Mobile Group Communication Mobility & Multicast Status The Multicast Mobility Problem Listener Mobility ASM Source Mobility SSM Source Mobility Conclusions & Outlook 1 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
Where are we going Mobile today? 2 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
We need Multicast Services for Public Content Broadcasting Voice and Video Conferencing Collaborative Environments Gaming Self Organisation of Distributed Systems All of this MOBILE! 3 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
Status: Where are we today? o Internet Mobility - Mobile IPv6 - RFC 3775 (June 2004, implemented) o Real-Time Mobility - FMIPv6, HMIPv6 RFCs 4068, 4140 (August 2005, first implementations) o Multicast Mobility - Rough ideas in IETF - Some proposals in IRTF - First problem statement in Vancouver, Nov. 2005 o NGNs: DVB IP distribution services 4 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
Multicast: What is the Problem? othere is Any Source Multicast: - Listeners harvest streams from any source - Sparse & dense mode routing - Complex to deploy, Interdomain problem othere is Source Specific Multicast: - Listeners subscribe to known sources - Immediate shortest path trees - Easy to deploy, domain transparent 5 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
Multicast Receiver Mobility o Multicast Routing is Mobile : - On handover listeners may re-subscribe to multicast group (ASM & SSM) - Routing will construct delivery branch o Problem: Multicast routing not seamless, but slow - Branch construction up to 30 s - Real-time communication requirements: handover below 100 ms! 6 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
Multicast Mobility Approaches o Remote Subscription - Show all movement by local multicast subscription o Bi-directional Tunneling - Hide all movement by tunneling via Home Agent o Agent Based - Compromise: Intermediate agents shield Mobile - Approaches: Extend unicast acceleration schemes M-FMIPv6, M-HMIPv6, 7 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
Fast Multicast Protocol for MIPv6 draft-suh-mipshop-fmcast-mip6-00 Remote subscription with agent support Mobile multicast reception only Built on Fast Handovers for MIPv6 (FMIPv6) Predictive handovers based on L2 : L3 map Handled at access routers Extends signalling of FMIPv6 by multicast address option 8 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
M-FMIPv6: Prediction 9 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
M-FMIPv6: Forwarding 10 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
M-FMIPv6: Handover 11 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
M-FMIPv6: Completion 12 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
Seamless Multicast Handover in a HMIPv6 Environment draft-schmidt-waehlisch-mhmipv6-04 Agent based: MAP as Multicast agent Mobile multicast reception and source Built on Hierarchical MIPv6 (HMIPv6) For mobile listeners: Micro mobile handovers hidden by MAP Reactive handovers between MAPs Unicast (tunnel) forwarding MN : MAP Change to remote subscription with MAP attendance Extends signalling of HMIPv6 by multicast advertisement flag 13 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
M-HMIPv6: Multicast Listener 14 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
M-HMIPv6: MAP-Local Handover 15 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
M-HMIPv6: Inter-MAP Handover 16 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
M-HMIPv6: Completion 17 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
Multicast Source Mobility Problem o Distribution tree (somehow) rooted at source: - Collapses after movement - Reconstruction very slow (up to minutes) o Address Duality Problem: - Source address is logical & topological ID o Source Activation Problem: - New source to be discovered by interdomains o Decoupling Problem: - Source has no feedback from receivers 18 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
Multicast Source Mobility Approaches o Remote Subscription - Show all movement by local multicast subscription o Bi-directional Tunneling - Hide all movement by tunneling via Home Agent o Agent Based - Use current Care-of-Address for Routing - Use Home-Addres in Destination Option at Receiver - Tree Walking 19 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
M-HMIPv6: Mobile Multicast Source Mobile multicast sender anchored at MAP: Use Home Address Destination Option (CN must not verify BC on mcast) On handover: Initially tunnel through old MAP Initiate new tree by pure IP packets Handover on (protocol dependent) timeout On rapid Movement: stay with established MAP 20 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
M-HMIPv6: Multicast Source 21 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
M-HMIPv6: MAP-Local Handover 22 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
M-HMIPv6: Inter-MAP Handover (1) 23 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
M-HMIPv6: Inter-MAP Handover (2) 24 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
Multicast Source Mobility: SSM Problems o Receivers need to Subscribe to Source Address: -HoA& current CoA needed at Receiver o Routers Maintain Source Specific States: -HoA& current CoA needed at Routers o Decoupling: Source cannot Control Receiver Updates: - May loose receivers on handover 25 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
Multicast Source Mobility Approaches o Remote Subscription - Show all movement by local multicast subscription o Bi-directional Tunneling - Hide all movement by tunneling via Home Agent o Agent Based - Use current Care-of-Address for Routing - Use Home-Addres in Destination Option at Receiver - Tree Walking 26 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
Bi-Directional Tunneling 27 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt How good is BT?
