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Transcript
Enabling a complementary connection-oriented internet Malathi Veeraraghavan Univ. of Virginia [email protected] • Outline • • • • Bandwidth sharing in connection-oriented networks Specific problems Why do it? Hasn’t this been attempted before? Talk at NSF workshop, Santa Barbara, CA, April 12-13, 2005 1 What our optical devices colleagues have achieved so far Communications link technology • optical Multiplexing technology • DWDM Tx/Rx Communication link Network • Switches Switching modes Tx/Rx Switch optical switches Position-based switching (circuit switching) Connection-oriented (CO) networking mode Header-data based switching Continue working (packet switching) 2 Interdependence Needs support NOW Research that leads to new communications applications GMPLS protocols Research that leads to networking software we like packet switches Optical circuit switches Research that leads to networking hardware make faster switching devices DWDM Research that leads to communication link and switching devices 3 Spectrum of options Our optical communication technology colleagues are taking us in this direction Point-to-point always-up high-capacity links; George Glider world of completely free bandwidth - no role for networking Our kids are taking us in the opposite direction Dynamically shared circuits; Leverage increased bandwidth offered by fiber and DWDM; increased service quality for some wasted bandwidth Bandwidth is expensive; Share it to the hilt; Hence packet switching 4 Focus of this talk • Networking “software” research – Do something useful with the optical circuit switches created by our hardware colleagues • Optical circuit switches implies – Research on connection-oriented (CO) mode – Where should the focus be within this context? 5 Bandwidth sharing: the very reason for the existence of networks (switches) • Research issues in bandwidth sharing in CO networks? – Protocols for running the network completely with software and hardware • humans just hang out and watch and interfere if something goes wrong – Algorithms • when do you accept a request for bandwidth reservation? when do you reject? when do you give less than the requested bandwidth; how much less? • use of Markov Decision Processes – trade off fairness for utilization • how to handle advance reservations for large durations or large bandwidth in conjunction with small duration or small bandwith calls 6 Current work • Protocols for running the CO network completely with software and hardware (minimal humans) – GMPLS protocols 7 GMPLS protocols • Triumvirate to build large-scale networks in “plug-and-play” mode – LMP to discover neighbors – OSPF-TE for routing – RSVP-TE for signaling • Should be able to create distributed large-scale networks with “minimal” admin support 8 Amazingly! • Standards quite advanced • Implementations exist! – Switch vendors haven’t waited for business cases to implement these protocols 9 Even more amazing! • Deployed routers and switches now have the latest versions of software releases that include GMPLS protocols – – – – Cisco and Juniper routers (MPLS/RSVP) Sycamore and Ciena SONET switches Movaz, Calient(?) WDM switches With Dragon’s help, Ethernet switches can be run in CO mode 10 But now • Commercial service providers – Are waiting for business cases to simply flick the switch – “turn on” RSVP; “turn on” MPLS in routers/switches – Chicken-and-egg problem: apps. and switch features • Research network administrators – Internet2, DoE’s ESnet are “afraid” to turn these on 11 Need to fund researchers to • Discover if there’s something to be “scared” of • TESTBEDS! – Look at investments in Canada, Japan, Europe – It’s a shame – we are wasting the work of our optical device colleagues and our GMPLS engineers 12 Well, hasn’t this happened before? • What about our ATM devices/hardware colleagues’ hard efforts? • ATM networking software researchers created the protocols • Apps were experimented with in universities; trials were run by service providers • Didn’t take off. Why? • Do we give up? Are we saying Connectionless packet-switched networking is the only way to build networks? 13 I don’t think so • Two reasons – MIPs for processors, MB for memory, ?? for a network service – Analogy with transportation modes 14 Reason 1 • Purpose of a communication link and by extension a communication network – To provide connectivity between a data sending entity and a data receiving entity – Quantify connectivity • bandwidth is a primary measure – Shouldn’t we have a network that provides users specific bandwidth levels as and when requested? 15 Reason 2 • Analogy with people/goods transportation modes – unreserved travel: roadways – reserved travel: airline seat • So what breaks down in the analogy for types of networks moving data? – we only have roadways now 16 So look for ideas from researchers on what pitfalls are being avoided in their proposals ATM Homogeneous CO network Required new deployment of switches First, aimed for end-to-end network: • fiber-to-desktop; • ATM NICs Then went for a partial-ATM solution (Ethernet/IP enterprise networks + ATM WAN) • Required egress routers to do flow classification • Thinking: if no CO userplane at end host, then no use for signaling at the end host Heterogeneous CO internet Use already deployed switches (leverage Internet2, ESnet, VLANs) Allow partial connections • But have end host signal its desire to reserve bandwidth • Avoid all those issues of RSVP not scaling • who says all flows need to reserve bandwidth 17 Partial path reservations • Ipsilon’s IP switch Call to make a reservation (if only for part of the distance: airport-to-airport) – Flow classification at “airport” to trigger connection setup – Questions of scalability – notion of having to hold “state” information for millions of flows • No, just the ones who requested bandwidth CL network CO network airport airport 18 Specific problems • End-to-end heterogeneous connections – VLAN capability in Ethernet switches makes this economically possible • Partial connections – Peel off slice of bandwidth on congested link for connections – for delay-sensitive apps (Internet gaming, etc.) • Use MDP to determine Virtual Partitioning limits for sharing a link between CL service and CO service • Billing – fairness/util. algorithms + implementation 19 CO networking research focus • Then has to center around – Applications & Testbeds – Algorithms – Protocols – Architectures – Implementations that need/enable dynamic sharing of bandwidth • And have to think large-scale – The value of the network grows exponentially with the number of endpoints 20 Summary • Near-term: • Fund CO networking research • Optical circuit switches with GMPLS already here • Long-term: • Fund optical switching devices and networking hardware research to make optical packet switches, burst switches • Fund optical comm. technology work to keep pushing bandwidth higher • Seems that there’s a capacity glut now but if our kids have their say, we’ll soon need more 21