C08 Network Protocols

Motivation for Mobile IPRoutingbased on IP destination address, network prefix (e.g. 129.13.42) determines physical subnetchange of physical subnet implies change of IP address to have a topological correct address (standard IP) or needs special entries in the routing tablesSpecific routes to end-systems?change of all routing table entries to forward packets to the right destinationdoes not scale with the number of mobile hosts and frequent changes in the location, security problemsChanging the IP-address?adjust the host IP address depending on the current locationalmost impossible to find a mobile system, DNS updates take to long timeTCP connections break, security problems

Prof. Dr.-Ing. Jochen H. Schillerwww.jochenschiller.deMC - 2008

Requirements for Mobile IPv4 (RFC 3344, was: 3220, was: 2002 , updated by: 4721)Transparencymobile end-systems keep their IP addresscontinuation of communication after interruption of link possiblepoint of connection to the fixed network can be changedCompatibilitysupport of the same layer 2 protocols as IPno changes to current end-systems and routers requiredmobile end-systems can communicate with fixed systemsSecurityauthentication of all registration messagesEfficiency and scalabilityonly little additional messages to the mobile system required (connection typically via a low bandwidth radio link)world-wide support of a large number of mobile systems in the whole Internet


TerminologyMobile Node (MN)system (node) that can change the point of connection to the network without changing its IP addressHome Agent (HA)system in the home network of the MN, typically a routerregisters the location of the MN, tunnels IP datagrams to the COAForeign Agent (FA)system in the current foreign network of the MN, typically a routerforwards the tunneled datagrams to the MN, typically also the default router for the MNCare-of Address (COA)address of the current tunnel end-point for the MN (at FA or MN)actual location of the MN from an IP point of viewcan be chosen, e.g., via DHCPCorrespondent Node (CN)communication partner


Example networkmobile end-systemInternetrouterrouterrouterend-systemFAHAMNhome networkforeign network(physical home networkfor the MN)(current physical network for the MN)CN


Data transfer to the mobile systemInternetsenderFAHAMNhome networkforeignnetworkreceiver1231. Sender sends to the IP address of MN, HA intercepts packet (proxy ARP)2. HA tunnels packet to COA, here FA, by encapsulation3. FA forwards the packet to the MNCN


Data transfer from the mobile systemInternetreceiverFAHAMNhome networkforeign networksender11. Sender sends to the IP address of the receiver as usual, FA works as default routerCN


OverviewCNrouterHArouterFAInternetrouter1.2.3.homenetworkMNforeignnetwork4.CNrouterHArouterFAInternetrouterhomenetworkMNforeignnetworkCOA


Network integrationAgent AdvertisementHA and FA periodically send advertisement messages into their physical subnetsMN listens to these messages and detects, if it is in the home or a foreign network (standard case for home network)MN reads a COA from the FA advertisement messagesRegistration (always limited lifetime!)MN signals COA to the HA via the FA, HA acknowledges via FA to MNthese actions have to be secured by authentication AdvertisementHA advertises the IP address of the MN (as for fixed systems), i.e. standard routing informationrouters adjust their entries, these are stable for a longer time (HA responsible for a MN over a longer period of time)packets to the MN are sent to the HA, independent of changes in COA/FA


type = 16length = 6 + 4 * #COAsR: registration requiredB: busy, no more registrationsH: home agentF: foreign agentM: minimal encapsulationG: GRE encapsulationr: =0, ignored (former Van Jacobson compression)T: FA supports reverse tunnelingreserved: =0, ignoredAgent advertisementpreference level 1router address 1#addressestypeaddr. sizelifetimechecksumCOA 1COA 2type = 16sequence numberlength0781516312423codepreference level 2router address 2. . . registration lifetime. . . RBHFMGr reservedT


RegistrationtMNHAregistrationrequestregistrationreplytMNFAHAregistrationrequestregistrationrequestregistrationreplyregistrationreply


Mobile IP registration requesthome agenthome addresstype = 1lifetime0781516312423T xidentificationCOAextensions . . . S: simultaneous bindingsB: broadcast datagramsD: decapsulation by MNM mininal encapsulationG: GRE encapsulationr: =0, ignoredT: reverse tunneling requestedx: =0, ignored


Mobile IP registration replyhome agenthome addresstype = 3lifetime078151631codeidentificationextensions . . . Example codes:registration successful0 registration accepted1 registration accepted, but simultaneous mobility bindings unsupportedregistration denied by FA65 administratively prohibited66 insufficient resources67 mobile node failed authentication68 home agent failed authentication69 requested Lifetime too longregistration denied by HA129 administratively prohibited131 mobile node failed authentication133 registration Identification mismatch135 too many simultaneous mobility bindings


