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Fast-handoff Mechanisms for Wireless Internet

Presenter - Ashutosh Dutta 04/12/2005 IRT Group Meeting adutta@research.telcordia.com. Fast-handoff Mechanisms for Wireless Internet. Outline. Motivation Handoff Delay during Wireless Internet Roaming Related Work Multi-Interface/Inter-Technology Handoff Experimental Results

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Fast-handoff Mechanisms for Wireless Internet

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  1. Presenter - Ashutosh Dutta 04/12/2005 IRT Group Meeting adutta@research.telcordia.com Fast-handoff Mechanisms for Wireless Internet

  2. Outline • Motivation • Handoff Delay during Wireless Internet Roaming • Related Work • Multi-Interface/Inter-Technology Handoff • Experimental Results • MIP-based, SIP-based (binding) • Proposed Ways to Optimize the handoff • Multi-interface mobility management • Proactive Handover • SIP-based fast-handoff • Proxy-based handoff for multicast stream

  3. Motivation • It is desirable to limit the jitter, delay and packet loss for VoIP and Streaming traffic • 150 ms end-to-end delay for interactive traffic such as VoIP, 3% packet loss is allowed • Delay due to handoff takes place at several layers • Layer 2 (handoff between AP), Layer 3 (IP address acquisition, configuration) and Media Redirection • Rapid handoff will contribute to overall delay and packet loss • Thus it is essential to reduce the handoff delay introduced at different layers • We propose several mechanisms to reduce the handoff-delay and packet loss

  4. Mobile Wireless Internet: A Scenario Domain1 Internet Domain2 PSTN gateway WAN 802.11a/b/g WAN UMTS/ CDMA IPv6 Network Bluetooth 802.11 a/b/g LAN PSTN Hotspot LAN PAN CH Roaming User UMTS/CDMA Network Ad Hoc Network

  5. SIP-centric Wireless Internet Roaming

  6. Trajectory of a Packet Transmission + Handoff Source Receiver PCM sample Total E-E delay = ∑T i Total Packet Loss = PN – P1 Compressed packet T1 T1 = Encoding Delay T2 = Packetization Delay T3 = Transmission Delay T4 = Handoff Delay T5 = Jitter buffer delay T6 = De-Packetization delay T7 = Decoding Delay VoIP Packet T2 P1 T5 = 0 P1 No handoff Time T3 P1 T5 P1 T4 Lost Packets PN T6 P1 T5 PN P1 T7 T6 PN Handoff VoIP Packet (Application) PN T7

  7. 3  2 1 Handoff Latency DHCP server PPP Dual mode MN Next Access Router VPN GW AP1 AP2 HA/SIP Server CN AAA Server Binds to AP1 Media Layer 2 Security 1 Layer 2 Association Router Advertisement 1- L2 Hand-over Latency Delay 2 – Delay due to IP Address Acquisition and Configuration, authentication, authorization 3 – Binding update and Media Redirection delay DHCP/PPP  2 Stateless Auto-configuration DAD/ARP VPN AAA IGMP/RTCP 3 Binding Update New Media

  8. Sample Delays (L3, L2) L3 Delay SA SF L2 Delay

  9. Mobility Optimization - Related Work • Cellular IP, HAWAII - Micro Mobility • MIP-Regional Registration, Mobile-IP low latency, IDMP • HMIPv6, FMIPv6 (IPv6) • Yokota et al - Link Layer Assisted handoff • Shin et al, Velayos et al - Layer 2 delay reduction • Gwon et al, - Tunneling between FAs, Enhanced Forwarding PAR • DHCP Rapid-Commit, Optimized DAD - Faster IP address acquisition • DFA, MOM (Multicast)

  10. Possible Handover Scenario • Handover between 802.11 and 802.3 networks • Handover between 802.3 and 802.16 networks • Handover between 802.11 and 802.16 networks • Handover between 802.11 and 802.11 networks, across ESSs. • Handover between 802.3 and Cellular networks • Handover between 802.11 and Cellular networks • Handover between 802.16 and Cellular networks

