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Siemens IEEE802.11 Tutorial

Siemens IEEE802.11 Tutorial

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Maximilian Riegel
ICM Networks, Advanced Standardization

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Summary of Contents for Siemens IEEE802.11

  • Page 1 Maximilian Riegel ICM Networks, Advanced Standardization...
  • Page 2 Congress hall, Hotel Semi-public Railway WLAN Corporate Station Plant WLAN Remote Airport Public Access WLAN Home WLAN Campus Coverage in ‘hot-spots’ sufficient. IEEE802.11b meets the expectations for easiness, cost and bandwidth. WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 2 © Siemens, 2002...
  • Page 3 Total PC world market in ‘01: ~ 120 Mio pcs.; > 30 % portable. Source: Frost&Sullivan (2000-03) ’98 ’99 ’00 ’01 ’02 Ruling technology is IEEE802.11b (Wi-Fi) [11Mb/s, 2.4 GHz]. WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 3 © Siemens, 2002...
  • Page 4 Part 3: Physical Layer Part 4: Medium Access Control Part 5: MAC Layer Management Part 6: WLAN Mobility Part 7: WLAN Security Part 8: Public Hotspot Operations Part 9: WLAN – UMTS Interworking WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 4 © Siemens, 2002...
  • Page 5 Part 1: Wireless Internet system architecture Generic Internet network architecture Layering means encapsulation IEEE802.11 – seamless integration into the Internet IP based network architecture Wireless LAN IEEE802.11 basic architecture What is unique about wireless? WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 5...
  • Page 6 Generic Internet network architecture Peer Peer (Client) (Web-Server) Internet/Web Applications http http 802.2 802.2 802.2 802.2 link link link link link link 802.3 802.3 WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 6 © Siemens, 2002...
  • Page 7 TCP segment ip header IP datagramm 802.2 Ethernet ip header tcp header appl. header user data 14 bytes 20 bytes 20 bytes Ethernet frame 64 - 1500 bytes WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 7 © Siemens, 2002...
  • Page 8 IEEE802.11 - seamless integration into the Internet IETF ETSI ATMF WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 8 © Siemens, 2002...
  • Page 9 Time-to-live Protocol Header checksum Source IP Address (32bit) end-to-end, D: Delay Destination IP Address (32 bit) T: Throughput Options (if any) packet-oriented R: Reliability Data “1”= precedent data delivery service WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 9 © Siemens, 2002...
  • Page 10 Wireless LAN IEEE802.11 basic architecture local distribution network internet Netscape apache http http 802.2 802.2 802.2 802.2 802.2 Bluetooth 802.3 802.3 802.3 Bluetooth 802.3 IEEE802.11 Client Access Point Access Router Server WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 10 © Siemens, 2002...
  • Page 11 – “hidden node” problem Mobility – variation in link reliability – battery usage: requires power management – want “seamless” connections Security – no physical boundaries – overlapping LANs Multiple international regulatory requirements WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 11 © Siemens, 2002...
  • Page 12 Part 2: IEEE802.11 Overview Wireless IEEE802.11 Standard IEEE802.11 Configurations IEEE802.11 Architecture Overview IEEE802.11 Protocol Architecture Wireless LAN Standardization WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 12 © Siemens, 2002...
  • Page 13 Provides reliable, efficient wireless data networking Supports peer-to-peer and infrastructure configurations High data rate extension IEEE802.11b with 11 Mbps using existing MAC layer Approved June 1997 802.11b approved September 1999 WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 13 © Siemens, 2002...
  • Page 14 – Access Points and stations – Distribution System interconnects DISTRIBUTION SYSTEM Multiple Cells via Access Points to form a single Network. • extends wireless coverage area BSS-B Station Station Station Station BSS-A WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 14 © Siemens, 2002...
  • Page 15 – works only when cells (using the same frequencies) are not overlapping. Robust against noise and interference (ACK) Hidden Node Problem (RTS/CTS) Mobility (Hand-over mechanism) Security (WEP) Power savings (Sleep intervals) WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 15 © Siemens, 2002...
  • Page 16 – PHY MIB Physical Layer Convergence Protocol (PLCP) – PHY-specific, supports common PHY SAP – provides Clear Channel Assessment signal (carrier sense) Physical Medium Dependent Sublayer (PMD) – modulation and encoding WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 16 © Siemens, 2002...
  • Page 17 802.11h DFS & TPC DFS & TPC 802.11g 802.11a 802.11b 5 GHz 2,4 GHz 2,4 GHz 5 GHz 2,4 GHz 54 Mbit/s 54Mbit/s 2 Mbit/s 54Mbit/s 11Mbit/s Current standardization topics WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 17 © Siemens, 2002...

