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Networking challenges. Henning Schulzrinne Dept. of Computer Science Columbia University New York, NY. Networks beyond the Internet, cont’d. More than just Internet Classic . Myth #1: Addresses are global & constant. also: identifier-locator split. - PowerPoint PPT Presentation

Transcript of Networking challenges

Distributed Self Fault-Diagnosis for SIP Multimedia Applications

Networking challengesHenning SchulzrinneDept. of Computer ScienceColumbia UniversityNew York, NYInterDigital June 20091Networks beyond the Internet, contdInterDigital June 2009Network modelroute stabilitymotion of data routersInternetminutesunlikelymobile ad-hoc3 disruptivestore-carry-forward< 3 helpfulMore than just Internet Classic Networkwirelessmobilitypath stabilitydata unitsInternet classiclast hopend systems> hoursIP datagramsmesh networksall linksend systems> hoursmobile ad-hocall linksall nodes, randomminutesopportunistictypicalsingle node minutedelay-tolerantall linkssome predictablesome predictablebundlesstore-carry-forwardall nodesall nodesno pathapplication data unitsInterDigital June 2009

Myth #1: Addresses are global & constantInterDigital June 2009


STUN1.2.3.4also: identifier-locator splitMyth #2: Connectivity commutes, associatesReferals, call-backs, redirectsAssumptions:A connects to B B can connect to AA connects to B, B to C C can connect to AMay be time-dependentInterDigital June 2009

200 ms

Myth #2a: Bidirectional connectivityInterDigital June 2009

Myth #3: End-to-end delay of 1st packet typical1st packet may have additional latencyARP, flow-based routersMIPv6, PIM-SM, MSDP: fixed path during initial data burst Choice of server may be suboptimalhigher delay, lower throughput, inefficient network usage

InterDigital June 2009

ChallengesInterDigital June 2009User challenges vs. research challengesAre we addressing real user needs?Engineering vs. sportsMy guessesInterDigital June 2009reliabilityease of usecostno manualintegrationlimited riskphishingdata lossno re-entryno duplication9Cause of death for the next big thingInterDigital June 2009QoSmulti-castmobile IPactive networksIPsecIPv6not manageable across competing domainsnot configurable by normal users (or apps writers)no business model for ISPsno initial gain80% solution in existing system (NAT)increase system vulnerability10Which Internet are you connected to?InterDigital June 2009multicastQoSIPv6IPv4PIAIPv4DHCPIPv4NATport 80 + 25Network challengesInterDigital June 2009

routing tableexplosion

multi-homing99.9 99.999%

zero configuration+2 years+5 years+8 years multihomingInterDigital June 2009Network of the (near) futureInterDigital June 2009

MSOTelco3G, 4G, WiMaxHomes passed by multiple networks increase reliability by connecting to all(reliable system out of unreliable components)Multihoming (& mobility) Current IPv4 address identifier = unique host or interfacelocator = network that serves host (provider)One system, multiple addresses:multihoming: at the same timemobility: sequentiallyMultihoming:connections need to be aware of network pathsocket interface makes it hard to programSolutions:HIP: cryptographic host identifierSHIM6LISP: two network addressesDNS: SRV, NAPTRInterDigital June 2009Example: BGP growthInterDigital June 2009 June 2009Network security issuesInterDigital June 2009What about security?InterDigital June 20099: Political8: FinancialApplicationPresentationSessionTransportNetworkLinkPhysical

Technologies (mostly) available, but use & deployment hardsecure DNSsecure BGPpasswords certs + crypto token

usablesecurityconfigurationWhat about security?The future Internet must be secureMost security-related problems are not network problemsspam: identity and access, not SMTPweb: (mostly) not TLS, but distinguishing real bank from fake oneweb: cross-domain scripting, code injectionbrowser vulnerabilities & keyboard sniffersRestrict generalityBlack list white listvirus checker app storeAutomated toolsbetter languages, taint tracking, automated input checking, stack protection, memory randomization, Probably need more trust mediation

InterDigital June 2009Ad-hoc networksDefinition: (all/most) nodes relay dataevery node a routerunlike P2P: layer 2/3like P2P: grow organically, no central administrationClassical problems:routing problems with unstable linkspro-active and reactivegeographic routingenergy usagefor non-vehicular networkslocation determinationInterDigital June 2009Ad-hoc, sensor and mesh networksInterDigital June 2009mesh(nodes as routers)sensor(processing, energy)mobile ad-hoc(links vanish, energy)vehicular(single-hop?)Ad-hoc networksThousands of papersrouting, security, transport, PHY, Unclear applicabilityniche applications in industrial and home controlZigBeecellular backhaul?others mostly single-hopbandwidth constraints of mesh networksInterDigital June 2009MobilityIETF workproxy mobile IPv6now: NETEXTNETLMN (local mobility)Other:lots of stages optimizing hand-off (see Dutta et al.)application-layer hand-offmost applications dont need address stabilityuse of multiple interfaces?interaction with cognitive radio?InterDigital June 20097DS and opportunistic networks: exploring networks beyond the Internetwith Suman Srinivasan, Arezu MoghadamInterDigital June 2009



DContacts areopportunisticintermittent 802.11 ad-hoc modeBlueTooth

InterDigital June 200926Therefore these networks have unique characteristics and introduce new challenges from the networking basics to the applicationsTHERE IS NO END-TO-END PATH.Web Delivery Model

InterDigital June 20097DS core functionality: Emulation of web content access and e-mail delivery

Search EngineProvides ability to query self for resultsSearches the cache index using Swish-e libraryPresents results in any of three formats: HTML, XML and plain textSimilar in concept to Google Desktop

InterDigital June 2009

Email exchange

InterDigital June 2009BonAHA frameworkInterDigital June 2009Node 2Node 1key21 = value21key22 = value22key23 = value23key24 = value24key11 = value11key12 = value12key13 = value13key14 = value14

[2] node1.get(key13)[1] node1.register()[3] data = node1.fileGet( value13);

BonAHA[CCNC 2009]

Bulletin Board System

InterDigital June 2009Written in Objective-C, for iPod Touch