Mobility Management for Next Generation Wireless Internet

Transcription

1 Mobility Management for Next Generation Wireless Internet Ashutosh Dutta, Ph.D. Senior Scientist NIKSUN Innovation Center Princeton New Jersey,

2 Outline Evolution of mobility protocols A taxonomy of IP-based mobility protocols Handoff optimization Use Case studies Best Current Practices Mobility Modeling, Applicability Conclusions/Future Work. 2

3 A name identifies what you want, An address identifies where it is, and An route identifies a way to get there John Shoch, 1978

4 Evolution of mobility protocols 1 G 2 G 2.5 G 3 G 4 G TACS NMT JTACS NTT AMPS SMR GSM PDC IS-136 IS-95 (A) iden 9.6 kb/s 42 kb/s 48.6 kb/s 9.6 kb/s 24 kb/s GPRS IS-95 (B) EDGE 54 kb/s 236 kb/s 115 kb/s CDMA2000 1X 144 kb/s WCDMA 144 kb/s, 384 kb/s, 2 Mb/s CDMA2000 NX 144 kb/s, 384 kb/s, 2 Mb/s IEEE Mb/s (UL), 360 Mb Mb/s EHSPA 42 Mb/s (DL), 22 Mb/s (UL) UMB 280 Mb/s LTE 50 UL, 100 DL

5 Cellular Access Characteristics Generation System Channel spacing Access type Uplink data rate 1G AMPS 30 khz FDMA N/A TACS 25 khz FDMA N/A NMT 25 khz FDMA N/A NTT 25 khz FDMA N/A 2G GSM 200 khz TDMA 9.6 kb/s PDC 30 khz TDMA 42 kb/s IS khz F/TDMA 48 kb/s IS-95 (A) 1.25 MHz F/CDMA 14.4 kb/s iden 25 khz F/TDMA 24 kb/s 2.5G GPRS 200 khz TDMA 45 kb/s EDGE 200 khz TDMA 236 kb/s IS-95 (B) 1.25 MHz F/CDMA 115 kb/s CDMA2000 1X 1.25 MHz CDMA 144 kb/s 3G UMTS/WCDM 5 MHz CDMA/TD 2 Mb/s A MA CDMA MHz CDMA 2 Mb/s 1xEV-DO 4G LTE 20 MHz OFDMA 50 Mb/s WiMAX 2.5 GHz OFDM 40 Mb/s UMB 5 MHz OFDMA 75 Mb/s

6 Cellular mobility GSM an example AUC HLR VLR AUC Authentication Center BSC Base Station Controller BSS Base Station System BTS Base Transceiver Station EIR Equipment Identity Register HLR Home Location Register MSC - Mobile Switching Center VLR Visitor Location Register EIR BSS MSC BSC 1 BSC 2 BTS A opoa BTS B npoa npoa BTS C npoa BTS D Serving Cell MH Move Target Cell

7 PSTN CDMA2000 An example FA1 Home Agent FA2 AC GMSC PDSN1 L3 PoA PDSN2 L3 PoA HLR VLR PCF1 PCF3 PCF4 PCF2 MSC BSC1 BSC2 BSC3 BSC4 BTS1 L2 PoA BTS3 L2 PoA A B C D E F

8 SAE/LTE - 4G Network S10 Enhanced Packet Core (EPC) S3 MME S11 S6a HSS S7 PCRF Rx+ SGSN S4 Serving Gateway (S-GW) S5 PCEP PDN-GW SGi S6c IP-based IMS network S1-MME S1-U S2a S2b epdg Wn Wm Wx AAA Source enb X2 Target enb X2 E-UTRAN X2 Candidate enb Trusted Non-3GPP (WiFI, WiMAX) UTRAN Untrusted Non-3GPP UE UE UE UE UE

9 What are Characteristics of Next Generation Networks? Heterogeneous networks (CDMA, LTE, WiMAX, ) Access-independent converged IP network Order-of-magnitude increases in bandwidth MIMO, smart antennas Increase in video and other high bandwidth traffic New services and service enabling platforms (e.g., Web 2.0, SON) Large range of cell sizes, coverage areas PAN, LAN, WAN Pico-cellular, micro-cellular, cellular Changes in traffic and traffic patterns Rise in video on demand? Requires good high-bandwidth multicast

10 Mobile Wireless Internet: A Scenario Domain1 WAN Internet Domain2 PSTN gateway UMTS/ CDMA Bluetooth a/b/g WAN a/b/g IPv6 Network PAN LAN LAN Hotspot PSTN Roaming User CH UMTS/CDMA Network Ad Hoc Network