  11. Single Radio Interface Roaming Scenario Provider A Subnet A2(or ESS A2) Subnet B1 (or ESS B1) Subnet A1(or ESS A1) Provider B IEEE 802.11 LAN IEEE 802.11LAN IEEE 802.11LAN Intra-domain Inter-subnet MIH Inter-domain Inter-subnet MIH

  12. Handoff with Single Interface (802.11-802.11) Example Network 2 (802.11) Network 3 Network 1 (802.11) CN R2 R1 AP2 MN DHCP AP1 Assign IP0 to Physical I/F Data MN L2 handover - - DHCP PANA/AAA Assign IP1 to Physical I/F SIP Re-invite with IP1 Packet loss period Data

  13. Multiple Radio Interface Roaming Scenario Cellular Network (CDMA/GPRS) IEEE 802.11LAN IEEE 802.11 LAN Mobile Detects 802.11 may disconnect cellular The mobile detects Cellular starts the connection, WLAN: deactivated WLAN: Activated Cellular: deactivated

  14. 802.11 802.11 Handoff 4 s Figure 1. Single Interface Case (802.11b – 802.11b) – SIP as mobility 802.11 CDMA 802.11 Handoff 17 s Figure 3. Multiple Interface Case (802.11b – CDMA1XRTT) – SIP as mobility 802.11 CDMA 802.11 Handoff 19 s Figure 3. Multiple Interface Case (802.11b – CDMA1XRTT) – MIP as mobility Effect of handoff delay on audio (Non-Optimized)

  15. CH MH RTP1 Time Sec RTP1 59.521 - 10.1.4.162 00.478 RTP2 DRCP DISCOVER 00.652 00.701 DRCP OFFER 00.759 - 10.1.1.130 RTP2 00.938 DRCP ACK 00.949 PANA 00.960 01.031 Re-INVITE (De-REG+REG) (01.049, 01.052) Pr OK 01.151 Pr = 220 ms ACK 01.37 Pr RTP1 01.52 – 10.1.1.130 SIP-based subnet and domain Mobility handoff (Experimental Results) Handoff timing with more granularity Fig 1. Handoff Factors for SIP-based mobility Table 1. subnet/domain handoff Experimental values 3 2 3 

  16. 1 Register 5 Re-INVITE RTP Key Pre-shared key for alice@domain1 Temp. key foralice@domain1 3 302 Moved INVITE 2 Temp. key foralice@domain2 AP 4 INVITE MN MN RTP Key MN Inter-domain Secured Mobility Domain1 (Home network) Domain2 (Foreign network) DIAMETER Server (AAA Foreign) DIAMETER Server (AAA Home) SIP Proxy SIP Proxy DIAMETER Client DIAMETER Client PANA Agent w/Firewall DRCP IPSec PANA Agent w/Firewall DRCP IPSec CH AP Mobile Station PANA Client NAI=alice@domain1

  17. Effect of multilayer security on handoff - SIP-MIP SIP-DRCP-PANA-AAA-IPSEC MIP-DRCP-PANA-AAA-IPSEC Media Interruption – 1.31 sec Media Interruption – ~ 7 s Fig 3b. MIP-based secured Inter-domain mobility handoff timing Fig 3a. MIP-based secured Inter-domain mobility handoff timing

  18. Need for fast-handoff (An example) Control signal CN New data Home Domain Transient data Home SIP Proxy • - Round trip time from • London to Sydney • is 540 ms, 28 hops • London – Berkley • Is 136 ms, 22 hops Public SIP Proxy Public SIP Proxy Transient Data Public SIP Proxy Internet RTP Media after Re-Invite Visited Domain OK ACK Visited Proxy/Outbound SIP server Re-Invite Translator IP2 Register Subnet S2 MN 1 IP0 Subnet S0 MN IP1 Translator Move MN Subnet S1 Move