  • Page 18: Part 3: Physical Layer

    Part 3: Physical layer IEEE802.11 2.4 GHz & 5 GHz Physical Layers Frequency Hopping Spread Spectrum Direct Sequence Spread Spectrum DSSS Transmit Spectrum and Channels IEEE802.11a 5GHz PHY Layer IEEE802.11g: Further Speed Extension for the 2.4 GHz Band Spectrum Designation in the 5GHz range IEEE802.11h: Spectrum and Transmit Power Management...
  • Page 19 Frequency 2.4 GHz High Rate DSSS Ext. (802.11b) – CCK/DQPSK with 5.5/11 Mbps 5 GHz OFDM PHY (802.11a) – Basic parameters identical to HiperLAN2 PHY Frequency – European regulatory issues WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 19 © Siemens, 2002...

  • Page 20: Frequency Hopping Spread Spectrum

    2.4GHz band is 83.5MHz wide (US & Europe) Band is divided into at least 75 channels Each channel is < 1MHz wide Transmitters and receivers hop in unison among channels in a pseudo random manner Power must be filtered to -20db at band edge © Siemens, 2002...

  • Page 21: Direct Sequence Spread Spectrum

    11 chips 1 bit period 11 chips * PRN: Pseudorandom Number Signal Spectrum Receiver baseband signal before matched filter (Correlator) Transmitter baseband signal before spreading Receiver baseband signal after matched filter (De-spread) Transmitter baseband signal after spreading © Siemens, 2002...
  • Page 22 DSSS Transmit Spectrum and Channels Transmit Unfiltered Spectrum Sinx/x Mask 0 dBr -30 dBr -50 dBr fc -22 MHz fc -11 MHz fc +11 MHz fc +22 Mhz WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 22 © Siemens, 2002...
  • Page 23 – OFDM frame duration: 4µs guard interval: 0.8ms – 18MHz channel spacing, 9-10 channels in 200MHz bandwidth Key milestones – First letter ballot by working group from November 1998 meeting – January 1999 joint meeting with ETSI-BRAN © Siemens, 2002...
  • Page 24 PBCC proposal for 22 Mbit/s from Texas Instruments Optional: CCK-OFDM proposal for up to 54 Mbit/s from Intersil Range vs. throughput rate comparison of CCK (802.11b), OFDM( “802.11a” ), PBCC, CCK-OFDM (Batra, Shoemake; Texas Instruments; Doc: 11-01-286r2) WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 24 © Siemens, 2002...
  • Page 25 Spectrum Designation in the 5 GHz range Many European countries are currently opening the 5 GHz range for radio LANs. WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 25 © Siemens, 2002...
  • Page 26 • Stations select transmit powers for each frame according to local and regulatory constraints DFS (Dynamic Frequency Selection) – AP‘s make the decision AP 2 AP 1 – STA‘s provide detailed reports about spectrum usage at their AP 3 locations. WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 26 © Siemens, 2002...
  • Page 27 ‘error proune’ networks. Issues of 5 GHz systems: – Cost: 5 GHz is more expensive than 2.4 GHz – Power: 7dB more transmission power for same distance – Compatibility to IEEE802.11b/g necessary WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 27 © Siemens, 2002...
  • Page 28 Direct Sequence Spread Spectrum OFDM Orthogonal Frequency Division Multiplex Pulse Position Modulation GFSK Gaussian Frequency Shift Keying DBPSK Differential Binary Phase Shift Keying DQPSK Differential Quadrature Phase Shift Keying Complementary Code Keying PBCC Packet Binary Convolutional Coding Quadrature Amplitude Modulation © Siemens, 2002...
  • Page 29 (Start Frame Delimiter; bit synchronization) SIGNAL (rate indication; 1, 2, 5.5, 11 Mbit/s) SERVICE (reserved for future use) LENGTH (number of octets in PSDU) (CCITT CRC-16, protects signal, service, length field) WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 29 © Siemens, 2002...
  • Page 30 „Hidden Node“ Provisions IEEE802.11e: MAC Enhancements for Quality of Service (EDCF) Point Coordination Function (PCF) IEEE802.11e: MAC Enhancements for Quality of Service (HCF) Frame Formats Address Field Description Summary: MAC Protocol Features WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 30 © Siemens, 2002...
  • Page 31 Carrier Sense function to protect against Hidden Nodes. – Duration information is distributed by both transmitter and receiver through separate RTS and CTS Control Frames. Includes fragmentation to cope with different PHY characteristics. WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 31 © Siemens, 2002...
  • Page 32 Efficient Backoff algorithm stable at high loads. – Exponential Backoff window increases for retransmissions. – Backoff timer elapses only when medium is idle. Implement different fixed priority levels WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 32 © Siemens, 2002...
  • Page 33 DIFS, otherwise defer and backoff. Receiver of directed frames to return an ACK immediately when CRC correct. – When no ACK received then retransmit frame after a random backoff (up to maximum limit). WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 33 © Siemens, 2002...
  • Page 34 STA 4’s therefore it begins transmission first Distributed inter-frame deferral Random back-off Distributed inter- frame deferral Station 3 Tx Data Detects channel busy Distributed inter-frame deferral Random back-off Distributed inter- frame deferral Detects channel busy Station 4 © Siemens, 2002...
  • Page 35 STA “A” STA “B” STA“A” Access Point DIFS Data STA A STA “B” cannot detect carrier from STA “A” Next MPDU STA B Time period to defer access is based on duration in CTS Back off after defer © Siemens, 2002...
  • Page 36 • the contention window is a variable window • lower priority queues defer to higher priority queues Mapping to Access Category Transmit Queues Per-queue channel access functions with internal collision resolution WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 36 © Siemens, 2002...