11 Technical issues for mobility management Key Functions Handoff Characteristics May take place between cell, subnet or domain Need to optimize the handoff delay and transient data loss ( e.g., end-todelay up to 200 ms, 3%-5% packet loss, jitter, for real-time VoIP traffic) May use soft-handoff feature of CDMA, but need fast-handoff mechanisms for other technologies (e.g., ) Need to support session based applications for TCP and RTP traffic Configuration Registration Should be configured within few milliseconds Configures IP address and other server parameters (e.g, DNS, SIP server, Gateway) Assist pre-session mobility Hierarchical nature will make the registration faster Helps location management functionality Quality of Service Location Management Need to maintain same QoS during its subnet/domain movement Allow user to maintain same URI irrespective of point of attachment

12 Mobility Taxonomy IP Mobility Personal Terminal Service Session Issues Mobility pattern NetworkTransport Layer Layer MIPv4 Cellular IP HAWAII IDMP MIP-LR MIPV6 ProxyMIPv6 MSOCKS, Migrate msctp Shim Layer HIP Application Layer SIPMM MIP-LR(M) Proxy Systems Optimization Host controlled vs. Mobile Controlled

13 Mobility Illustration in a sample IP-based network Administrative Domain B Registration Agent Authorization Agent Authorization Agent Administrative Domain A Registration Agent Signaling Proxy L2 PoA L2 PoA D L3 PoA Authentication Agent Configuration Agent L3 PoA N1 N2 Backbone Configuration Agent N1- Network 1 (802.11) N2- Network 2 ( CDMA/GPRS) Authentication Agent Layer 3 PoA N2 N1 C Signaling Proxy L3 PoA B A IP ch Corresponding Host Layer 2 PoA Mobile Host Layer PoA ms media interruption h/o delay 900 ms h/o delay 18 s 18 Seconds media interruption 4 Seconds media interruption h/o delay 4 s 13

14 System decomposition of handover process Handover Event P1 P2 P3 P4 P5 P6 Network discovery & selection Network attachment Configuration Security association Binding update Media reroute Channel discover y P11 P13 Server discovery P12 Subnet discovery P21 L2 association Domain Advertisement P22 P23 Router solicitation P31 Identifier acquisition P32 Duplicate Address Detection P33 Address Resolution P41 Authentication (L2 and L3) P42 Key derivation P51 Identifier update P52 Identifier Verification P53 Identifier mapping Binding cache Tunneling P54 P61 Buffering P62 Forwarding P63 P64 Bi-casting/ Multicasting 14

15 Handover: Distributed operation across multiple layers CN Discovery Detection Configuration Security Association p42 Binding Update p52 p54 Media Rerouting p61 Server (Proxy, /HA) p13 p23 p31 p32 p41 p42 p51 p52 p53 p54 p61 p63p64 p62 L3 PoA L2 PoA p12 p22 p11 p21 p11 p12 p13 p21 p22 p23 p31 p31 p31 p32 p32 p33 p33 p41 p41 p42 p42 p42 p51 p51 p51 p52 p61 p61 p62 MN Time

16 Station performing handoff Probe Delay De-authentication Delay Authentication Delay MN (broadcast) Probe Request Probe Response Layer 2 Handoff Delay (802.11) Reassociation Request De-authentication Authentication Request Authentication Response Re-association Request All APs within range on all channels Chan 1 Chan N New AP Discovery Phase Active scanning MN probes AP Passive scanning AP sends beacons periodically Authentication Phase Open authentication Shared authentication i 4 way handshake Association Phase Re-association Delay Re-association Request Re-association Response

17 Layer 2 Discovery Optimization General techniques: Reduce the scanning time Caching of ESSID Use of second interface specific discovery Proactive Discovery (no scanning) Proposed Solutions: Shin et al introduces selective scanning and caching strategy Montavont et al propose periodic scanning Velayos et al propose reduction of beacon interval and performs search in parallel with data transmission Brik et al propose to use a second interface to scan while communicating with the first interface u, k Forte and Schulzrinne Application Layer proactive discovery (e.g., Dutta et al)

18 Optimization techniques for layer 3 configuration Layer 3 address acquisition Proactive caching Duplicate Address Detection Optimistic DAD, Proactive DAD, Passive DAD, Router Assisted DAD NUD (Neighbor Unreachability Detection) Aggressive Router Selection Mobile Node Identifier Acquisition L3 PoA Server Layer 3 Configuration Layer 2 Duplicate Identifier Address Mapping Verification Network Mobile Server MN Node L3 POA Network

19 Security protocols have an impact on the performances of the network End-to-end latency Throughput Handoff delay Main components that affect the performance Authentication/authorization, Key Derivation, Encryption Security related delays may affect all the layers Layer 2 (e.g., i, WEP) Layer 3 (IPSEC/IKE) Upper Layers (e.g., TLS, SRTP) Security Optimization Server Security Association Key Distribution Authentication Encryption Mobile MN Network Server MN Layer 4 Layer 3 Layer 2 L3 POA