Encapsulationoriginal IP headeroriginal datanew datanew IP headerouter headerinner headeroriginal data


Encapsulation IEncapsulation of one packet into another as payloade.g. IPv6 in IPv4 (6Bone), Multicast in Unicast (Mbone)here: e.g. IP-in-IP-encapsulation, minimal encapsulation or GRE (Generic Record Encapsulation)IP-in-IP-encapsulation (mandatory, RFC 2003)tunnel between HA and COACare-of address COAIP address of HATTLIP identificationIP-in-IPIP checksumflagsfragment offsetlengthDS (TOS)ver.IHLIP address of MNIP address of CNTTLIP identificationlay. 4 prot.IP checksumflagsfragment offsetlengthDS (TOS)ver.IHLTCP/UDP/ ... payload


Encapsulation IIMinimal encapsulation (optional)avoids repetition of identical fieldse.g. TTL, IHL, version, DS (RFC 2474, old: TOS)only applicable for non fragmented packets, no space left for fragment identificationcare-of address COAIP address of HATTLIP identificationmin. encap.IP checksumflagsfragment offsetlengthDS (TOS)ver.IHLIP address of MNoriginal sender IP address (if S=1)Slay. 4 protoc.IP checksumTCP/UDP/ ... payloadreserved


Generic Routing EncapsulationCare-of address COAIP address of HATTLIP identificationGREIP checksumflagsfragment offsetlengthDS (TOS)ver.IHLIP address of MNIP address of CNTTLIP identificationlay. 4 prot.IP checksumflagsfragment offsetlengthDS (TOS)ver.IHLTCP/UDP/ ... payloadrouting (optional)sequence number (optional)key (optional)offset (optional)checksum (optional)protocolrec.rsv.ver.CRKSsRFC 1701RFC 2784 (updated by 2890)reserved1 (=0)checksum (optional)protocolreserved0ver.C


Optimization of packet forwardingProblem: Triangular Routingsender sends all packets via HA to MNhigher latency and network loadSolutionssender learns the current location of MNdirect tunneling to this locationHA informs a sender about the location of MNbig security problems!Change of FApackets on-the-fly during the change can be lostnew FA informs old FA to avoid packet loss, old FA now forwards remaining packets to new FAthis information also enables the old FA to release resources for the MN


Change of foreign agent CNHAFAoldFAnewMNMN changes locationtDataDataDataUpdateACKDataDataRegistrationUpdateACKDataDataDataWarningRequestUpdateACKDataData


Reverse tunneling (RFC 3024, was: 2344)InternetreceiverFAHAMNhome networkforeign networksender3211. MN sends to FA2. FA tunnels packets to HA by encapsulation3. HA forwards the packet to the receiver (standard case)CN


Mobile IP with reverse tunnelingRouter accept often only topological correct addresses (firewall!)a packet from the MN encapsulated by the FA is now topological correctfurthermore multicast and TTL problems solved (TTL in the home network correct, but MN is to far away from the receiver)Reverse tunneling does not solveproblems with firewalls, the reverse tunnel can be abused to circumvent security mechanisms (tunnel hijacking)optimization of data paths, i.e. packets will be forwarded through the tunnel via the HA to a sender (double triangular routing)The standard is backwards compatiblethe extensions can be implemented easily and cooperate with current implementations without these extensions Agent Advertisements can carry requests for reverse tunneling


Mobile IP and IPv6 (RFC 3775)Mobile IP was developed for IPv4, but IPv6 simplifies the protocolssecurity is integrated and not an add-on, authentication of registration is includedCOA can be assigned via auto-configuration (DHCPv6 is one candidate), every node has address auto-configurationno need for a separate FA, all routers perform router advertisement which can be used instead of the special agent advertisement; addresses are always co-locatedMN can signal a sender directly the COA, sending via HA not needed in this case (automatic path optimization)soft hand-over, i.e. without packet loss, between two subnets is supportedMN sends the new COA to its old routerthe old router encapsulates all incoming packets for the MN and forwards them to the new COAauthentication is always granted


Problems with mobile IPSecurityauthentication with FA problematic, for the FA typically belongs to another organization no protocol for key management and key distribution has been standardized in the Internetpatent and export restrictionsFirewallstypically mobile IP cannot be used together with firewalls, special set-ups are needed (such as reverse tunneling)QoSmany new reservations in case of RSVPtunneling makes it hard to give a flow of packets a special treatment needed for the QoSSecurity, firewalls, QoS etc. are topics of research and discussions


