Modest networking Henning Schulzrinne Columbia University MIND Workshop – London, Oct. 7, 2002 Keynote Address Joint work with Maria Papadopouli Hannes Tschofenig Xiaoming Fu Jochen Eisl Robert Hancock* (Opinions are the speaker’s and may not be shared by the co-authors…)

Overview New Realism in networking Multimodal networking Some thoughts on QoS CASP – another attempt at QoS signaling

New realism Old notion: build it and they will pay “Don’t want to be just dumb bit carriers’’ Value add  charge exorbitant fees for shipping special bits Convergence  all bits are similar Cheapest bits win (unless monopolies or regulation interfere) Almost all of networking is/will be a commodity – we should be proud of it!

Cost of networking Modality modespeed $/MB (= 1 minute of 64 kb/s videoconferencing or 1/3 MP3) OC-3P 155 Mb/s $ Australian DSL (512/128 kb/s) P 512/128 kb/s $0.018 GSM voiceC 8 kb/s $0.66-$1.70 HSCSDC 20 kb/s $2.06 GPRSP 25 kb/s $4-$10 IridiumC 10 kb/s $20 SMS (160 chars/message) P ? $62.50 Motient (BlackBerry) P 8 kb/s $133

Spectrum cost for 3G Location whatcost UK3G$590/person Germany3G$558/person Italy3G$200/person New YorkVerizon (20MHz) $220/customer Generally, license limited to years

Multimodal networking = use multiple types of networks, with transparent movement of information technical integration (IP)  access/business integration (roaming) variables: ubiquity, access speed, cost/bit, … 2G/3G: rely on value of ubiquity immediacy but: demise of Iridium and other satellite efforts similar to early wired Internet or some international locations e.g., Australia

Multimodal networking expand reach by leveraging mobility locality of data references mobile Internet not for general research Zipf distribution for multimedia content short movies, MP3s, news, … newspapers local information (maps, schedules, traffic radio, weather, tourist information)

Multimedia data access modalities highlow high7DS hotspots lowsatellite SMS? voice (2G, 2.5G) bandwidth (peak) delay

A family of access points Infostation 2G/3G access sharing 7DS hotspot + cache WLAN

7DS options Many degrees of cooperation server to client only server shares data no cooperation among clients fixed and mobile information servers peer-to-peer data sharing and query forwarding among peers

7DS options Query Forwarding Host AHost B query FW query Host C time Querying active (periodic) passive Power conservation on off time communication enabled

high transmission power 2 Fixed Info Server Mobile Info Server P2P Dataholders (%) after 25 min

Host B Message relaying Host A messages Gateway WAN Host A WLAN Message relaying with 7DS

Quality of Service

Why QoS hasn’t happened need to admit failure – “bandwidth too cheap to meter” undemocratic: some traffic is more equal than other dishonest: we only talk about the beneficiaries reminds you of your mom: no, you can’t have that 10 Mb/s now socialist: administer scarcity - we like SUVs (or to drive 100 mph)! “risky scheme”: security exposure – reserve your whole network niche only: displacement applications (such as telephony) need QoS touchy-feely: requires cooperation  edge-ISP, transit ISPs, end systems snake oil: add QoS, lose half your router interface bandwidth

What makes QoS hard No, it’s not RSVP scaling network has become harder to evolve: network address translation firewalls high packetization overhead (VPNs, IPv6) nobody can be trusted to be useful, has to be nearly universally supported (“no, you can’t make calls to AS 123”) network QoS vs. business class model: “coach is empty, please refund fare” almost all the time, reserved traffic gets same delay as best effort applications will switch QoS classes

What makes QoS hard currently, the ISP interface is IP and BGP – adding a third one is a big deal trust model  ISP or cash model payment model completely unclear for peering new Internet service model: TCP client (inside) – server (outside) exception: peer-to-peer on college campuses network to host: you first, no, you first

What is QoS, really? Network transparency no loss (< 1%) very few delay spikes (< 1%) close to propagation delay anything else is too hard to explain to users! QoS is just a facet of network reliability consistent 5% packet loss is much better than 5% probability that network is unavailable for seconds users are willing to pay for availability traditional QoS may help availability during outage periods e.g., MCI/UUnet breakdown 10/3/02 DOS attacks failure of load distribution links

CASP = Cross-Application Signaling Protocol RSVP is being used for lots of things beyond flow setup: RSVP TE, midcom, … Complex and monolithic multicast support  multiple reservation styles killer reservations and error handling receiver-orientation only non-RSVP region handling interface complexity (LIH) fairly closely ties QoS to RSVP hard to extract generic signaling protocols  CASP as modular signaling protocol currently a proposal for IETF NSIS group

What is CASP? Generic signaling service establishes state along path of data one sender, typically one receiver can be multiple receivers  multicast can be used for QoS per-flow or per-class reservation also: firewall setup, TE, programmable networks, configuration, topology exploration, … avoid restricting users of protocol (and religious arguments): sender vs. receiver orientation more or less closely tied to data path router-by-router network (AS)

CASP network model – on- path CASP nodes form CASP chain not every node processes all client protocols: non-CASP node: regular router omnivorous: processes all CASP messages selective: bypassed by CASP messages with unknown client protocols QoS midcom QoS selective omnivorous CASP chain

CASP network model – out-of- path Also route network-by-network can combine router-by-router with out- of-path messaging AS 1249 AS15465 AS17 Bandwidth broker NAC CASP data

CASP protocol structure client layer does the real work: reserve resources open firewall ports … messaging layer: establishes and tears down state negotiates features and capabilities transport layer: reliable transport client layer (C) messaging layer (M) transport layer (T) scout protocol UDP IP router alert messaging layer (M) CASP

Next-hop discovery Next-in-path service enhanced routing protocols  distribute information about node capabilities in OSPF routing protocol with probing service discovery, e.g., SLP first hop, e.g., router advertisements DHCP scout protocol Next AS service touch down once per autonomous system (AS) new DNS name space: ASN.as.arpa, e.g., 17.as.arpa use new DNS NAPTR and SRV for lookup similar to SIP approach

Mobility and route changes avoids session identification by end point addresses avoid use of traffic selector as session identifier remove dead branch discovers new route on refresh ADD B=2 DEL (B=2) B=1

Conclusion Until wireless bits are too cheap to meter, try hiding lack of universal high bit density from user QoS is a reliability mechanism CASP as a new signaling platform