  19. Fast-handoff mechanisms Key Design Principles: • Limit the signaling due to Intra-domain Mobility • Capture the transient packets in-flight and redirects to the mobile • Obtain IP address proactively and send binding update in the previous network • Make-before-break in multi-interface case • Communicates proactively with CH before the handoff takes place by doing pre-authentication • Have a proxy joins the multicast stream on behalf of the impending client • Methods currently experimented • SIP Registrar and Mobility Proxy-based • Proactive secured handoff (MPA) • Proxy-based handoff for Multicast Streaming • Other SIP-based fast-handoff methods for comparison • Outbound SIP proxy server and mobility proxy • B2BUA and midcom • Multicast Agent

  20. Outbound Server Mobility Proxy Subnet 3 Mobility Proxy Subnet 1 Mobility Proxy Subnet 2 Visited SIP CH Registrar MH Delay Box IP1 Media (1) First move Re-INVITE (2) REGISTER 2’ IP2 (New Address) SIP-CGI (3) Transient Forward Traffic during traffic the move (IP1:p1 ---> IP2:p1) IP2 New traffic Second move Re-INVITE Re-REGISTER IP3 (New Address) SIP-CGI Transient Forward Traffic during traffic the move (IP2:p1 ---> IP3:p1) SIP fast-handoff mechanism using mobility proxy

  21. Heterogeneous Mobility (Host-based) MIP HA Corresponding Host Internet Data, Video Stream, Voice Home Network Testbed Core Network Router/MIP FA Router/MIP FA R R Cellular Network (cdma2000, GPRS) Visited Network A Visited Network B BT AP Ether Bridge 802.11 AP 802.11 AP Visited Network C MIMM MIMM MIMM Laptop or PDA • MIMM provides innovative techniques and algorithms to support • Fast handoff among heterogeneous radio systems • Fast and resource-efficient path quality comparison to allow terminal to pick the • interface that best fits is applications’ QoS needs at the lowest power consumption

  22. Multi-Interface Mobility Management - Results Figure 1: SIP-based Mobility with MIMM Figure 2: Timing for SIP-based Mobility

  23. SIP Mobility (without make-before-break) 802.11-CDMA CN MN RTP 59961 eth0 22.733 RTP 59962 Packets sent at 40 ms interval eth0 22.772 RTP 59963 eth0 22.812 PPP Setup ~16 s WLAN is gone PPP0 is coming up CN – 165.254.55.2 MN – WLAN – eth0 – 10.1.10.2 CDMA – PPP0 – 166.157.12.179 Delay 18 s Re-INVITE ppp0 38.453 Re-INVITE (Re-trans) ppp0 38.965 OK ppp0 39.759 ACK ppp0 39.878 RTP 60402 ppp0 40.769 RTP 60403 ppp0 40.869 Jitter In cellular network Packets sent at 40 ms interval RTP 60404 ppp0 40.969 RTP 60405 ppp0 41.719 RTP 60406 ppp0 41.729

  24. CN MN RTP (28790) (eth0) 16.202 Re_INVITE (IP1) (ppp0) 16.240 RTP (28791) (eth0) 16.242 Re-INVITE (Re-trans) –IP1 (ppp0) 16.750 RTP (28792) (eth0) 16.285 RTP (28793) (eth0) 16.322 RTP (28794) (eth0) 16.362 Re_invite (Re-trans)- IP1 (ppp0) 17.761 RTP (eth0) RTP (eth0) OK (ppp0) 19.639 RTP (eth0) ACK (ppp0) 19.758 RTP (eth0) RTP 28888 Handoff delay (eth0) 20.122 RTP 28889 (ppp0) 20.549 RTP 28890 (ppp0) 20.669 (ppp0) 20.769 20.869 SIP Mobility (MIMM) – Make-before-break (802.11 – CDMA) MN: WLAN - Eth0 – 10.1.10.2 CDMA - PPP0 – 166.157.116.186 CN – 165.254.55.2 • Jitter observed in Cellular • Network • Several Re-INVITE retransmission • in CDMA network • Packets are received in eth0 during • SIP Re-INVITE sequence • No packets are lost during the handoff