Security in Mobile IPSecurity requirements (Security Architecture for the Internet Protocol, RFC 4301, was: 1825, 2401)Integrity any changes to data between sender and receiver can be detected by the receiverAuthentication sender address is really the address of the sender and all data received is really data sent by this senderConfidentiality only sender and receiver can read the dataNon-Repudiation sender cannot deny sending of dataTraffic Analysis creation of traffic and user profiles should not be possibleReplay Protection receivers can detect replay of messages


IP security architecture ITwo or more partners have to negotiate security mechanisms to setup a security associationtypically, all partners choose the same parameters and mechanismsTwo headers have been defined for securing IP packets:Authentication-Headerguarantees integrity and authenticity of IP packetsif asymmetric encryption schemes are used, non-repudiation can also be guaranteed

Encapsulation Security Payloadprotects confidentiality between communication partnersESP headerIP headerencrypted data


Mobile Security Association for registrations parameters for the mobile host (MH), home agent (HA), and foreign agent (FA)Extensions of the IP security architectureextended authentication of registration

prevention of replays of registrationstime stamps: 32 bit time stamps + 32 bit random numbernonces: 32 bit random number (MH) + 32 bit random number (HA)

registration replyregistration requestregistration requestIP security architecture IIMHFAHAregistration replyMH-HA authenticationMH-FA authenticationFA-HA authentication


Key distributionHome agent distributes session keys

foreign agent has a security association with the home agentmobile host registers a new binding at the home agenthome agent answers with a new session key for foreign agent and mobile nodeFAMHHAresponse:EHA-FA {session key}EHA-MH {session key}


IP Micro-mobility supportMicro-mobility support:Efficient local handover inside a foreign domain without involving a home agentReduces control traffic on backboneEspecially needed in case of route optimization

Example approaches (research, not products):Cellular IPHAWAIIHierarchical Mobile IP (HMIP)

Important criteria: Security Efficiency, Scalability, Transparency, Manageability


Cellular IPOperation:CIP Nodes maintain routing entries (soft state) for MNsMultiple entries possibleRouting entries updated based on packets sent by MNCIP Gateway:Mobile IP tunnel endpointInitial registration processingSecurity provisions:all CIP Nodes share network keyMN key: MD5(net key, IP addr)MN gets key upon registration


Cellular IP: SecurityAdvantages:Initial registration involves authentication of MNs and is processed centrally by CIP GatewayAll control messages by MNs are authenticatedReplay-protection (using timestamps)

Potential problems:MNs can directly influence routing entriesNetwork key known to many entities (increases risk of compromise)No re-keying mechanisms for network keyNo choice of algorithm (always MD5, prefix+suffix mode)Proprietary mechanisms (not, e.g., IPSec AH)


Cellular IP: Other issuesAdvantages:Simple and elegant architectureMostly self-configuring (little management needed)Integration with firewalls / private address support possible

Potential problems:Not transparent to MNs (additional control messages)Public-key encryption of MN keys may be a problem for resource-constrained MNsMultiple-path forwarding may cause inefficient use of available bandwidth


HAWAIIOperation:MN obtains co-located COA and registers with HAHandover: MN keeps COA, new BS answers Reg. Request and updates routersMN views BS as foreign agent

Security provisions:MN-FA authentication mandatoryChallenge/Response Extensions mandatory BS12334


HAWAII: SecurityAdvantages:Mutual authentication and C/R extensions mandatoryOnly infrastructure components can influence routing entries

Potential problems:Co-located COA raises DHCP security issues (DHCP has no strong authentication)Decentralized security-critical functionality (Mobile IP registration processing during handover) in base stationsAuthentication of HAWAII protocol messages unspecified (potential attackers: stationary nodes in foreign network)MN authentication requires PKI or AAA infrastructure


HAWAII: Other issuesAdvantages:Mostly transparent to MNs (MN sends/receives standard Mobile IP messages)Explicit support for dynamically assigned home addresses

Potential problems:Mixture of co-located COA and FA concepts may not be supported by some MN implementationsNo private address support possible because of co-located COA


Hierarchical Mobile IPv6 (RFC 4140)Operation:Network contains mobility anchor point (MAP)mapping of regional COA (RCOA) to link COA (LCOA)Upon handover, MN informs MAP onlygets new LCOA, keeps RCOAHA is only contacted if MAP changes

