CS5984 Mobile Computing

Transcription

1 CS5984 Mobile Computing Dr. Ayman Abdel-Hamid Computer Science Department Virginia Tech Mobile IPv4 Micro-mobility 1

2 Outline solutions 2

3 Local-area Mobility Solutions Within the Mobile IP framework Regional Registration Framework (MIP_RR) Local and Indirect Registration Host-based forwarding schemes Cellular IP (Columbia University) HAWAII (Bell Labs) Multicast-based schemes Assign a scoped multicast address within the foreign domain 3

4 Regional Registration Framework (MIP_RR) 1/3 Home registration Regional registration FA 2 9 GFA FA 3 HA FA 4 FA 5 FA 6 FA 7 Advertises {FA 7, FA 3, FA 1 } {1, 2, 3, and 4}: Home registration when the first enters the foreign domain. {5, 6}: Regional registration with a local handoff from FA 7 to FA 6. {7, 8, 9, and 10}: Home registration involving a local handoff from FA 6 to FA 5. 4

5 Regional Registration Framework (MIP_RR) 2/3 The old FA relays the BU message, received from the new FA, upwards in the hierarchy (to its father FA) specifying itself as the care-of address of the. The father FA performs the following steps delete its s visitor entry, create a binding cache entry for the with care-of address the child FA that sent the BU message, relay the BU message upwards in the hierarchy, and send back a binding acknowledge message to its child FA 5

6 Regional Registration Framework (MIP_RR) 3/3 Tunneling consistency mechanism to clear visitor entries in old path GFA Crossover FA BU FA 2 Reg. Req. FA 3 Reg. Req. BU BU FA 4 FA 5 FA 6 FA 7 Reg. Req. with PFANE Regional registration request Binding update message 6

7 Local and Indirect Registration HA:Home Agent Home Network Foreign Network FA: Foreign Agent FA 4 Local Registration HA Secure tunnel 3 Anchor FA 2 1 Home Network Foreign Network FA 6 Indirect Registration HA 4 Secure tunnel 3 5 Anchor FA 2 1 7

8 Cellular IP 1/2 Cellular IP and Mobile IP Global Internet with Mobile IP Global mobility Wireless access network Wireless access network Mobile IP Cellular IP Local handoffs Local handoffs HA Gateway Router BS BS BS Wireless access network model tunnel FA BS BS 8

9 Cellular IP 2/2 paging update packets Gateway Router A : from B B D : from F E A, D have paging caches FA C G F Paging update packet (routed hop-by-hop towards the GW) paging packet routed to using paging caches Gateway Router A : from B B D : from F E Data packets for FA C G F responds with a routeupdate packet which configures routing caches along the way to the GW 9

10 HAWAII 1/2 Handoff-Aware Wireless Access Internet Infrastructure Uses specialized path setup schemes which install host-based forwarding entries in specific routers to handle intra-domain micro-mobility defaults to using mobile IP for inter-domain macro-mobility requires that obtains a co-located care of address within a domain, nevertheless is required to register with a BS within the domain to be able to better handle handoffs sends path setup update messages during power up and after handoffs HR HA Home Domain R FR Foreign Domain HR: Home Domain Root Router FR: Foreign Domain Root Router domain model within HAWAII HA notified of co-located care of address 10

11 HAWAII 2/2 Router 1 (0): B (3): A Old BS (0): B (2): A Router 0 (0): B A (4): C B C 4 5 A A B C B C 3 2 A B 1 A B 7 Router 2 (0): Default A (5): B 6 New BS (0): Default A (6): B Router 1 (0): B (4): A Old BS (0): B (5): A 5 B A Router 0 C A B B A C 4 3 IP: A C K 6 (0): B (3): C 1 B A A B C 7 Router 2 2 New BS IP: Forwarding path setup scheme ( can listen/transmit to only one BS) Non-Forwarding path setup scheme ( can listen/transmit to multiple BS) 11

12 Multicast and Mobility 1/3 The Deadalus Approach (Berkeley, 1995) maintains the HA concept of Mobile IP pre-assigned a multicast address by HA HA encapsulates any packets destined to and forwards them over the pre-assigned multicast group informs nearby Base Stations about multicast group and controls forwarding/buffering of packets at BSs through a control protocol 12

13 Multicast and Mobility 2/3 A Multicasting-based Mobility Solution (1997) multicast sole mechanism to provide addressing and routing services to s each is assigned a unique multicast IP address (globally unique) approach affects a number of existing protocols such as TCP, ICMP, ARP, IGMP 13

14 Multicast and Mobility 3/3 Fast Handoffs for Wireless Networks (1999) foreign domain arranged as a two level hierarchy with a domain FA at the root and base stations as leafs. assigned a multicast address within the foreign domain by the domain FA (centralized server) domain FA becomes forwarding agent for all s (single point of failure, bottleneck) does not discuss details of multicast address allocation or effects on multicast routing 14