  25. Mobility with VPN Internal (protected) External (unprotected) CN External Network 1 External Network N VPN GW x-HA i-HA i-MIP tunnel x-MIP tunnel VPN tunnel Internal Visited Network Internal Home Network DMZ MN MN MN MN • Based on its current location, MN dynamically establishes/changes/terminates tunnels • without changing current standards of IPsec VPN or Mobile IP. • Triple encapsulation tunnel is constructed by: • i-HA (Internal Home Agent): Forwards IP packets to MN’s current internal location • VPN GW: Protects (encrypts and authenticates) IP packets transmitted in external networks • x-HA (External Home Agent): Forwards IP packets to MN’s current external location

  26. i-HA Demonstration Scenario Step 1: MN (at its home network over WLAN) and CN start an application session, then MN starts moving DMZ VPN GW x-HA CN External Network (Cellular) Internal Home Network (WLAN) External (unprotected) Internal (protected) MN MN MN

  27. i-HA Demonstration Scenario Step 2: MN starts preparing alternate path by establishing x-MIP and VPN tunnel over the cellular link, while keeping communication via the home network over WLAN DMZ VPN GW x-HA x-MIP tunnel VPN tunnel CN External Network (Cellular) Internal Home Network (WLAN) External (unprotected) Internal (protected) MN MN MN

  28. i-HA Demonstration Scenario Step 3: MN stops using its home WLAN, starts using cellular and establishes i-MIP tunnel, then continues communication with CN DMZ VPN GW x-HA x-MIP tunnel VPN tunnel i-MIP tunnel CN External Network (Cellular) Internal Home Network (WLAN) External (unprotected) Internal (protected) MN MN MN

  29. Mobile-IP with VPN Experimental Testbed Earth Link DSL Internet MN External Cellular External Hotspot Verizon CDMA 1XRTT Enterprise Firewall 65 66 VPN GW 100 (99) Internal Home (SSID=ITSUMO home) (demo.tari.toshiba.com) 67 i-HA TIA = 111-120 HoA = 70-75 MN X-HA Linux R SIP 2 98 HoA = 210-215 1 10.1.10.0/24 DMZ Network AP Internal Visited .66 - .94 Monitor CH 3 DHCP 205.132.6.64/27 DNS 4 10.1.20.0/24

  30. Step-by-step protocol flow PPP setup over CDMA at SNR (S1) Make-before-break scenario at SNR = S2 Mobile coming back home

  31. Non-make-before-break 802.11 (enterprise) Cellular Packet Loss Due to Non-make-before-break 802.11 (enterprise) Non-make-before-break situation

  32. SUM (make-before-break) 802.11(enterprise) Cellular Out-of-order-packet 802.11(enterprise)

  33. Hotspot 802.11 Cellular External Home 802.11 Home-cellular-Hotspot

  34. Handoff and delay with multiple Interfaces (MIP-VPN) Mobile IP with VPN (a) Packet Transmission Delay (c) Inter-packet departure and arrival delay variation for CBR (Voice) (c) Inter-packet departure and arrival delay variation for VBR (Voice)

  35. VPN traffic in 802.11 VPN traffic in cellular Mobike in cellular Mobike in 802.11 MOBIKE-flow (802.11-Cellular-802.11) MN CN VPN GW RTP Tunnel (RTP) Visited Network 1 (802.11) IP0 – address of 802.11 interface IP1 – address of cellular interface IP0 is primary address Visited Network 2 (Cellular) 44.948 (PPP is up) MOBIKE 45.232 (Last packet on 802.11) MOBIKE Make-before-break No packet loss 45.522 IP1 is primary address 46.312 (First packet on Cellular) 46.432 46.469 28:44.091 MOBIKE 51.894 (802,11 is primary interface) Visited Network 1 (802.11) Packet Loss (Break-before-make) 51.915 MOBIKE 28:52.019 IP0 is primary address MN moves from 802.11 (hotspot) to Cellular to 802.11 (hotspot)