Security provisions:no HMIP-specific security provisionsbinding updates should be authenticatedMAPARMNARMNHAbindingupdateRCOALCOAoldLCOAnew


Hierarchical Mobile IP: SecurityAdvantages:Local COAs can be hidden, which provides at least some location privacyDirect routing between CNs sharing the same link is possible (but might be dangerous)

Potential problems:Decentralized security-critical functionality (handover processing) in mobility anchor pointsMNs can (must!) directly influence routing entries via binding updates (authentication necessary)


Hierarchical Mobile IP: Other issuesAdvantages:Handover requires minimum number of overall changes to routing tablesIntegration with firewalls / private address support possible

Potential problems:Not transparent to MNsHandover efficiency in wireless mobile scenarios:Complex MN operationsAll routing reconfiguration messages sent over wireless link


DHCP: Dynamic Host Configuration ProtocolApplicationsimplification of installation and maintenance of networked computerssupplies systems with all necessary information, such as IP address, DNS server address, domain name, subnet mask, default router etc.enables automatic integration of systems into an Intranet or the Internet, can be used to acquire a COA for Mobile IPClient/Server-Modelthe client sends via a MAC broadcast a request to the DHCP server (might be via a DHCP relay)clientrelayclientserverDHCPDISCOVERDHCPDISCOVER


DHCP - protocol mechanismstimeserver(not selected)clientserver(selected)initializationcollection of repliesselection of configurationinitialization completedreleaseconfirmation ofconfigurationdelete contextdetermine theconfigurationDHCPDISCOVERDHCPOFFERDHCPREQUEST (reject)DHCPACKDHCPRELEASEDHCPDISCOVERDHCPOFFERDHCPREQUEST (options)determine theconfiguration


DHCP characteristicsServerseveral servers can be configured for DHCP, coordination not yet standardized (i.e., manual configuration)Renewal of configurationsIP addresses have to be requested periodically, simplified protocolOptionsavailable for routers, subnet mask, NTP (network time protocol) timeserver, SLP (service location protocol) directory, DNS (domain name system)


Mobile ad hoc networksStandard Mobile IP needs an infrastructureHome Agent/Foreign Agent in the fixed networkDNS, routing etc. are not designed for mobilitySometimes there is no infrastructure!remote areas, ad-hoc meetings, disaster areascost can also be an argument against an infrastructure!Main topic: routingno default router availableevery node should be able to forwardABC


Solution: Wireless ad-hoc networksNetwork without infrastructureUse components of participants for networking

ExamplesSingle-hop: All partners max. one hop apartBluetooth piconet, PDAs in a room, gaming devices

Multi-hop: Cover larger distances, circumvent obstaclesBluetooth scatternet, TETRA police network, car-to-car networks

Internet: MANET (Mobile Ad-hoc Networking) group


Manet: Mobile Ad-hoc Networking


Problem No. 1: RoutingHighly dynamic network topologyDevice mobility plus varying channel qualitySeparation and merging of networks possibleAsymmetric connections possiblegood linkweak linktime = t1time = t2N1N4N2N5N3N1N4N2N5N3N6N7N6N7


Traditional routing algorithmsDistance Vectorperiodic exchange of messages with all physical neighbors that contain information about who can be reached at what distanceselection of the shortest path if several paths availableLink Stateperiodic notification of all routers about the current state of all physical links router get a complete picture of the networkExampleARPA packet radio network (1973), DV-Routingevery 7.5s exchange of routing tables including link qualityupdating of tables also by reception of packetsrouting problems solved with limited flooding


Routing in ad-hoc networksTHE big topic in many research projectsFar more than 50 different proposals existThe most simplest one: Flooding!

ReasonsClassical approaches from fixed networks failVery slow convergence, large overheadHigh dynamicity, low bandwidth, low computing power

Metrics for routingMinimalNumber of nodes, loss rate, delay, congestion, interference MaximalStability of the logical network, battery run-time, time of connectivity


Problems of traditional routing algorithmsDynamic of the topologyfrequent changes of connections, connection quality, participants

Limited performance of mobile systemsperiodic updates of routing tables need energy without contributing to the transmission of user data, sleep modes difficult to realizelimited bandwidth of the system is reduced even more due to the exchange of routing informationlinks can be asymmetric, i.e., they can have a direction dependent transmission quality


DSDV (Destination Sequenced Distance Vector, historical)Early workon demand version: AODV

Expansion of distance vector routing

Sequence numbers for all routing updatesassures in-order execution of all updatesavoids loops and inconsistencies

