2. IP Mobility Dr. Eng. Amr T. Abdel-Hamid NETW 903 Winter 2010 Networks & Services

3. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Mobility and Standard IP Routing  IP assumes end hosts are in fixed physical locations  What happens if we move a host between networks?  IP addresses enable IP routing algorithms to get packets to the c orrect network  Each IP address has network part and host part  This keeps host specific information out of routers  DHCP is used to get packets to end hosts in networks  This still assumes a fixed end host  What if a user wants to roam between networks?  Mobile users don’t want to know that they are moving between netwo rks  Why can’t mobile users change IP when running an application?

4. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks No mobility High mobility mobile wireless user, using same access point mobile user, passing through m ultiple access point while maint aining ongoing connections (lik e cell phone) mobile user, connecting/ dis connecting from network usi ng DHCP. Moderate mobility Mobility Classification Protocols

5. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Mobility Micro Macro Global Intra-subnet Intra-domain Inter-domain Cellular IP (1998) TMIP (2001) TeleMIP (2000) Hierarchical MIP ( 1996) Hawaii (1999) Dynamic Mobility Agent (2000) HMIPv6 (2001) MIP (1996) MIPv6 (2001) Time (evolut ionary path) Mobility Classification Protocols

6. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Wirelss access networks and mobile IP

7. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Mobile IP  Mobile IP was developed as a means for transparently deali ng with problems of mobile users  Enables hosts to stay connected to the Internet regardless of their lo cation  Enables hosts to be tracked without needing to change their IP addre ss  Requires no changes to software of non-mobile hosts/routers  Requires addition of some infrastructure  Has no geographical limitations  Requires no modifications to IP addresses or IP address format  Supports security  Could be even more important than physically connected routing

8. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Mobile IP Entities  Mobile Node (MN)  The entity that may change its point of attachment from network to network in the Internet  Detects it has moved and registers with “best” FA  Assigned a permanent IP called its home address to which other hosts send packets regardless of MN’s location  Since this IP doesn’t change it can be used by long-lived applicatio ns as MN’s location changes  Home Agent (HA)  This is router with additional functionality  Located on home network of MN  Does mobility binding of MN’s IP with its COA  Forwards packets to appropriate network when MN is away  Does this through encapsulation

9. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Mobile IP Entities contd.  Foreign Agent (FA)  Another router with enhanced functionality  If MN is away from HA the it uses an FA to send/receive data to/fr om HA  Advertises itself periodically  Forward’s MN’s registration request  Decapsulates messages for delivery to MN  Care-of-address (COA)  Address which identifies MN’s current location  Sent by FA to HA when MN attaches  Usually the IP address of the FA  Correspondent Node (CN)  End host to which MN is corresponding (eg. a web server)

10. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks 22.10.20 07 9 Mobile IP (MIPv4) Internet Home Agent R R R Home network A Foreign Network B Network C Correspondent Node C Foreign Agent

11. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks 22.10.20 07 10 Step1:Agent Discovery R bit: registration re quired H,F bits: home or fore ign agent B bit: Busy M, G bit: Minimal, Gener ic encapsulation V bit: Van Jacob Header compression Agent Advertise ment Agent Solicitati on Type=10| code| checksum reserved With TTL=1

12. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Step 2: Registration Internet Home Agent Mobile Node R   R R Foreign Network B Network C Home Network A Correspondent Node C Foreign Agent  Foreign agent sends Binding Update  Home Agent replies with Binding Acknowledgement

13. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Step 2: Registration (Example) Home address Care-of addressLifetime (sec) 128.119.40.18679.129.13.2150 ……… Mobility binding table at Home Agent Home addressHome agent address Media addressLifetime 128.119.40.186 128.119.40.7 00-56-80-56-A1-E1 150 Visitor List at Foreign Agent

14. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Step 2: Registration (Example) visited network: 79.129.13/24 home agent HA: 128.119.40.7 foreign agent COA: 79.129.13.2 COA:79.129.13.2 ….…. ICMP agent adv. Mobile node MA: 128.119.40.186 registration req. COA:79.129.13.2 HA: 128.119.40.7 MA: 128.119.40.186 Lifetime: 9999 identification:714 ….…. registration req. COA:79.129.13.2 HA: 128.119.40.7 MA: 128.119.40.186 Lifetime: 9999 identification: 714 encapsulation format ….…. registration reply HA: 128.119.40.7 MA: 128.119.40.186 Lifetime: 4999 Identification: 714 encapsulation format ….…. registration reply HA: 128.119.40.7 MA: 128.119.40.186 Lifetime: 4999 Identification: 714 ….…. time

15. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Reg. request format Reg. reply format Step 2: Registration Minimal Encapsulation format

16. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Step 3: Indirect Routing via Tunneling Permanent addres s: 128.119.40.186 Care-of address: 79.129.13.2 dest: 128.119.40.186 packet sent by correspondent dest: 79.129.13.2 dest: 128.119.40.186 packet sent by home agent to foreign a gent: a packet within a packet (Tunnel) dest: 128.119.40.186 foreign-agent-to-mobile pack et Home agent broadcasts ARP request which causes all nodes in the Home network to update their ARP cache s to map the mobile nodes IP address to the home age nts link level address. mobile replies directly to correspondent

17. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks RO(Operation 1: Binding Cache) Internet home network visited network 4 2 1 First Packet to mobile host Binding update CN 3

18. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Internet home network visited network 4 5 3 CN Subsequent packets to the mo bile host RO (Operation 1: Binding Cache)

19. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks RO(Operation 2: Smooth handoff)

20. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Internet foreign network visited at sessio n start FA 2 New FA 1 5 CN New Foreign network home network Binding Update 4 RO (Operation 2: Smooth handoff) Binding U pdate Binding Warning 3

21. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks 20  If the FA and Mobile node share a security association, the FA can cho ose the new registration key  If the HA and the FA share a security association, the HA can choose th e new registration key  If the FA has a Public key, the HA can supply a new registration key  If the Mobile node includes its’ Public key in the registration request, the FA can choose the new registration key  The Mobile node and its’ FA can execute a D-H key exchange protocol t o get a new registration key RO (Operation 3: Establishing Registration keys)

22. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks RO(Operation 4: Special Tunnels) Internet FA1 rebooted FA2 3 CN New Foreign network home network Binding Update 4 Special T unnel 2 1 No visitor list or Binding cac he [(CN,FA1), (CN, MH), … ] [(FA1, MH), (CN, MH), … ] same 5

23. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Ingress Filtering home agent correspondent host Correspondent, home agent on same network. Packet from mobile host is deemed "topologically incorrect" Routers which see packets coming from a direction from which they would not have routed the source address are dropped (external domain)

24. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Reverse Tunneling Internet HA FA MH CN COA Home Network Pro: Firewall and Ingress Filtering problems removed Con: Lengthy Routing Path (double triangular), increase in congestion MH cannot make a tunnel directly to C N

25. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Route Optimization Messages Binding warning Binding update Binding request Binding Acknowledgemen t

26. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks 22.10.20 07 25 Problems with MIPv4  Authentication with FA is difficult as it belongs to another organization  Guaranteeing QoS to a flow of packets is difficult because of triangulatio n and tunneling.  Triangular routing and frequent handoffs cause significant end-to-end de lay (Micro-mobility helps a bit)  High signaling load on HA if mobile node moves frequently.  To support Global mobility, all routers should have FA and HA functional ity (solved with a reduced scope in Macro-mobility).  For some applications, it may be important to track the location of mobile nodes : causes huge power and signaling load.  Paging (the maintenance of information when the node is idle) is not sup ported by MIP. ( Paging is a procedure that allows a wireless system to search for an idle mobile host when there is a message destined to it, such that the mobile use r does not need to register its precise location to the system whenever it moves )  User perceptions of Internet reliability.  If FQDN of the Mobile node has many IP addresses, which one to choos e?

27. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks 22.10.20 07 26 Hierarchical Mobile IP (HMIP) Internet Localizing Registration s HA FA 1 FA 2 FA 3 FA 4 FA 5 FA 6 MH@FA 1 MH@FA 2 MH@FA 4 MH@VL Lineage MH@FA 5 Common ancesto r = FA 2 (nearest) Common ancesto r = FA 1 (nearest) MH@FA 3 MH@FA 6 MH@VL

28. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Mobility using Session Initiation Protocol ( SIP)  A Signaling Protocol  Originally used for negotiating media sessions be tween end systems  Media may go through different networks  Other uses: Conferencing, VoIP, Instant Messagi ng etc.  Elements (SIP user agent, Servers, and Gateway s)  Addressing (URLs) e.g. name@domain and sup ports both Internet and PSTN address

29. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks SIP Session Setup Example 200 OK ACK INVITE sip:abc@uunet.com host.wcom.comsip.uunet.com SIP User Agent Client SIP User Agent Server BYE 200 OK Media Stream

30. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks SIP Proxy Server Example server.aol.com 200 OK BYE 200 OK INVITE sip:abc@aol.com host.aol.com 200 OK ACK INVITE sip:abc@uunet.com sip.uunet.com Media Stream SIP User Agent Client SIP User Agent Server SIP Proxy Server

31. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks SIP Redirect Server Example 302 Moved sip:abc@uunet.com ACK Media Stream INVITE sip:abc@aol.com 180 Ringing ACK INVITE sip:abc@uunet.com REGISTER abc@uunet.com host.aol.com 200 OK server.aol.com 200 OK SIP User Agent Client SIP Redirect Server SIP User Agent Server

32. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Mobility using SIP SIP Redirect Server SIP Proxy Server Foreign Netwo rk Mobile Host Home Network Corresponding Host 12 3 6 4 5 1 INVITE 2 302 moved temporarily 3, 4 INVITE 5, 6 OK 7 Data Benefits: Global mobility, No tunneling, No change to routing 7

33. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Cellular IP  Cellular IP represents a new mobil e host protocol  simple, and flexible protocol for hig hly mobile hosts  CIP supports local mobility & effici ently internet works with Mobile IP CIP Gateway Internet BS MN1 data/control packets from MN 1 Mobile IP BS MN2 packets from MN2 to MN 1 A gateway (GW) acts as foreign agent for ea ch domain (all MNs use GW address as COA) Within the domain: host-based routing routing cache entries using soft-state routing cache updated by upstream pa ckets separate paging cache for in-active nod es  routers within domain have to be CIP awa re

34. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Wireless Access network Model MH B D Internet with Mobile IP R R A C E F G Home agent of MH Gateway Beacon signal

35. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Packets will be first routed to the host's home agent and then tunneled to the gateway The gateway "detunnels'' packets and forwards them toward base stations Packets transmitted by mobile hosts are first routed to the gateway and from there on to the Internet MOBILE IP CELLULAR IP

36. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Cellular IP Paging  Idle mobile hosts that receive a packet move from idle to active state, start their active-state-timer and immediately transmit a route-update packet.  This ensures that routing cache mappings are establishe d quickly

37. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Mobile host state machine

38. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Efficient Location Management Two parallel structures of mappings (PC &RC) 1 - idle MH keeps PC upto-date 2 - PC mappings used to find the loc of idle MH 3 - maintains RC mappings until actively connected 4 - routing of data packets to MH XXX PCRC Service Area Mobile Host 1 2 3 4 PAGING & ROUTING

39. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Illustration of Paging MH B D R A C E F G Internet with Mobile IP GW X Paging-update packets create mappings in PCs X : from GX : from C Paging-update I don’t have a PC

40. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks PCs updated for a moving host X : from GX : from C B D R A C E F G Internet with Mobile IP GW X X : from F X : from F,G G times out MH No change in PC at A

41. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks X : from FX : from C B D R A C E F G Internet with Mobile IP GW MH X Paging packets are routed to the mobil e host by PCs X

42. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Handoff X : from D X : from D, E X : from E X : from C E B D R A C F G Internet with Mobile IP GW X X : from F

43. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Paging & Routing caches

44. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Handoff  Cellular IP handoff  Hard handoff  Semi-soft handoff  Hard handoff  During the Handoff Latency the downlink packets are l ost.  Semi-soft handoff  Improvement over Hard Handoff

45. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Hard-Handoff 2.MN send Route Update Packet to G W 3.BSs are refresh RS 4.GW send data packets to MN 1.MN From Old BS to New BS

46. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Semi soft-Handoff  Improvement over Hard Handoff ; NO packet loss & smo oth handoff.  Need for buffering at the cross over point :For smooth ha ndoff

47. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Compare Mobile IP & Cellular IP  Location management  Mobile IP: Care-of-address  Cellular IP: paging update packet  Routing  Mobile IP: registration  Cellular IP: routing cache  Handoff  Mobile IP: encapsulation, triangle routing  Cellular IP: routing cache

48. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks 22.10.20 07 Handoff-Aware Wireless Access Internet Infrastructure (HAWAII) Internet Home domain r oot router IP tunnel Foreign d omain roo t router CN AP MH Router at Level 1 DHCP S erver 1 Co-located COA 2 Registering with HA 3 4 5 New AP answers reg. req AP Updates routers IP Routing

49. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks 48 What is HIP?  HIP = Host Identity Protocol  A proposal to separate identifier from locator at the network lay er of the TCP/IP stack  A new name space of public keys  A protocol for discovering and authenticating bindings between p ublic keys and IP addresses  Secured using signatures and keyed hashes

50. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks 49  A new Name Space of Host Identifiers (HI)  Public crypto keys!  Presented as 128-bit long hash values, Host ID Tags (HIT)  Sockets bound to HIs, not t o IP addresses  HIs translated to IP address es in the kernel The Idea IP addr ProcessProcess TransportTransport IP layer Link layer IP address Host Identity Host ID

51. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks 50 IP layer Fragmentation More detailed layering Link Layer ForwardingForwarding IPsec Transport Layer End-to-en d, HITs Hop-by-ho p, IP addres ses HIP MobilityMobility Multi-homingMulti-homing v4/v6 bridge

52. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks 51 Protocol overview Initiator Responder I1: HIT I, HIT R R1: HIT I, [HIT R, puzzle, DH R, HI R ] sig I2: [HIT I, HIT R, solution, DH I, {HI I }] sig R2: [HIT I, HIT R, authenticator] sig User data messages Control Data

53. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks 52 How applications work today (when IPsec is used) IKE Server app socket API IPsec SAD IPsec SAD IPsec SPD IPsec SPD IPsec SPD IPsec SPD IPsec SAD IPsec SAD connect(IP S ) TCP SYN to IP S DNS query ESP protected TCP SYN to IPaddr S TCP SYN from IP C DNS server DNS reply Client app IP DNS library DNS library

54. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks 53 Using HIP with ESP HIP daemon Server app socket API IPsec SAD IPsec SAD IPsec SPD IPsec SPD IPsec SPD IPsec SPD IPsec SAD IPsec SAD TCP SYN to HIT S DNS query ESP protected TCP SYN to IPaddr S convert HITs to IP addresses convert IP addresses to HITs TCP SYN from HIT C DNS server DNS reply Client app HIT DNS library DNS library HIT ----- > {IP addresses} connect(HIT S )

55. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks IPsec Definations  Security policy database (SPD)  Security association database (SAD)  Encapsulating security payload (ESP) 54/55

56. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks 55 HIP as the new waist of TCP/IP v4 app TCPv4 IPv4 Link layer TCPv6 IPv6 v6 appv4 app TCPv4 IPv4 Link layer TCPv6 IPv6 v6 app Host identity

57. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks 56 Introduction to IP based mobility and multi-homing  Mobility implemented at “lP layer”  IP addresses are assigned according to topology  Allows for routing prefix aggregation  Mobile hosts change their topological location  Multi-homed hosts present at many locations  In an IP based m&m solution  Transport & apps do not see address changes or multiple addres ses

58. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks 57  Mobility and multi-homing become duals of each other  Mobile host has many addresses over time  Multi-homed host has many addresses at the same time  Leads to a Virtual Interface Model  A host may have real and virtual interfaces  Merges the “Home Agent” HIP Mobility & Multi-homing

59. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks 58 ESP from MN to CN Mobility protocol Mobile Corresponding UPDATE: HITs, new locator(s), sig UPDATE: HITs, RR challenge, sig ESP on both directions UPDATE: HITs, RR response, sig

60. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Multicast and IP-Mobility  Common issues in both paradigms  Location independent communication/addressing  Location discovery/management  Packet forwarding Location Independent Addressing IP-Multicast –Single ‘logical’ multicast group D -class address –Senders do not know receivers –Receivers do not know senders Mobile-IP –Permanent home address –Temp care-of-address(es) –Address mapping done throu gh the home agent

61. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Location Management  IP-Multicast  Membership location  Done thru IGMP & routing  Meet through the multicast tr ee  Mobile-IP  Mobile node location  Done thru home agent  Meet thru registration of n ew address Packet Forwarding IP-Multicast –Multicast forwarding –Tunnel through the multicast tr ee (e.g., RP) Mobile-IP –Unicast forwarding –Tunnel through home agent

62. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Multicast for Mobility?  Instead of obtaining a new COA and registering with the new f oreign agent (and subsequently with the home agent) and de-r egistering the old address  Use the same logical multicast group address and join/leave th e group as you move Potential Advantages Avoiding ‘triangle routing’ problem Avoiding the need for home/foreign agents to continuously tunnel packets to the MN Smooth hand-off using standard join/prune Using shortest path (source-specific trees)

63. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks (a) All locations visited by the mobile are part of the distribution tree (at some point) (b) When a mobile moves to a certain location, only that location becomes p art of the tree (shown by bold lines) - When the mobile moves to a new location, as in (c) and (d) the distribution tree changes to deliver packets to the new location. Multicast-based Mobility (M&M): Archit ectural Concept

64. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Distribution tree dynamics while roaming CN CN: Correspondent node (sender) Wireless link Mobile Node Multicast-based Mobility (M&M): Archit ectural Concept

65. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Join/Prune dynamics to modify distribution CN CN: Correspondent node (sender) Wireless link Mobile Node

66. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Smooth Hand-off BS1 BS2

67. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks Obtaining MN’s multicast address  A corresponding node (CN) obtains the multicast address of th e MN through:  DNS lookup  similar to getting the unicast (home) address of the MN  requires update of DNS after allocation of multicast addresses to MNs  Startup phase  CN sends packets to home address  Home agent encapsulates packets in multicast pac kets sent to the MN  MN decapsulates these packets and sends a bindin g update to the CN with its multicast address

68. Dr. Amr Talaat Netw 903 Lecture 2 Services & Networks multicast Startup scenario Correspondent Node Mobile Node On first move, the mobile node (MN) sends a binding u pdate to the CN Mobile Node Join Home Agent (HA) Home Network Join Binding Update (MN’s multicast address)