the physical layer.
802.11 Infrared:
• The Infrared method uses the same technology as televisiongy remote controls.
• Transmit at two speeds of 1Mbps and 2 Mbps.
• Range is 10 to 20 meters and cannot penetrate walls.Range is 10 to 20 meters and cannot penetrate walls.
• Does not work outdoors.
802.11 DSSS:
• Use in short range radio, cordless telephone and microwave oven etc.
• Operate at 1 or 2Mbps and at low power.
802.11 FHSS:
• Uses 2.4Mhz ISM band.
• Over longer distance FHSS offer resistance to multipath fading
• Over longer distance FHSS offer resistance to multipath fading.
• Insensitive to radio interference.
• Lower bandwidth.
802.11a OFDM:
802.11 Physical Layer
• Use Orthogonal Frequency Divisional Multiplexing.
• Operate at 54Mbps and 11 Mbps in wider 5.5 GHz ISM band.
• Uses 52 FDM channels (48 for data; 4 for synchronization)Uses 52 FDM channels (48 for data; 4 for synchronization).
• Encoding is complex.
• More difficulty penetrating walls.
802 11b HR DSSS 802.11b HR‐DSSS:
• High Rate Direct Sequence Spread Spectrum use 11 million chips/ sec to achieve 11 Mbps in 2.4 GHz ISM band
Alth h l th 802 11 i 7 ti t th 11
• Although slower than 802.11a range is 7 times greater than 11a.
• 11b and 11a are incompatible!!
802.11g OFDM:
– An attempt to combine the best of both 802.11a and 802.11b.
– Supports bandwidths up to 54 Mbps.
– Uses 2.4 GHz frequency for greater range.q y g g – Is backward compatible with 802.11b.
Implementations of WLAN
ISM Frequency Bands ISM Frequency Bands
ISM (Industrial, Scientific and Medical) frequency bands:
b d ( )
• 900 MHz band (902 … 928 MHz)
• 2.4 GHz band (2.4 … 2.4835 GHz)
• 5.8 GHz band (5.725 … 5.850 GHz)
Anyone is allowed to use radio equipment for transmitting in these bands (provided specific transmission power limits are not
d d) i h b i i li
exceeded) without obtaining a license.
• Wi‐Fi is a wireless technology that uses radio frequency to transmit data
Wireless Fidelity (Wi‐Fi)
gy q y
through the air.
• Wi‐Fi the short form of Wireless Fidelity is meant to be used generically when referring to any type of 802.11 network, whether generically when referring to any type of 802.11 network, whether 802.11b, 802.11a, 802.11g etc
• The Wireless Ethernet Compatibility Alliance started the Wi‐Fi certification program to ensure that equipment claiming 802 11 certification program to ensure that equipment claiming 802.11 compliance was genuinely interoperable.
• 802.11b was first to reach the marketplace. It is the slowest and least expensive of the three 802 11b transmits at 2 4 GHz and go up to 11 expensive of the three. 802.11b transmits at 2.4 GHz and go up to 11 Mbps.
• 802.11a was next. It operates at 5 GHz and can handle up to 54 Mbps.
f b h ld h ( h
• 802.11g is a mix of both worlds. It operates at 2.4Ghz (giving it the cost advantage of 802.11b) but it has the 54Mbps speed of 802.11a. It is also backward compatible to 802.11b.
• Most Wi‐Fi cards nowadays are capable of all three of these radio technologies.
Wireless Personal Area Network (WPAN)
• Wireless personal area networks (WPANs) are used to convey information over short distances among a private, intimate group of participant devices
group of participant devices.
• Unlike a wireless local area network (WLAN), a connection made through a WPAN involves little or no infrastructure or
di i i h ld id h li k
direct connectivity to the world outside the link.
• This allows small, power‐efficient, inexpensive solutions to be implemented for a wide range of devices.p g
• Two common protocol for WPAN are:
‐ IEEE 802.15.1 WPAN (Bluetooth)
‐ IEEE 802.15.4 LR‐WPAN (ZigBee)
Bluetooth
A id l d WPAN t h l i k Bl t th ( i 1 2
• A widely used WPAN technology is known as Bluetooth (version 1.2 or version 2.0).
• Bluetooth is a wireless LAN technology designed to connect devices of different functions such as telephones notebooks computers (desktop and different functions such as telephones, notebooks, computers (desktop and laptop), cameras, printers, coffee makers, and so on.
• A Bluetooth LAN is an ad hoc network, which means that the network is formed spontaneously; the devices sometimes called gadgets find each formed spontaneously; the devices, sometimes called gadgets, find each other and make a network called a piconet.