Decrease of update frequencystore time between first and best announcement of a path inhibit update if it seems to be unstable (based on the stored time values)


Dynamic source routing (DSR)Reactive routing protocol2 phases, operating both on demand:Route discoveryUsed only when source S attempts to to send a packet to destination DBased on flooding of Route Requests (RREQ)Route maintenancemakes S able to detect, while using a source route to D, if it can no longer use its route (because a link along that route no longer works)


DSR: Route discovery (1)EGMHRFABCIDSKNLPJQ


DSR: Route discovery (2)EGMHRFABCIDSKNLPJQ(S)


DSR: Route discovery (3)EGMHRFABCIDSKNLPJQ(S,A)(S,E)


DSR: Route discovery (4)EGMHRFABCIDSKNLPJQ(S,E,G)(S,B,C)


DSR: Route discovery (5)EGMHRFABCIDSKNLPJQ(S,E,G,J)(S,A,F,H)


DSR: Route discovery (6)EGMHRFABCIDSKNLPJQ(S,A,F,H,K)


DSR: Route discovery (7)EGMHRFABCIDSKNLPJQ(S,A,F,H,K,P)


DSR: Route discovery (8)EGMHRFABCIDSKNLPJQRREP(S,E,G,J,D)


DSR: Route Discovery (9)Route reply by reversing the route (as illustrated) works only if all the links along the route are bidirectionalIf unidirectional links are allowed, then RREP may need a route discovery from D to SNote: IEEE 802.11 assumes that links are bidirectional


DSR: Data deliveryEGMHRFABCIDSKNLPJQDATA(S,E,G,J,D)


DSR: Route maintenance (1)EGMHRFABCIDSKNLPJQDATA(S,E,G,J,D)X


DSR: Route maintenance (2)EGMHRFABCIDSKNLPJQXRERR(G-J)When receiving the Route Error message (RERR), S removes the broken link from its cache.It then tries another route stored in its cache; if none, it initializes a new route discovery


DSR: Optimization of route discovery: route caching

Principle: each node caches a new route it learns by any meansExamplesWhen node S finds route (S, E, G, J, D) to D, it also learns route (S, E, G) to node GIn the same way, node E learns the route to DSame phenomenon when transmitting route repliesMoreover, routes can be overheard by nodes in the neighbourhoodHowever, route caching has its downside: stale caches can severely hamper the performance of the network


DSR: StrengthsRoutes are set up and maintained only between nodes who need to communicateRoute caching can further reduce the effort of route discoveryA single route discovery may provide several routes to the destination


DSR: WeaknessesRoute requests tend to flood the network and generally reach all the nodes of the networkBecause of source routing, the packet header size grows with the route lenghRisk of many collisions between route requests by neighboring nodes need for random delays before forwarding RREQSimilar problem for the RREP (Route Reply storm problem), in case links are not bidirectional

Note: Location-aided routing may help reducing the number of useless control messages


Ad Hoc On-Demand Distance Vector Routing (AODV)

As it is based on source routing, DSR includes source routes in data packet headersLarge packet headers in DSR risk of poor performance if the number of hops is highAODV uses a route discovery mechanism similar to DSR, but it maintains routing tables at the nodesAODV ages the routes and maintains a hop count AODV assumes that all links are bi-directional


AODV : Route discovery (1)EGMHRFABCIDSKNLPJQ


AODV : Route discovery (2)EGMHRFABCIDSKNLPJQNote: if one of the intermediate nodes (e.g., A) knows a route to D, it responds immediately to S: Route Request (RREQ)


AODV : Route discovery (3)EGMHRFABCIDSKNLPJQ: represents a link on the reverse path


AODV : Route discovery (6)MDKLPJEGHRFABCISNQ


AODV : Route discovery (7)MDKLPJEGHRFABCISNQ


AODV : Route reply and setup of the forward pathMDKLPJEGHRFABCISNQ: Link over which the RREP is transmitted: Forward path


Route reply in AODVIn case it knows a path more recent than the one previously known to sender S, an intermediate node may also send a route reply (RREP)The freshness of a path is assessed by means of destination sequence numbersBoth reverse and forward paths are purged at the expiration of appropriately chosen timeout intervals


AODV : Data deliveryMDKLPJEGHRFABCISNQDataThe route is not included in the packet header


AODV : Route maintenance (1)MDKLPJEGHRFABCISNQDataX


AODV : Route maintenance (2)MDKLPJEGHRFABCISNQXRERR(G-J)When receiving the Route Error message (RERR), S removes the broken link from its cache.It then initializes a new route discovery.