  36. VPN traffic in 802.11 MN CN VPN GW VPN traffic in cellular RTP Mobike in cellular Tunnel (RTP) Visited Network 1 (Cellular) Mobike in 802.11 IP0 – address of 802.11 interface IP1 – address of cellular interface IP0 is primary address Visited Network 2 (802.11) 13.342 ( 802.11 is up) MOBIKE MOBIKE 13.377 13.554 (First packet on 802.11) IP1 is primary address 13.667 (Last packet on cellular) 43.103 (Last packet on 802.11) MOBIKE 47.881 IP0 is primary address Visited Network 1 (Cellular) Packet Loss (No-Break-before-make) MOBIKE 51.519 51.977 MOBIKE-flow (Cellular-802.11-Cellular) No packet loss Out-of-order-packet (make-before-break) MN moves from Cellular to 802.11 (hotspot) to Cellular

  37. AP2 AP1 MN-CA key MN-CA key MN-CA key AA AA AA CA CA CA MPA-assisted Seamless Handoff (a scenario) AR Network 1 CTN Network 2 AR CTN Mobile Current Network TN CTN – Candidate Target Networks TN – Target Network AR AP0 Network 3 AP3 CN Information Service (e.g.,802.21) mechanism can help locate the neighboring network elements in the candidate target networks (CTN)

  38. Functional Components of MPA • Pre-authentication/authorization • Used for establishing a security association (SA) between the mobile and a network to which the mobile may move • L2 pre-authentication can also be enabled based on the established SA • Pre-configuration • Used for establishing contexts specific to the network to which the mobile may move (e.g., nCoA) • The SA created in (1) are used to perform secured configuration procedure • Secured Proactive Handover • Used for sending/receiving IP packets based on the pre-authorized contexts by using the contexts of the current network

  39. GPRS W-CDMA Network L2info cdma2000 GSM AP-ID 802.16 Location L3info 802.11 802.11-SSID longitude Civic-addr Latitude L2Mobility IPv6 L2QoS IPv4 Ciphering L3QoS 802.11r Cost 802.11e standard Auth L2PreAuth Roaming List IPsec 802.11u channel KMP PANA UAM 802.21 IKEv1 IKEv2 KMP L3Mobility BSSID PAA_addr 11i4w Cipher AKM phy EP_addr CT Data_rates AES-CCMP Router_addr Psk CARD WEP Nsp_code MIPv4 ISP_code DHCP_addr Nsp_name 802.1x TKIP L3Preauth HA_addr ISP_name Domain_name Nsp_tariff FA_addr ISP_tariff subnet VPN_server Sip_server

  40. Expected Result Detect new AP in different subnet L3 auth/authz starts L3 handoff starts L2 handoff starts Conventional Method Time L3 handoff completes L2 auth/authz, starts L2 handoff completes L3 auth/authz completes Pre-auth/ Pre-authz starts L2 handoff starts L3 handoff starts Detect new AP MPA Time Pre-auth/ Pre-authz Completes (L2 SAs can be , completed here.) L2 handoff completes L3 handoff completes Critical period (communication interruption can occur)

  41. MN Pre-Authentication SIP mobility is just an example mobility protocol. MPA works for any mobility management protocol CN DATA[CN<->A(X)] AA CA AR Subnet X Subnet Y pre-authentication CN: Correspondent Node MN: Mobile Node AA: Authentication Agent CA: Configuration Agent AR: Access Router

  42. MN Pre-authorization CN DATA[CN<->A(X)] MN-CA key AA CA AR Subnet X Subnet Y pre-authorization CN: Correspondent Node MN: Mobile Node AA: Authentication Agent CA: Configuration Agent AR: Access Router IP address: A(X) Current subnet: X Status: Pre-authentication done Action: pre-authorization

