2
Outlines
Last lecture
Limitations of QoS in IEEE 802.11
Overview of 802.11e
Traffic Categories
EDCF
HCF
Mobile IP
►Care-of-address,
►MIP Protocol (Discovery, Registration, Tunneling)
►Routing
►Inefficiencies
►MIPv6
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QoS Limitations of 802.11-Wireless Networks-Lecture Slides, Slides of Wireless Networking
This course consist on introduction to wireless communication, evolution of wireless communication systems, medium access techniques, propagation models, error control techniques, cellular systems, emerging networks. This lecture inlcudes: Limitations, Qos, Enhanced, Bursting, Audio, Video, Traffic, Persistence, Factor, Data
Typology: Slides
2011/2012
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2
Outlines
^ Last lecture ^ Limitations of QoS in IEEE 802.11 ^ Overview of 802.11e ^ Traffic Categories ^ EDCF ^ HCF ^ Mobile IP^ ►^ Care-of-address,^ ►^ MIP Protocol (Discovery, Registration, Tunneling)^ ►^ Routing^ ►^ Inefficiencies^ ►^ MIPv
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Last Lecture Types of Attack Goals of 802.11 Security ► Access control, data integrity, confidentality WEP Protocol WEP Authentication Security flaws in original 802.11 ► Physical threat, impersonation, mutual authentication,dictionary attacks, DOS 802.1x Security ► AKM Operations with AS ► AKM operations with PSK IBSS Security model
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Overview of 802.11e Formed in Sep. 1999. TheQoSbaselinedocument was approved in November 2000.The first draft was available in late 2001. Aim to support both IntServ and DiffServ New QoS mechanisms ► EDCF (Enhanced DCF) ► HCF (Hybrid Coordination Function) Backwardly compatible with the DCF and PCF
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^ QoS is realized by introducing traffic categories(TCs) ^ MSDUs are delivered through multiple backoffinstances running as virtual stations^ ►^ Each instance is parameterized with TC specificparameters•^ AIFS, CWmin, CWmax, Persistance factor (PF)^ ►^ For legacy DCF, AIFS=DIFS, PF=2, CWmin < 15^ ►^ CWnew[TC] = (CWold[TC]+1) x PF -
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EDCF (Enhanced DCF) Enhanced DCF Also support bursting Different parameters for different TC/AC Replace DIFS with AIFS (AIFS>DIFS) which is shorterfor audio and video traffic. ► Audio = Video < Data CWmin and CWmax ► Audio < Video < Data Different Persistence Factor (PF) For EDCF, AIFS>=DIFS, PF=1-16, CWmin=0-
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HCF (Hybrid CF) Provides policing and deterministic channelaccess by controlling the channel through theHC (Hybrid Coordinator) Operate in CFP and CP
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^ Detecting the channel as being idle for PIFS,shorter than DIFS, gives the HC high priorityover EDCF ^ HCF model can provide Guaranteed Serviceswith a much higher probability than pure EDCF ^ A signaling protocol can be used to facilitateadmission control and specify service raterequirement
Example^ InternetHome Agent slide by Konidala M. Divyan [3]
Homenetwork A
Network BForeign AgentNetwork C Corresp.Node C Mobile Node
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Mobile IP: Basics, Cont. Correspondent host^ is a host that wants to sendpackets to the mobile host Correspondent host sends packets to the mobilehost’s IP permanent address These packets are routed to the mobile host’shome network Home agent forwards IP packets for mobile host tocurrent care-of address Mobile host sends packets directly tocorrespondent, using permanent home IP assource IP
Internet Home Agent Mobile Node sends Binding Update Home Agent replies with Binding Acknowledgementslide by Konidala M. Divyan [3]
Mobile Node
Network B Network C Network A
Corresp.Node C
Mobile Node registers at its Home Agent
Foreign Agent docsity.com
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Protocol
^ In order to support mobility, MobileIP includes three capabilities:1. Discovery2. Registration3. Tunneling
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Registration
^ Mobile node recognizes that it is on a foreign network,acquires a Care-of-Address and requests its homeagent to forward its data packets to the foreign agent. ^ The process of registration requires 4 steps:1. Mobile node request forwarding service bysending registration request to the foreignagent.
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Registration2. Foreign agent relays this request to the
home agent.3. Home agent accepts or denies the
request and sends registration reply to
the^ foreign agent.
- Foreign agent relays this reply to Mobilenode.