AODV: Destination sequence numbers

If the destination responds to RREP, it places its current sequence number in the packetIf an intermediate node responds, it places its record of the destinations sequence number in the packetPurpose of sequence numbers:Avoid using stale information about routesAvoid loops (no source routing!)


AODV : Avoiding the usage of stale routing tables SDABDSN(D) = 5: Forward pathSDABDSN(D) = 5DSN(D) = 81.2.SDABDSN(D) = 5DSN(D) = 83.RREQSDABDSN(D) = 5DSN(D) = 8RREP4.


AODV : Avoiding loopsABSDC: Forward path Assume there is a route between A and D; link S-D breaks; assume A is not aware of this, e.g. because RERR sent by S is lost Assume now S wants to send to D. It performs a RREQ, which can be received by A via path S-C-A Node A will reply since it knows a route to D via node B This would result in a loop (S-C-A-B-S) The presence of sequence numbers will let S discover that the routing information from A is outdated Principle: when S discovers that link S-D is broken, it increments its local value of DSN(D). In this way, the new local value will be greater than the one stored by A.X


AODV (unicast) : ConclusionNodes maintain routing information only for routes that are in active useUnused routes expire even when the topology does not changeEach node maintains at most one next-hop per destinationMany comparisons with DSR (via simulation) have been performed no clear conclusion so far


Dynamic source routing ISplit routing into discovering a path and maintaining a path

Discover a pathonly if a path for sending packets to a certain destination is needed and no path is currently available

Maintaining a pathonly while the path is in use one has to make sure that it can be used continuously

No periodic updates needed!


Dynamic source routing IIPath discoverybroadcast a packet with destination address and unique IDif a station receives a broadcast packetif the station is the receiver (i.e., has the correct destination address) then return the packet to the sender (path was collected in the packet)if the packet has already been received earlier (identified via ID) then discard the packetotherwise, append own address and broadcast packet sender receives packet with the current path (address list)

Optimizationslimit broadcasting if maximum diameter of the network is knowncaching of address lists (i.e. paths) with help of passing packetsstations can use the cached information for path discovery (own paths or paths for other hosts)


Interference-based routingRouting based on assumptions about interference between signalsS1N5N3N4N1N2R1R2N6N8S2N9N7


Examples for interference based routingLeast Interference Routing (LIR)calculate the cost of a path based on the number of stations that can receive a transmissionMax-Min Residual Capacity Routing (MMRCR)calculate the cost of a path based on a probability function of successful transmissions and interferenceLeast Resistance Routing (LRR)calculate the cost of a path based on interference, jamming and other transmissions

LIR is very simple to implement, only information from direct neighbors is necessary


A plethora of ad hoc routing protocolsFlatproactiveFSLS Fuzzy Sighted Link StateFSR Fisheye State RoutingOLSR Optimized Link State Routing Protocol (RFC 3626)TBRPF Topology Broadcast Based on Reverse Path ForwardingreactiveAODV Ad hoc On demand Distance Vector (RFC 3561)DSR Dynamic Source Routing (RFC 4728)DYMO Dynamic MANET On-demandHierarchicalCGSR Clusterhead-Gateway Switch RoutingHSR Hierarchical State RoutingLANMAR Landmark Ad Hoc RoutingZRP Zone Routing ProtocolGeographic position assistedDREAM Distance Routing Effect Algorithm for MobilityGeoCast Geographic Addressing and RoutingGPSR Greedy Perimeter Stateless RoutingLAR Location-Aided RoutingTwo promisingcandidates:OLSRv2 andDYMO


Further difficulties and research areasAuto-ConfigurationAssignment of addresses, function, profile, program, Service discoveryDiscovery of services and service providersMulticastTransmission to a selected group of receiversQuality-of-ServiceMaintenance of a certain transmission qualityPower controlMinimizing interference, energy conservation mechanismsSecurityData integrity, protection from attacks (e.g. Denial of Service)Scalability10 nodes? 100 nodes? 1000 nodes? 10000 nodes?Integration with fixed networks


Clustering of ad-hoc networksInternetSuper clusterClusterBase stationCluster head


The next step: Wireless Sensor Networks (WSN)Commonalities with MANETsSelf-organization, multi-hopTypically wireless, should be energy efficient

Differences to MANETsApplications: MANET more powerful, more general WSN more specificDevices: MANET more powerful, higher data rates, more resources WSN rather limited, embedded, interacting with environmentScale: MANET rather small (some dozen devices) WSN can be large (thousands)Basic paradigms: MANET individual node important, ID centric WSN network important, individual node may be dispensable, data centricMobility patterns, Quality-of Service, Energy, Cost per node Example:www.scatterweb.net


Properties of wireless sensor networksSensor nodes (SN) monitor and control the environmentNodes process data and forward data via radioIntegration into the environment, typically attached to other networks over a gateway (GW)Network is self-organizing and energy efficientPotentially high number of nodes at very low cost per node

SNGWSNSNSNSNSNSNSNSNSNSNGWGWGWBluetooth, TETRA, EthernetSNGPRSWLANALARM!