Simulation: BT in ATT Network 28 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
Internet with 154 Core Nodes 29 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
Internet with 1.540 Core Nodes 30 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
Internet with 15.400 Core Nodes 31 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
What to do with Mobile SSM? Need to Change Routing: Logical (HoA) and topological (CoA) identifier needed at client and routing layer Need to keep contact to clients after handover : Some mobility persistent entities? Current Ideas: Re-introduce shared trees Re-use trees What effect does mobility impose on SPTs? 32 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
Analysis of Moving Distribution Trees Multicast Distribution Trees subsequent under Mobility are highly correlated Previous and Next Tree overlap from receivers downward Coinciding subtrees: self-similar URT Results in frequent re-use of Mcast Routers Two characteristic measures Step-Size : pdr-to-ndr Distance Tree evolvement: Number of Receivers 33 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
Simulation Study: Tree Coincidence wrt. Step-Size 80 % Coincidence for 40 Receivers and a mobility step-size of 5 34 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
Simulation Study: Tree Coincidence wrt. Tree Evolvement > 80 % Coincidence for a mobility step-size of 5 and 100 Receivers 35 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
Shared Tree Mobility Use Rendezvous Point as Mobility Anchor: Mobility-aware Rendezvous Point (MRP) Need to Change Routing: Extend (*,G) states to (HoA, G, MRP-ID) Modify RPF-Check to identify CoA* sources with HoA Operate interdomain handovers via MRP-ID Source Romdhani et al: Transparent Handover for Mobile Multicast Sources, In: Proceedings of the IEEE ICN'06, IEEE Press, April 2006 36 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
Mobility-aware Rendezvous Points 37 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
Source Specific Tree Modification Need to Change Routing: Extend (CoA,G) states to (CoA,HoA,G) Need to Preserve Previous Trees: Keep contact subsequent to handover Idea: Morph Previous into Next Tree: Elongate root (modify RPF Check) Discover shortcuts Dismiss unneeded branches Source - Schmidt & Wählisch: Extending SSM to MIPv6 -- Problems Solutions and Improvements, Computational Methods in Science and Technology, Vol. 11, No. 2, 38 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt pp. 147--152, Poznan:Scientific Publ. OWN --- Polish Academy of Sciences, Nov. 2005.
Tree Morphing 39 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
Root Elongation Phase 40 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
First Shortcut 41 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
Optimized Tree 42 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
Performance Snapshot 43 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
Conclusions & Outlook Mobile Multicast is Emerging Issue Intricate Problem: - Mobile Receivers on Good Way - Mobile ASM Sources Difficult - Mobile SSM Sources Hard New Approach: Tree Morphing - Seamless & free of encapsulation - But requires change of SSM routing protocols Future Development: Analysis & Simulations & Optimizations Detail out + Security Layer 44 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt
Other Approaches Dynamically optimising agents Overlay Multicast XCast References Romdhani, I., Kellil, M., Lach, H.-Y. et. al. "IP Mobile Multicast: Challenges and Solutions", IEEE Comm. Surveys, 6, 1, 2004. Schmidt, Wählisch: Multicast Mobility in MIPv6: Problem Statement, draft-irtf-mobopts-mmcastv6-ps-01.txt, 2006. Schmidt, Wählisch: Morphing Distribution Trees - On the Evolution of Multicast States under Mobility and an Adaptive Routing Scheme for Mobile SSM Sources, Telecommunication Systems, Berlin Heidelberg:Springer, October 2006. (in press) www.rfc-editor.org 45 Prof. Dr. Thomas Schmidt http:/www.informatik.haw-hamburg.de/~schmidt