  • Page 37: Point Coordination Function (Pcf)

    Network Allocation Vector (NAV) defers the contention traffic until reset by the last PCF transfer PCF and DCF networks will defer to each other PCF improves the quality of service for time bounded data WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 37 © Siemens, 2002...
  • Page 38 – Caused long delays in standardization process due to its complexity – Recently widely supported „Fast –Track“ proposal to come to a conclusion in TGe • Most complex functions eliminated, streamlined HCF, ... WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 38 © Siemens, 2002...

  • Page 39: Frame Formats

    MAC Header format differs per Type: – Control Frames (several fields are omitted) – Management Frames – Data Frames Includes Sequence Control Field for filtering of duplicate caused by ACK mechanism. WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 39 © Siemens, 2002...
  • Page 40 – Identifies transmitter to address the ACK frame to. Addr 3 = Dependent on To and From DS bits. Addr 4 = Only needed to identify the original source of WDS (Wireless Distribution System) frames. WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 40 © Siemens, 2002...
  • Page 41 – CSMA/CA for broadcast frames Virtual carrier sense function provided to protect against hidden nodes Includes fragmentation to cope with different PHY characteristics Point Coordination Function (PCF) option for time bounded data Frame formats to support multiple configurations and roaming © Siemens, 2002...
  • Page 42 Part 5: MAC layer management Infrastructure Beacon Generation Timing Synchronization Function Scanning Active Scanning Example Power Management Considerations Power Management Approach Power Management Procedure MAC Management Frames WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 42 © Siemens, 2002...
  • Page 43 – subsequent transmissions at expected Beacon Interval – not relative to last Beacon transmission – next Beacon sent at Target Beacon Transmission Time Timestamp contains timer value at transmit time. WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 43 © Siemens, 2002...
  • Page 44 – Timestamp from Beacons used to calibrate local clocks – not required to hear every Beacon to stay in synch – Beacons contain other management information • also used for Power Management, Roaming WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 44 © Siemens, 2002...
  • Page 45 – Find networks simply by listening for Beacons Active Scanning – On each channel • Send a Probe, Wait for a Probe Response Beacon or Probe Response contains information necessary to join new network. WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 45 © Siemens, 2002...
  • Page 46 Steps to Association: Station sends Probe. Access Point C Access Point A APs send Probe Response. Station selects best AP. Station sends Association Request to selected AP. AP sends Association Response. WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 46 © Siemens, 2002...