Promising applications for WSNsMachine and vehicle monitoringSensor nodes in moveable partsMonitoring of hub temperatures, fluid levels

Health & medicineLong-term monitoring of patients with minimal restrictionsIntensive care with relative great freedom of movement

Intelligent buildings, building monitoringIntrusion detection, mechanical stress detectionPrecision HVAC with individual climate

Environmental monitoring, person trackingMonitoring of wildlife and national parksCheap and (almost) invisible person monitoringMonitoring waste dumps, demilitarized zones

and many more: logistics (total asset management, RFID), telematics WSNs are quite often complimentary to fixed networks!


Prof. Dr.-Ing. Jochen H. Schiller cst.mi.fu-berlin.de 2008-03-12Sensor Networks: Research AreasReal-World IntegrationGaming, TourismEmergency, RescueMonitoring, Surveillance

Self-configuring networksRobust routingLow-power data aggregationSimple indoor localization

Managing wireless sensor networksTools for access and programmingUpdate distribution

Long-lived, autonomous networksUse environmental energy sourcesEmbed and forget


WSN: Earthquake detectionThe occurrence of an earthquake can be detected automatically by accelerometers. Earthquake speed: around 5-10km/sIf the epicenter of an earthquake is in an unpopulated area 200km from a city center, an instantaneous detection system can give a warning up to 30 seconds before the shockwave hits the city.If a proper municipal actuation network is in place:Sirens go offTraffic lights go to redElevators open at the nearest floorPipeline valves are shutEven with a warning of a few seconds, the effects of the earthquake can be mitigated.Similar concept can be applied to Forest fireLandslidesEtc.C.S. Raghavendra, K.M. Sivalinguam and T. Znati Editors. Wireless Sensor Networks. Springer, 2006


WSN: Cold Chain ManagementSupermarket chains need to track the storage temperature of perishable goods in their warehouses and stores.Tens if not hundreds of fridges should be monitored in real-timeWhenever the temperature of a monitored item goes above a thresholdAn alarm is raised and an attendant is warned (pager, SMS)The refrigeration system is turned onHistory of data is kept in the system for legal purpose

Similar concept can be applied to pressure and temperature monitoring inProduction chainsContainersPipelines www.ip01.com


WSN: Home automationTemperature managementMonitor heating and cooling of a building in an integrated wayTemperature in different rooms is monitored centrally A power consumption profile is to be drawn in order to save energy in the future

Lighting management:Detect human presence in a room to automatically switch lights on and offResponds to manual activation/ deactivation of switchesTracks movement to anticipate the activation of light-switches on the path of a person

Similar concept can be applied toIntrusion detection


WSN: Precision Agriculture managementFarming decisions depend on environmental data (typically photo-synthesis):Solar radiationTemperatureHumiditySoil moisture

These data evolve continuously over time and spaceA farmers means of action to influence crop yield :IrrigationFertilizationPest treatmentTo be optimal, these actions should be highly localized (homogenous parcels can be as small as one hectare or less)Environmental impact is also to be taken into accountSalinization of soilsGroundwater depletionWell contamination


Routing in WSNs is differentNo IP addressing, but simple, locally valid IDsExample: directed diffusionInterest MessagesInterest in sensor data: Attribute/Value pairGradient: remember direction of interested nodeData MessagesSend back data using gradientsHop count guarantees shortest path

Sink


Energy-aware routingOnly sensors with sufficient energy forward data for other nodesExample: Routing via nodes with enough solar power is considered for free


Solar-aware routingSolar-powered nodeSend status updates to neighborsEither proactive or when sniffing ongoing trafficHave neighbor nodes reroute the traffic


Many different stepsWalkingAt least one foot on the groundLow step frequency

RunningPeriods without ground contactSimilar to jumpingHigher step frequency, wider steps

