Evaluation of IEEE b and Mobile IPv6 Handoff Times

Transcription

1 Evaluation of IEEE b and Mobile IPv6 Handoff Times Mai Banh 1 Mobile IPv6 Mobile IPv6 (MIPv6) retains connectivity through a single, well-known Home Address of the Mobile Node when it changes its attachments to different subnets Mobile Nodes use a Care-of Address (CoA) to communicate when not at home. MIPv6 handoff: MN changes from one subnetwork to another. Handoff latency: the period that communication between MN and CN is disrupted 2

2 Talk outline MIPv6 handoff steps defined by RFC 3775 Detection movement step Methods for L3 detection Implementation of KAME Experimental setup and results for b and MIPv6 handoff times Evaluation of the results Handoff Impact on application performance 3 MIPv6 Handoff procedures (RFC 3775) MN operations for handoff CN Internet Internet HA AR1 AR2 MN Movement Detection Forming New Care-of Addresses (Stateful or stateless Address autoconfiguration) Sending Binding Updates to the Home Agent (Registration/Deregistration) Wait for HA perform DAD Receiving Binding Acknowledgements Correspondent Registration 4

3 Movement Detection (RFC 3775) Detect L3 handoffs. Generic method that uses the facilities of IPv6 Neighbor Discovery When MN has no packets to send, no frequent Router Advertisements or indications from the linklayer, must depend on other available information (e.g., from lower protocol layers) After detects an L3 handover, MN performs DAD on its link-local address Selects a new default router as a consequence of Router Discovery Performs Prefix Discovery with that new router to form new CoA 5 L3 handoff detection methods (RFC 3775) IPv6 Neighbor Discovery Router Discovery and/or NUD Router Discovery: Information in received Router Advertisements either to detect prefix changes or to discover expired lifetime for RA There might be multiple routers on the same link hearing a new router does not necessary to constitute L3 handoff Multiple routers on the same link might advertise different prefixes. 6

4 Detection methods (continued) For L3 movement confirmation Expired lifetime for RA Advertisement Interval option in RA: indicates the frequency expected to continue to receive future RAs from that router The MN can then implement its own policy to determine how many lost RAs from its current default router and constitute an L3 handover indication. NUD to detect the default router is no longer bi-directionally reachable, in which case the MN must discover a new default router 7 MIPv6 Implementation by KAME MN receives new RAs Form new CoAs and start DAD: IPv6 address auto-configuration mechanism. DAD is performed to ensure MN's link local address not duplicated Movement detection: NUD mechanism. Can performed simultaneously with DAD After L3 detection, select a new CoA Sending Binding Updates to the Home Agent Wait for HA perform DAD Receiving Binding Acknowledgements Correspondent Registration 8

5 IEEE b layer handoff HUB 10Mbps CISO ACCESS POINT 1 SNIFFER BOX CISCO ACCESS POINT 2 MOBILE NODE Both APs on Ch. 10 APs on Ch. 4 and Ch. 10 respectively Mean b hand-off 631ms 667ms Longest hand-off 781ms 825ms Shortest hand-off 506ms 506ms 9 MIPv6 testbed S m artb its H ub S niffer sis0 fxp :D B 8:1:b b b b ::2 H o m e A gent R o uter 2 v r0 2001:D B 8:1:cccc::1 A ccess P o int 1 em :D B 8 :1:a aaa::1 R o uter 1 v r0 2001:D B 8:1 :b b b b ::1 S w itch em :D B 8 :1:b b b b ::3 A ccess R o uter R o uter 3 v r :D B 8:1:d d d d ::1 A ccess P o int 2 w i0 p refix::2 3 0:ab ff:fe1c:b b 1 M o b ile N o d e h if :D B 8 :1:cccc::2 30:a b ff:fe1c:b b 1 (w h en a w a y fro m h o m e) 10

6 MIPv6 handoff times NUD takes 3 seconds MIPv6 hand-off including link layer hand-off CN is MIPv6 node (RA interval: 30ms 70ms) Average hand-off from home to foreign network (in s) Average hand-off from foreign back to home network (in s) CN is non MIPv6 node (RA interval: 30ms 70ms) handoff latency (s) Han d -o ff tim e s ve r s u s RA in te r vals RA in te r vals (m s ) H o m e t o F o re i g n F o re i g n b a c k t o H o m e 11 Handoff impact on application performance On common webcam application Host 1 FreeBSD bridge Host % C u m u lative d is tr ib u tio n o f w e b cam p e r fo r m an ce o ve r 30 h an d o ff s am p le s 80.0% 60.0% % 40.0% 20.0%.0% h an d o ff late n cy (s ) h an d o ff tim e w e b cam in te r r u p te d 12

7 Handoff impact on application performance On TCP bulk data transfer Host 1 FreeBSD bridge Host 2 nttcp BW ( 5 m in s 2 2 s ) nttcp pe r form ance ove r M IPv6 hand-offs ( 6 m in s 9 s ) ( 7 m in s 16 s ) ( 8 m in s 3 9 s ) ( 10 m in s 4 9 s ) ( 14 m in s 3 7 s ) ( 2 2 m in s 2 1s ) ( 3 0 m in s 18 s ) hand-off r ate (hand-offs /m in) 13