• A Bluetooth LAN can even be connected to the Internet if one of the gadgets has this capability
gadgets has this capability.
• A Bluetooth LAN, by nature, cannot be large.
• If there are many gadgets that try to connect, there is chaos.
• Peripheral devices such as a wireless mouse or keyboard can communicate with the computer through this technology.
• The current data rate is 1 Mbps with a 2.4‐GHz bandwidth.
• This means that there is a possibility of interference between the IEEE 802.11b wireless LANs and Bluetooth LANs.
Piconets
• A Bluetooth network is called a piconet, or a small net that can have up to eight stations, one of which is called the primary and the rest are called secondaries.
• All the secondary stations synchronize their clocks and hopping sequence with the primary.
• Note that a piconet can have only one primary station.p y p y
• The communication between the primary and the secondary can be one‐to‐one or one‐to‐many.
Scatternet
• Piconets can be combined to form a scatternet.
• A secondary station in one piconet can be the primary in another piconet.
p
• This station can receive messages from the primary in the first piconet (as a secondary) and, acting as a primary, deliver them to secondaries in the second piconet.p
• A station can be a member of two piconets.
ZigBee
• IEEE 802.15.4 LR‐WPAN is a low rate wireless personal area network which is commonly known as Zig‐Bee.
• ZigBee technology is simpler (and less expensive) than Bluetooth.g gy p p
• The main objectives of an LR‐WPAN like ZigBee are:
‐ ease of installation,
‐ reliable data transfer,
‐ short‐range operation, extremely low cost and
‐ extremely low cost, and
‐ a reasonable battery life,
‐ simple and flexible protocol.
• The raw data rate will be high enough (maximum of 250 kbit/s) to satisfy a set of simple needs such as interactive toys, but is also scalable down to the needs of sensor and automation needs (20 kbit/s( / or below) using wireless communications.
Wi‐MAX
• Worldwide Interoperability for Microwave Access (Wi‐MAX) is a certification mark for products that pass conformity and interoperability tests for the IEEE 802.16 standards.p y
• Use wireless links with microwave or millimeter wave radios at 10‐66 GHz and 802.16a extension to 2‐11 GHz (Mobile extensions: 802.16e)
• Use licensed spectrum (unlicensed too in 802 16a)
• Use licensed spectrum (unlicensed too in 802.16a)
• Metropolitan in scale
• Provide public network service to fee‐paying customers
• Point‐to‐multipoint architecture with rooftop or tower‐mounted antennas.
• Provide efficient transport of heterogeneous traffic supporting QoS
• Provide efficient transport of heterogeneous traffic supporting QoS
• Capable of broadband transmissions at 2‐75 Mbps)
• WiMax is well suited to offer both
Wi‐MAX
WiMax is well suited to offer both fixed and mobile access
• WiMAX is expected to provide fixed , nomadic, portable and, eventually, nomadic, portable and, eventually, mobile wireless broadband connectivity without the need for direct line‐of‐sight (LOS) with a base station.
• In a typical cell radius deployment of three to ten kilometers, WiMAX
b l
systems can be expected to deliver capacity of up to 40 Mbps per channel, for fixed and portable access applications
access applications.
• Mobile network deployments are expected to provide up to 15 Mbps of capacity within a typical cell radius of capacity within a typical cell radius deployment of up to three kilometers.
Wireless Networks Protocols
Network Standard Topology Access Method
Modulation/
Spreading Method
Data Rate Method
WPAN (Bluetooth)
IEEE 802.15.1
Ad-hoc TDMA / TDD Gaussian FSK / FHSS
1 Mbit/s
(Bluetooth v. 1.2) 3 Mbit/s
(Bluetooth v. 2.0) LR-WPAN
(ZigBee)
IEEE 802.15.4
Ad-hoc CSMA/CA Offset-QPSK /
DSSS
250 kbit/s
WLAN (WiFi)
IEEE 802.11 IEEE802.11a IEEE802.11b
Infrastructure (ad hoc also possible)
CSMA/CA DQPSK/ DSSS (802.11b)
64-QAM/OFDM
11 Mbit/s (802.11b) 54 Mbit/s
IEEE802.11g (802.11g) (802.11g)
WMAN (WiMAX)
IEEE 802.16 IEEE 802.16e
Infrastructure TDM/TDMA (down/uplink) TDD or (semi
128-QAM / single carrier 64 QAM /
134 Mbit/s
TDD or (semi- duplex) FDD
64-QAM / OFDM