SprintingSimilar to runningHighest step frequencyOnly short distances

What about crawling, jumping, stumbling


The Future of WSNsFundamental requirements today only partially fulfilledLong life-time with/without batteriesSelf-configuring, self-healing networksRobust routing, robust data transmissionManagement and integration

Think of new applicationsIntelligent environments for gaming

Still a lot to doIntegration of new/future radio technologiesCheap indoor localization (+/- 10cm)More system aspects (security, middleware, )Prove scalability, robustnessMake it cheaper, simpler to use

Already today: Flexible add-on for existing environmental monitoring networks


Universitt KarlsruheInstitut fr TelematikUniversitt KarlsruheInstitut fr TelematikMobilkommunikationSS 1998Prof. Dr. Dr. h.c. G. KrgerE. Dorner / Dr. J. Schiller*Prof. Dr. Dr. h.c. G. KrgerE. Dorner / Dr. J. SchillerUniversitt KarlsruheInstitut fr TelematikUniversitt KarlsruheInstitut fr TelematikMobilkommunikationSS 1998Prof. Dr. Dr. h.c. G. KrgerE. Dorner / Dr. J. Schiller*Prof. Dr. Dr. h.c. G. KrgerE. Dorner / Dr. J. SchillerUniversitt KarlsruheInstitut fr TelematikUniversitt KarlsruheInstitut fr TelematikMobilkommunikationSS 1998Prof. Dr. Dr. h.c. G. KrgerE. Dorner / Dr. J. Schiller**Prof. Dr. Dr. h.c. G. KrgerE. Dorner / Dr. J. SchillerUniversitt KarlsruheInstitut fr TelematikUniversitt KarlsruheInstitut fr TelematikMobilkommunikationSS 1998Prof. Dr. Dr. h.c. G. KrgerE. Dorner / Dr. J. Schiller**Prof. Dr. Dr. h.c. G. KrgerE. Dorner / Dr. J. SchillerUniversitt KarlsruheInstitut fr TelematikUniversitt KarlsruheInstitut fr TelematikMobilkommunikationSS 1998Prof. Dr. Dr. h.c. G. KrgerE. Dorner / Dr. J. Schiller**Prof. Dr. Dr. h.c. G. KrgerE. Dorner / Dr. J. SchillerUniversitt KarlsruheInstitut fr Telematik*Prof. Dr. Dr. h.c. G. KrgerE. Dorner / Dr. J. SchillerUniversitt KarlsruheInstitut fr Telematik*Prof. Dr. Dr. h.c. G. KrgerE. Dorner / Dr. J. SchillerUniversitt KarlsruheInstitut fr Telematik*Prof. Dr. Dr. h.c. G. KrgerE. Dorner / Dr. J. SchillerUniversitt KarlsruheInstitut fr Telematik*Prof. Dr. Dr. h.c. G. KrgerE. Dorner / Dr. J. SchillerUniversitt KarlsruheInstitut fr TelematikUniversitt KarlsruheInstitut fr TelematikMobilkommunikationSS 1998Prof. Dr. Dr. h.c. G. KrgerE. Dorner / Dr. J. Schiller*Interest MessagesInterest in sensor data: Attribute/Value pairGradient: remember direction of interested node Data MessagesSend back data using gradientsHop count guarantees shortest path

Prof. Dr. Dr. h.c. G. KrgerE. Dorner / Dr. J. SchillerUniversitt KarlsruheInstitut fr TelematikUniversitt KarlsruheInstitut fr TelematikMobilkommunikationSS 1998Prof. Dr. Dr. h.c. G. KrgerE. Dorner / Dr. J. Schiller*Energy Battery-driven nodesSome nodes with permanent power supplySolar cells

Implications of using solar energyRouting across solar-powered nodes freeBUT: Sun is moving...

Integrate solar-awareness in routingProf. Dr. Dr. h.c. G. KrgerE. Dorner / Dr. J. SchillerUniversitt KarlsruheInstitut fr TelematikUniversitt KarlsruheInstitut fr TelematikMobilkommunikationSS 1998Prof. Dr. Dr. h.c. G. KrgerE. Dorner / Dr. J. Schiller*Statusleiste erklrenProf. Dr. Dr. h.c. G. KrgerE. Dorner / Dr. J. SchillerUniversitt KarlsruheInstitut fr TelematikUniversitt KarlsruheInstitut fr TelematikMobilkommunikationSS 1998Prof. Dr. Dr. h.c. G. KrgerE. Dorner / Dr. J. Schiller*Gehen:-zweiter Fu sttzt den Krper-f

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C08 Network Protocols

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