  • Page 47: Power Management Considerations

    – allows transceiver to be off as much as possible – is transparent to existing protocols – is flexible to support different applications • possible to trade off throughput for battery life WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 47 © Siemens, 2002...
  • Page 48 – stations will wake up to hear a Beacon – TSF timer keeps running when stations are sleeping – synchronization allows extreme low power operation Independent BSS also have Power Management – similar in concept, distributed approach WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 48 © Siemens, 2002...
  • Page 49 – else station sleeps again Broadcast frames are also buffered in AP. – all broadcasts/multicasts are buffered – broadcasts/multicasts are only sent after DTIM. – DTIM interval is a multiple of TIM interval WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 49 © Siemens, 2002...
  • Page 50 – Capability, Status Code, Station ID, Supported Rates Reassociation Request – Capability, Listen Interval, ESSID, Supported Rates, Current AP Address Reassociation Response – Capability, Status Code, Station ID, Supported Rates Disassociation – Reason code WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 50 © Siemens, 2002...
  • Page 51 Part 6: WLAN Mobility IEEE802.11 Ad Hoc Mode IEEE802.11 Infrastructure Mode Mobility inside a WLAN ‚hotspot‘ by link layer functions... IEEE802.11f: Inter-Access Point Protocol (IAPP) WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 51 © Siemens, 2002...
  • Page 52 Independent networking – Use Distributed Coordination Function (DCF) – Forms a Basic Service Set (BSS) – Direct communication between stations – Coverage area limited by the range of individual stations WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 52 © Siemens, 2002...
  • Page 53 BSS (Basic Service Set): a set of stations controlled by a single coordination function Distribution system interconnects multiple cells via access points to form a single network Extends wireless coverage area and enables roaming WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 53 © Siemens, 2002...
  • Page 54 AP else station scans for another AP If AP accepts Reassociation Request normally old AP is notified through Distribution System AP indicates Reassociation to the Distribution System WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 54 © Siemens, 2002...

  • Page 55: Inter-Access Point Protocol (Iapp)

    IEEE802.11f: Inter-Access Point Protocol (IAPP) IAPP defines procedures for – context transfer between APs when stations move – automatic configuration handling of access points Distribution System Server WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 55 © Siemens, 2002...

  • Page 56: Part 7: Wlan Security

    Part 7: WLAN security IEEE802.11 Privacy and Access Control WEP privacy mechanism Shared key authentication Shortcomings of plain WEP security IEEE802.11i: Robust Security Network (RSN) A last word about WLAN security: Summary: MAC Functionality WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 56...
  • Page 57 IEEE802.11 Privacy and Access Control Goal of 802.11 was to provide “Wired Equivalent Privacy” (WEP) – Usable worldwide 802.11 provides for an authentication mechanism – To aid in access control. – Has provisions for “OPEN”, “Shared Key” or proprietary authentication extensions.
  • Page 58 WEP privacy mechanism WEP bit in Frame Control Field indicates WEP used. – Each frame can have a new IV, or IV can be reused for a limited time. WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 58 © Siemens, 2002...