15 Outline A cooperating FA hierarchies local-area mobility support framework 15

16 Cooperating Foreign Agents Hierarchies 1/2 A local-area mobility support framework Efficiently handle local-area movement scenarios within a foreign domain through cooperation between FA hierarchies Provide authentication and replay protection for all protocol messages Not specific to any access technology Explore the hierarchy structure to enhance registration processing 16

17 Cooperating Foreign Agents Hierarchies 2/2 FA hierarchy model Foreign Domain Intra-hierarchy handoffs Hierarchy cooperation Inter-hierarchy handoffs FA Hierarchy 1 FA Hierarchy 2 FA Hierarchy n 17

18 FA Hierarchy Model GFA Foreign Agent Advertisement Regional FAs FA 2 FA 3 {FA6, GFA} FA6@RealmX {FA7, GFA} FA7@RealmX FA 4 FA 5 FA 6 FA 7 Advertise the FA IP address (if not private) for legacy s Hide the hierarchy structure 18

19 Critique of MIP_RR s tunneling consistency Requires smooth handoff mechanism Potential race condition if BU from old path reaches crossover FA before the registration request from new path RFA Crossover FA BU (D old-crossover ) Registration Request (D new-crossover ) Old FA Old path D new-old BU New path New FA Registration Request 19

20 Regional Registrations Framework 1/2 Old FA RFA j In old path New FA RFA i in route to crossover FA Crossover FA (can be GFA) Rreg. Req. Rreg. Req. Rreg. Req. Rreg. Reply Rreg. Reply Rreg. Reply Dereg. (BU) Dereg. (BU) Binding ack. Binding ack. Regional Registration messages (Request/Reply) Route Optimization messages (BU/Binding ack.) Rreg.:Regional Registration Req.:Request Ack.:Acknowledgement Dereg.:Deregistartion 20

21 Replay Protection Regional Registrations Framework 2/2 Crossover FA propagates upwards in the hierarchy towards the GFA a replay protection update message to ensure future successful processing of registrations by upper RFAs in the path This message propagates the new identification value assigned to the by the crossover FA Used for nonce replay protection and timestamp replay protection Type Reserved Home Address New Identification Identification Extensions 21

22 Home Registrations Framework Home Registrations involving local handoffs A home registration is forwarded to the HA to renew the s mobility binding How about the old path? A deregistration mechanism similar to the regional registration framework would clear the old path, but increases packet loss while waiting for the reply from the HA The need to clear the visitor entries on the old path Our solutions KOPA approach (Keep Old Path Alive) SINP approach (Switch Immediately to New Path) 22

23 Intra-Hierarchy Handoffs: The KOPA Approach 1/3 HA Registration Request GFA BU with estimated lifetime, along with new FA IP address information. Old FA can tunnel buffered or future packets to new FA Old FA Old path RFA New path Crossover FA New FA Registration Request Registration Request along with new FA IP address information 23

24 Intra-Hierarchy Handoffs: The KOPA Approach 2/3 What lifetime is used for the BU? BU lifetime = Max {home reg. latency, α * remaining reg. lifetime} Where 0 < α <= 1 (we use α = 0.5) Maintain observed home registration latency at each RFA How the new FA information is propagated without the smooth handoff mechanism? Benefit from the existence of a hierarchy, an old and new path Propagate new FA information along new path to crossover FA, then along old path to old FA through a local care-of address extension 24

25 Intra-Hierarchy Handoffs: The KOPA Approach 3/3 Authentication and replay protection A home registration request would only include home authentication and identification information How can the crossover FA authenticate the request to initiate KOPA? includes a local replay protection extension, such that the crossover FA is capable of ensuring the freshness of its request authenticates its request using a -GFA authentication extension Crossover FA authenticates the request before initiating the tunneling consistency mechanism on the new path 25

26 Intra-Hierarchy Handoffs: The SINP Approach Home Registration Request HA GFA Deregistration mechanism (BU message with zero lifetime) RFA Home Registration Request Crossover FA Old FA Old path New path Home Registration Request New FA Home Registration Request Regional Registration Reply The crossover FA switches the tunneling path to the new path before receiving a home registration reply. View such registrations as a truly combined home and regional registrations The local handoff completion does not have to wait for a reply from the HA 26

27 Performance Evaluation 1/4 CH 1.5 Mbps 20 ms HA 1.5 Mbps LD GFA-HA FA 2,1 GFA 100 Mbps LD FA-FA FA 2,2 Foreign domain FA 3,1 FA 3,2 FA 3,3 FA 3,4 FA 4,1.. FA 4,4 FA 4,5 FA 4,8 LD: Link delay Simulated Network Topology 27

28 Performance Evaluation 2/4 UDP Traffic KOPA SINP Base MIP DOP Average lost packets per handoff Average encapsulated packets per HR-LH GFA to HA delay (in msec) GFA to HA delay (in msec) Using the KOPA approach 28