20 Optimizing Binding Update Techniques Reduce the latency due to longer binding update when the communicating host is far away Limit the binding update within a domain Proposed Solutions IDMP Regional registration-based Mobile IP HMIPv6 Anchor-based Application Layer B2BUA Proactive Binding Update Binding Update Tunneling Mapping Caching Anchor CN Point Mobile Network Anchor Mobile CN

21 IEEE and MP Enabled Seamless Mobility Deployment Scenario Use Case: Cross layer and multiple interfaces Zone 1 Zone 2 Zone 3 Ne tw or k Ty pe d S SI D/ C ell ID Connect to WLAN N A B S SI D N A Op er at or T- Mo bile Wakeup WLAN Se cu rit y PK M N W EAP- PEA P C ha nn el 1 1 Q o S Y e s Ph ysi cal La yer OF DM Dat a Rat e 40 Mbp s Wakeup WLAN Download over WLAN Shutdown GPS Wi-Fi Zone 4 Zone 5 Zone 6 Airport Shutdown WLAN Link Going Radio State GPS Café Down. GSM Start Download WLAN GS 13 N/ AT NA NA 1 N N/A 9.6 over M WLAN 98 Switch A &Tto WiMAX 9 / kbps Battery level low 9 0 A WiMAX 0 GPS Download over WiMAX Shutdown WLAN Zone 7 Wi-MAX Wi-MAX Zone 9 Network Type Wakeup GPS Zone 8 SSID/ Cell ID Shutdown WiMAX Download over GSM/GPRS Wi-Fi BSSID Operator Security NW EAP Channel QoS Physical Type Layer Data Rate GSM N/A AT&T NA NA 1900 N/A N/A 9.6 Kbps kbps b Airport Café 00:00: Airport Café.11i EAP- 6.11e OFDM 11 Mbps PEAP Courtesy: IEEE chair

22 Handoff Optimization in IMS/MMD Network AAA/HSS Optimization HSS non-sip AS AAA HA S-CSCF SIP AS cdma2000 Non-SIP support non SIP cdma2000 IMS/ MMD I-CSCF E-CSCF Different Domain PCRF DHCP PDSN P-CSCF PCRF DHCP PDSN P-CSCF FTTH /ADSL PCRF DHCP RAN RAN AP P-CSCF Optimized roaming architecture MN P-CSCF Fast handoff 22

23 P-CSCF Fast-handoff Experimental Results Components Optimized Non-Optimized Types of Handoff Reactive Proactive Time in ms PPP Termination Layer 2 Delay PPP Activation MIP-Solicitation MIP-Binding Update DHCP Trigger DHCP Inform SIP Trigger SIP+Security Media Redirection Components Optimized Figure 1: Levels of MMD Optimization Copyright 2007 Telcordia Technologies. All Rights Reserved. 23

24 Media Independent Pre-authentication - Seamless Handoff (a deployment scenario) Information Server Current Network 1 AR AP1 INTERNET TN AA Network 2 MN-CA key CA AR AP2 Network 4 CN Network 3 AR AR CTN AA MN-CA key AP3 CA AP1 Coverage Area Mobile AP 2 & 3 Coverage Area CTN Candidate Target Networks TN Target Network

25 Performance (MPA-Non-MPA) Single I/F MPA No packet loss during pre-authentication, pre-configuration and pro-active handoff before L2 handoff Only 0 packet loss, 4 ms delay during handoff mostly transient data Includes delay due to layer 2, update to delete the tunnel on the router We also reduced the layer 2 delay in hostap Driver L2 delay depends upon driver and chipset MPA Approach non-mpa About 200 packets loss, ~ 4 s during handover Includes standard delay due to layer 2, IP address acquisition, Re-Invite, Authentication/Authorization Could be more if we have firewalls also set up handoff 4 s Non-MPA Approach

26 Optimized handoff delay with MPA (Multiple I/F) a. MIP-based Non-optimized handoff c. MPA and assisted optimized handoff b. SIP-based Non-optimized handoff

27 Scheduling of handover operations Relevant optimization principles Optimal mobility system design SIP-based Fast handoff Mobile VPN Example experimental mobility systems Media Independent Pre-authentication Simultaneous Mobility Optimized handoff In IMS Muti-layer Mobility Multicast fast handoff Potential Target Mobility System Sequential Direct path between CH and MH Limit binding update between CH and MH X X X Maintain Security association between end-points X Anchor-based Forwarding X X Post-handoff triggers X Proactive Pre-handoff triggers X X Proactive network discovery X Proactive authentication X Proactive identifier configuration X Proactive binding update X X Dynamic Buffering X Proactive context transfer X Parallel Discovery of Layer 2 and Layer 3 PoA X 27