  • Page 59: Shared Key Authentication

    Shared key authentication Station Access Point Secret Key Secret Key Loaded Loaded Locally Locally Shared key authentication requires WEP Key exchange is not specified by IEEE802.11 Only one way authentication © Siemens, 2002...
  • Page 60 – No standardized way to change keys on the fly – Difficult to manage per-user keys for larger groups WEP is no mean to provide security for WLAN access, – … but might be sufficient for casual uses. WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 60 © Siemens, 2002...
  • Page 61 IEEE802.11i: Robust Security Network (RSN) Additional enhancement to existing IEEE802.11 functions: Data privacy mechanism: – TKIP (Temporal Key Integrity Protocol) to enhance RC4-based hardware for higher security requirements, or – WRAP (Wireless Robust Authenticated Protocol) based on AES (Advanced Encryption Standard) and OCB (Offset Codebook) Security association management: –...
  • Page 62 802.11 802.3 802.3 802.3 Bluetooth 802.3 Only VPN technologies (IPSEC, TLS, SSL) will fulfil end-to-end security requirements in public environments. VPN technologies might even be used in corporate WLAN networks. WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 62 © Siemens, 2002...
  • Page 63 Power management support – stations may power themselves down – AP buffering, distributed approach for IBSS Authentication and privacy – Optional support of “Wired Equivalent Privacy” (WEP) – Authentication handshakes defined WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 63 © Siemens, 2002...
  • Page 64 How does it work: Web based access control Web based access control: Enabler for mCommerce and location based services Functions of an integrated access gateway (User Management) Functions of an integrated access gateway (Network services) WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 64 © Siemens, 2002...
  • Page 65 Serving customers in public hot spots... Office Congress hall, Hospital Hotel Railway Station Airport á á á Campus WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 65 © Siemens, 2002...
  • Page 66 Station Plant WLAN Remote Airport Public Access WLAN Home WLAN Campus Most WLAN-enabled notebooks will use DHCP for basic IP configuration. A web-browser will likely be available on all notebooks. WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 66 © Siemens, 2002...
  • Page 67 It is very easy and extremely cheap to become a WLAN operator, but most people did not yet know about it..but wait until they have installed WLAN in their living rooms! WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 67 © Siemens, 2002...
  • Page 68 Selling WLAN access in public hot-spots: Probably to consider … How does your favorite storefront look like? Too much security might hinder your business! WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 68 © Siemens, 2002...
  • Page 69 Using a web page for initial user interaction Free local content services Authentication for Internet access Selection of billing method WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 69 © Siemens, 2002...
  • Page 70 How does it work: Web based access control html RADIUS Username: max.riegel auth client Password: ********** auth WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 70 © Siemens, 2002...
  • Page 71 Due to its limited coverage services delivered by WLAN in hot-spots can easily tailored to their locations. => Operators can start with location based services without huge investments for full geographic coverage. WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 71 © Siemens, 2002...
  • Page 72 – Dynamic subscribtion to additional services – Personalized portal page Real-time accounting based on service, duration and volume – Instant user feedback on portal page or by SMS WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 72 © Siemens, 2002...
  • Page 73 – Loadable user profiles – User-specific routing configuration – Dynamic firewalling rules IP router with NAT engine – Assignment of private addresses for free services – Must allow IPSEC connections WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 73 © Siemens, 2002...
  • Page 74 WLAN – UMTS Interworking: Now widely accepted: ‚loose coupling‘ WLAN loosely coupled to a Mobile Network E.g.: Web based authentication and mobile network security Standards for WLAN – UMTS Interworking WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 74 © Siemens, 2002...
  • Page 75 / somewhere voice, realtime messaging standard web applications best effort precious bandwidth cheap bandwidth carrier grade corporate technology operator driven market driven huge customer base casual users high revenues low revenues WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 75 © Siemens, 2002...
  • Page 76 WLAN as just another radio access technology of UMTS All UMTS services become available over WLAN. but: PLMN is burdened with high bandwidth WLAN traffic. Wi-Fi does not provide all the functionality needed (QoS, security). WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 76 © Siemens, 2002...
  • Page 77 Full competition with open ISP market. Mobile network is carrier of the WLAN traffic. Dynamics of growth may differ. very complex – SIM / USIM cards required – new standards necessary WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 77 © Siemens, 2002...
  • Page 78 Duration [min] 4 min 4 min 5 sec -99,6% based on current IP volume prices of 40¼ *%\WH Time based pricing results in similar costs, e.g. MobileStar Pulsar pricing plan: $0,10/min WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 78 © Siemens, 2002...
  • Page 79 MNOs. There is no time to wait! The WLAN access market is exploding, and WLAN access may be ‘for free’ in many hot-spots in a few years (~3-5 years). WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 79 © Siemens, 2002...
  • Page 80 WLAN – UMTS Interworking: Now widely accepted: ‘loose coupling’ Siemens contributed ‚loose coupling‘ to standardization. MSCS MSCS TDM / ATM / IP PSTN SCP LNP Node B PLMN core Authentication Node B SGSN PLMN access Accounting internet wlan local access network Only Authentication, Authorization and Accounting of WLAN access is performed by the mobile network operator.
  • Page 81 SGSN RADIUS Each hotspot is SS7 endpoint Tight userbase to HLR – SIM cards required – Standalone capability – SGSN or MSC functionality – Flexibility in security at access network WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 81 © Siemens, 2002...
  • Page 82 E.g.: Web based authentication and mobile network security SMS containing Password html RADIUS Username: auth 0172-3456789 client Password: ********** auth mobile network WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 82 © Siemens, 2002...
  • Page 83 Subgroup on “Interworking between HiperLAN/2 and 3 generation cellular and other public systems”. – Detailed architectural description mainly based on the Siemens ‘loose coupling’ principle established – IEEE802.11 and MMAC are now joining this effort. => Wireless Interworking Group (WIG).
  • Page 84 The IEEE 802.11 Handbook – A Designer‘s Companion Bob O‘Hara, Al Patrick; IEEE press, ISBN 0-7381-1855-9 802.11 Wireless Networks – The Definitive Guide Matthew S. Gast; O‘ Reilly, ISBN 0-596-00183-5 WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 84 © Siemens, 2002...

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