  43. MN-AR key AA CA AR MN Proactive Handover: Initial Phase CN DATA[CN<->A(X)] Subnet X Subnet Y Secure Proactive Handover tunnel establishment procedure CN: Correspondent Node MN: Mobile Node AA: Authentication Agent CA: Configuration Agent AR: Access Router IP address: A(X), A(Y) Current subnet: X Status: Pre-authorization done Action: PH Initiation

  44. MN Proactive Handover: Tunneling Phase CN DATA[CN<->A(X)] MN-AR key Re-Invite[CN<->A(Y)] AA CA AR Subnet X Subnet Y SIP Re-Invite over proactive hanodver tunnel [AR<->A(X)] CN: Correspondent Node MN: Mobile Node AA: Authentication Agent CA: Configuration Agent AR: Access Router IP address: A(X), A(Y) Current subnet: X Status: PH tunnel established Action: SIP Re-Invite

  45. MN Proactive Handover: Completion Phase CN DATA [CN<->A(Y)] over proactive hanover tunnel [AR<->A(X)] AA CA AR Subnet X Subnet Y Proactive handover stop procedure L2 handoff procedure CN: Correspondent Node MN: Mobile Node AA: Authentication Agent CA: Configuration Agent AR: Access Router IP address: A(X), A(Y) Current subnet: X Status: SIP Re-Invite done Action: PH Completion

  46. MPA Communication Flow Candidate Target Network CN CA AR nPoA AA MN oPoA Existing session using oCoA 1. Found CTN Pre-authentication [Authentication Protocol] MN-CA Key 2. High probability to switch to the CTN MN-AR Key Pre-configuration [Configuration Protocol to get nCoA] Pre-configuration [tunnel management protocol to establish PHT 3. Determined to switch to The CTN Secure Proactive Update Phase Binding Update + data Transmission over PHT using nCoA 4. BU completion and Ready to switch Secure proactive handover pre-switching phase [tunnel management protocol to delete PHT] 5. Switching Post Switching Phase: Reassignment of nCoA to its physical Interface New Data using nCoA

  47. MPA Optimization Issues • Network Discovery • Discover the neighboring network elements (e.g., Routers, APs, Authentication Agents) • 802.21 (Information Service), 802.11u, WIEN SG, CARD, DNS/SLP • Proactive IP Address Acquisition • Proactive Duplicate IP address Detection • Proactive Address Resolution • Proactive Tunnel Management • Proactive Mobility Binding Update • Bootstrap Link-layer Security in CTN using L3 Pre-authentication

  48. Protocol Set for the MPA demonstration

  49. Network 2 Network 3 Network 1 AA 10.10.30/24 10.10.20.52/24 PANA Agent 10.10.20.52/24 10.10.40.52/24 Relay/ Client Proxy R1 eth2 eth0 R2 eth0 AR AR IP2 10.10.10/24 DHCP Server DHCP Server CA AP1(Channel 6) SIP with VIC/RAT Application 10.10.10.51 AP2(Channel 9) ITSUMO network CN MN MN Move 10.10.30.25 Experimental Network in the Lab. IP1: 10.10.10.223 IP0: 10.10.40.20 AP1, AP2: Access Point R1, R2: Access Router MN: Mobile Node CN: Correspondent Node IP0, IP1: IP address of MN

  50. Protocol flow for MPA Network 2 (802.11) Network 3 Network 1 (802.11) CN R2 R1 AP2 MN DHCP AP1 Assign IP0 to Physical I/F DHCP Data Assign IP1 to Tunnel I/F PANA (Pre-Authentication and pre-configuration to obtain IP1) Address acquisition Using DHCP relay Tunnel (IP0-IP1) - - SIP Re-invite with IP1 - - Data Deletes Tunnel with PANA Update L2 handover MN Assign IP1 to Physical I/F Packet loss period Data

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