28 Dependency analysis among handover operations Handoff Process Precedence Data it depends on Relationship P 11 Channel Discovery P 00 Signal-to-Noise Ratio value P 12 Subnet discovery P 21,P 22 Layer 2 beacon ID L3 router advertisement P 13 Server discovery P 12 Subnet address Default router address P 21 - Layer 2 association P 11 Channel number MAC address Authentication key P 22 - Router solicitation P 21, P 12 Layer 2 binding P 23 - Domain advertisement P 13 Server configuration Router advertisement P 31 Identifier acquisition P 23,P 12 Default gateway Subnet address Server address P 32 Duplicate address detection P 31 ARP Router advertisement P 33 Address resolution P 32, P 31 New identifier P 41 Authentication P 13 Address of authenticator P 42 Key Derivation P 41 PMK (Pairwise Master Key) P 51 Identifier update P 31,P 52 L3 Address Uniqueness of L3 address P 52 Identifier verification P 31 Completion of COTI P 53 Identifier mapping P 51 Updated MN address at CN and HA P 54 Binding cache P 53 New Care-of-address mapping P 61 Tunneling P 51 Tunnel end-point address Identifier address P 62 Forwarding P 51, P 53 New address of the mobile P 63 Buffering P 62, P 51 New identifier acquisition P 64 Multicasting/Bicasting P 51 New identifier acquisition 28

29 Resource usage per mobility events Sub Sub-operations Resource Consumption transitions Bytes exchanged CPU samples Power due to transmission (nano joules) t00 Layer 2 un-reachability test t01 Layer 3 unreachability t11 Discover layer 2 channel t12 Discover layer 3 subnet t13 Discover server t21 Layer 2 association t22 Router solicitation t23 Domain advertisement t31 Identifier acquisition t32 Duplicate address detection t33 Address resolution t41 Layer 2 open authentication t42 Layer 2 EAP t43 Four-way handshake t51 Master key derivation (PMK) t52 Session key derivation (PTK) t61 Identifier update t62 Identifier verification t63 Identifier mapping t64 Binding cache t71 Fast binding update t72 Local caching t81 Tunneling t82 Forwarding t83 Buffering t91 Local id mapping t92 Multicasting/bicasting

30 Modeling of handoff processes An example Resource network capacity p31 p32 p33 Potential Parallel Operation t31 t32 t33 t64 p64 t70 p11 p21 p22 p12 p23 P52 t53 p53 p61 Connected t11 t21 t22 t12 t23 t52 t51 P51 t54 p54 P00 t01 p41 p42 t13 Resource Battery p62 p63 t41 t42 p13 t62 t63 Resource CPU

31 Conclusions/Future Work Cellular mobility typically involves handoff across homogeneous access technology Optimization techniques are carefully engineered to improve the handoff performance IP-based mobility involves movement across access technologies, administrative domains, at multiple layers and involve interaction between multiple protocols Need to define mobility model that will allow to predict the handoff performance and behavioral characteristics such as deadlock based on mobility patterns Define Best Current Practices for Mobility Management for IPbased handoff Several Applications Mobile Cloud Computing, Roaming among carriers, End-to-end QoS 31

32 Several concepts of mobility Terminal mobility, e.g., supported by Mobile IP CH Subnet 2 IP-based Network Subnet 1 MH Typically, you don t just have terminals CH IP-based Network Subnet 2 Users/Persons Subnet 1 Sessions Mobility of users, sessions? MH

33 Personal Mobility: Registration registrar CH IP-based Network Subnet 2 Subnet 1 person@subnet2.org registrar When lady in red moves, she leaves her laptop behind CH IP-based Network Subnet 2 Uses another machine Logs in Subnet 1 User registration performed

34 Personal Mobility: simultaneous registration of multiple bindings CH Subnet 1 Registrar & proxy IP-based Network When lady in red moves, she leaves her laptop behind Uses another machine She can still be located person@subnet1.org person@subnet2.org CH Subnet 1 Subnet 2 person@subnet1.org person@subnet2.org Registrar & proxy IP-based Network Subnet 2

35 Session Mobility INVITE CH Subnet 1 IP-based Network Subnet 2 MH CH IP-based Network Subnet 2 Subnet 1

36 Service Mobility Service Mobility allows a roaming user to get the same view of the network as when he is at home At the time of registration User s service profile is retrieved from the home network The service profile is shared with the responsible entity at home and in the foreign network (wholly or partially) The foreign network provides some of the service required The home network still retains responsibility for other services Examples of entries in the profile of interest may be address book, call handling features, buddy lists, etc.