Presentation on theme: "Group #1: Protocols for Wireless Mobile Environments."— Presentation transcript:
Group #1: Protocols for Wireless Mobile Environments
2 Main Message Changing the view on mobility: –Mobility has become an integral attribute of the Internet and we need to design for it. –Without mobility support, the Internet cannot be invisible. There is a big gap between the opportunities that mobility enables and the practical protocols that can take advantage of it. Design for mobility requires a clean-slate approach to communication protocols in wireless networks and the Internet Design for mobility has direct implications on the Internet design, with in-network storage and localization information being key factors Standards are needed for benchmarks.
3 Why Is Mobility Important? (1) Mobility impacts the conditions in which protocols must operate, the state and context that nodes can use to communicate, and the problems that protocols must solve. Examples: –The state of links are functions of mobility (e.g., link lifetime, fading, multipath effects, direction of a link, etc.) –The neighborhood of a node changes with mobility, which impacts reliable exchanges, channel division (space, time, code, frequency) among neighbors, and forms of cooperation between senders and receivers (e.g., virtual MIMO, network coding) –End-to-end paths change with mobility, which impacts path characteristics (in-order delivery, delay, throughput, lifetime of paths, etc.) and the allocation of resources over paths to satisfy application requirements.
4 Why Is Mobility Important? (2) Examples: –Supporting security is more difficult with mobility: Identities of trusted nodes must change –Privacy can be compromised with mobility: Example: Node can be tracked by the perceived location of its transmissions –Layering of protocols is hard(er) with mobility –Policy-based dissemination of information is more difficult with mobility (dynamic routing with multiple constraints) –Feedback to control data rate is not as useful if paths change (bottleneck state is stale) –Some forms of dissemination is enabled or simplified with mobility.
5 Changing the View on Mobility Mobility is an attribute and we need to design for mobility. Some Ideas: Some protocols benefit from mobility: group mobility, etc. Use mobility as a mechanism for information dissemination Controlled mobility: nodes move around to improve topology, nodes move around to deliver data, store-carry- forward, trajectory planning and changing what routes Energy conservation as a metric Interest-driven dissemination: How should opportunistic data mules handle data? Disseminate through PHY movement of nodes Use wired network Content-driven routing
6 Designing for Mobility: A Clean Slate Exploit broadcast nature of links & in-network storage OSI/TCP architecture is no longer “the best”…What is the new slate? –MAC issues: MAC should work on broadcast and directional transmissions; support many-to-many rather than one-to-one communication –Network issues: Naming (no need for addresses?), attribute- based queries, geo-location is important, resource discovery (no DNS) –“Beyond routing”: resource discovery replaces route discovery; need for binding of resources/services on the basis of names; need for route binding
7 Designing for Mobility: A Clean Slate (cont) –Route binding: “Opportunistic use of resources” cooperative xmit schemes (take advantage of gains at PHY) incentive mechanisms (battery life, use of spectrum), cooperation using memory, virtual MIMO, Use mobility of nodes to cooperate as data mules; need for coordination to decide which nodes move where Peer-to-peer opportunistic transmissions: how to cache, how to route, post box (beyond foreign agent). Trade storage for retransmissions –Transmission control: Change S to D ARQ to opportunistic S-proxies-D ARQ –State information vs opportunism: Use of CSI induced by mobility to help cooperation vs opportunistically forwarding w/o CSI. –Tolerance to various forms of disruption (e.g., no connections)
8 Changing The Internet Design Use of storage and location information must be considered in the global routing design. Use of location information: IPv6 can be used but we must find anonymous location information in addressing…use of proxies and in-net storage. Easier approaches are above IP. Privacy and security implications There are localized protocols that can (should be) used (e.g., a DHCP-like approach) Mobility creates a stronger focus on security: –We do not know the local neighborhood. Opportunistic mobile routing infrastructures will become important Mobility changes the expectations for services (anywhere, anytime), but maintaining performance with seamless mobility is difficult.
9 Role of Standards What should be standardized? –Benchmarking different protocols (modeling and otherwise) –Understand dynamics of system to understand what to standardize –Need for a reference model capturing connectivity structures and spanning different scenarios and protocols. –Parameters that should be of interest are open –Look at the “connectivity structure” of a network (dense or sparse, guidelines)
10 Multicast Coupled with mobility, maintaining routing structure is hard Using mcast to satisfy localized services Potentially more overhead that unicast In-network storage can help, but the consistency of data is an issue Need to study one-to-many-to-one (convergecast + multicast + anycast) Pull vs push with in-network storage
11 Things to Things Communication Location is key aspect of interaction Applications Mobile sensors (e.g., health monitoring) with limited power need protocols Internet at the service of users and things that move.