29 Performance Evaluation 3/4 UDP Traffic Average lost packets per HR-LH KOPA SINP DOP GFA to HA delay (in msec) Average dropped packets per handoff KOPA SINP Playout delay in msec 29

30 Performance Evaluation 4/4 TCP Traffic KOPA SINP Base MIP DOP KOPA SINP Base MIP DOP TCP Throughput (M bps) GFA to HA delay (in msec) Retransmission Ratio GFA to HA delay (in msec) 30

31 Inter-Hierarchy Handoffs 1/8 One FA hierarchy in foreign domain is a burden on the GFA. (single point of failure, maintain routing entries for all s) If multiple FA hierarchies are deployed, no configurable scalable cooperation is envisioned between hierarchies Reduce the number of required security associations between FAs in different hierarchies Shield the HA from the s movement within the foreign domain 31

32 Inter-Hierarchy Handoffs 2/8 Routing Zone 1 GFA 1 GFA 1 Hierarchy Foreign Domain Configurable Cooperation GFA 2 GFA 2 Hierarchy Routing Zone 2 Routing Zone i GFA i GFA i Hierarchy Partition foreign domain into routing zones Each routing zone is an independent FA hierarchy FAs advertise their own IP address and the GFA address registers GFA 1 as its care-of address. GFA 1 is termed the s HRGFA (Home-registered GFA). 32

33 Inter-Hierarchy Handoffs 3/8 Configurable Cooperation Cooperation is only allowed between the roots of the FA hierarchies (2 security associations between each pair of GFAs) The FAs advertise two new options in their mobility agent advertisements will this GFA accept cooperation requests from other GFAs? will this GFA send cooperation requests on behalf of the? 33

34 Inter-Hierarchy Handoffs 4/8 Routing Zone 1 GFA 1 Old tunnel Foreign Domain New tunnel Routing Zone i GFA i GFA 1 Hierarchy GFA 2 Routing Zone 2 GFA i Hierarchy GFA 2 Hierarchy The movement between FA hierarchies 34

35 Inter-Hierarchy Handoffs 5/8 Home registration lifetime expiration Enter foreign domain Home reg. Ads from the current or HRGFA hierarchy Event transition Automatic transition Regional reg. Homeregional AD_HFA or reg. HRE_HANDOFF_HFA reg.: registration Ads: FA advertisements AD_HFA: Ads from another FA hierarchy HRE_HANDOFF_HFA: Home registration lifetime expiration while moving to another hierarchy Registration State Diagram 35

36 Inter-Hierarchy Handoffs 6/8 Home-regional Registration A home registration with a regional data extension The current GFA attempts to contact the HRGFA using the information in the regional extension If success, the current GFA receives tunneled packets for the from the HRGFA If the HRGFA does not respond, use the s home credentials to perform a home registration on behalf of the 36

37 Inter-Hierarchy Handoffs 7/8 Regional FA in GFA j hierarchy GFA j GFA i ('s HRGFA) Home-regional registration request Registration reply Home-regional registration request Registration reply Home-regional registration request Registration reply If the RZFA accepted the regional registration request, the ZFA j hierarchy is now able to authenticate any future registration requests by the. The home-regional registration process, in case the RZFA is reachable. 37

38 Inter-Hierarchy Handoffs 8/8 Home-regional registration request Home registration reply Regional FA in GFA j hierarchy Home-regional registration request GFA j Home registration reply Home-regional registration request ICMP errors GFA i (The 's HRGFA) Home registration reply HA Home registration request Upon successful registration, the 's HRGFA is changed within the foreign domain. The home-regional registration process, in case the HRGFA is not reachable. 38

39 Performance Evaluation 1/3 CH 1.5 Mbps 20 ms HA LD: Link Delay 1.5 Mbps GFA 1 LD HA-GFA (Default is 20 ms) 10 Mbps LD GFA-GFA (Default is 1 ms) 1.5 Mbps GFA 2 Local-area Network 10 Mbps 1 ms GFA i GFA 1 Hierarchy GFA 2 Hierarchy FA 2,1 FA 2,2 FA. 3,1 FA 3,4 Foreign domain Simulated Network Topology FA 4,1 FA 4,2 FA 4,7 FA 4,8. 39

40 Performance Evaluation 2/3 UDP Traffic NC-GFAs/A NC-GFAs/V C-GFAs/A C-GFAs/V C-GFAs NC-GFAs Avergae lost packets per handoff HA-GFA link delay (msec) Avergae lost packets per handoff GFA-HRGFA link delay (msec) 40

41 Performance Evaluation 3/3 TCP Traffic NC-GFAs C-GFAs NC-GFAs C-GFAs TCP Throughput (Mbps) GFA-HA link delay (msec) Retransmission Ratio GFA-HA link delay (msec) 41