1. Standardization Henning Schulzrinne Dept. of Computer Science Columbia University Fall 2003

2. 2 Time Line of the Internet Source: Internet Society

3. Standards Mandatory vs. voluntary – Allowed to use vs. likely to sell – Example: health & safety standards  UL listing for electrical appliances, fire codes Telecommunications and networking always focus of standardization – 1965: International Telegraph Union (ITU) – 1956: International Telephone and Telegraph Consultative Committee (CCITT) Five major organizations: – ITU for lower layers, multimedia collaboration – IEEE for LAN standards (802.x) – IETF for network, transport & some applications – W3C for web-related technology (XML, SOAP) – ISO for media content (MPEG)

4. Who makes the rules? - ITU ITU = ITU-T (telecom standardization) + ITU-R (radio) + development – http://www.itu.int http://www.itu.int – 14 study groups – produce Recommendations: E: overall network operation, telephone service (E.164) G: transmission system and media, digital systems and networks (G.711) H: audiovisual and multimedia systems (H.323) I: integrated services digital network (I.210); includes ATM V: data communications over the telephone network (V.24) X: Data networks and open system communications Y: Global information infrastructure and internet protocol aspects

5. ITU Initially, national delegations Members: state, sector, associate – Membership fees (> 10,500 SFr) Now, mostly industry groups doing work Initially, mostly (international) telephone services Now, transition from circuit-switched to packet- switched universe & lower network layers (optical) Documents cost SFr, but can get three freebies for each email address

6. IETF IETF (Internet Engineering Task Force) – see RFC 3233 (“Defining the IETF”) Formed 1986, but earlier predecessor organizations (1979-) RFCs date back to 1969 Initially, largely research organizations and universities, now mostly R&D labs of equipment vendors and ISPs International, but 2/3 United States – meetings every four months – about 300 companies participating in meetings but Cisco, Ericsson, Lucent, Nokia, etc. send large delegations

7. IETF Supposed to be engineering, i.e., translation of well-understood technology  standards – make choices, ensure interoperability – reality: often not so well defined Most development work gets done in working groups (WGs) – specific task, then dissolved (but may last 10 years…) – typically, small clusters of authors, with large peanut gallery – open mailing list discussion for specific problems – interim meetings (1-2 days) and IETF meetings (few hours) – published as Internet Drafts (I-Ds) anybody can publish draft-somebody-my-new-protocol also official working group documents (draft-ietf-wg-*) versioned (e.g., draft-ietf-avt-rtp-10.txt) automatically disappear (expire) after 6 months

8. IETF process WG develops  WG last call  IETF last call  approval (or not) by IESG  publication as RFC IESG (Internet Engineering Steering Group) consists of area directors – they vote on proposals – areas = applications, general, Internet, operations and management, routing, security, sub-IP, transport Also, Internet Architecture Board (IAB) – provides architectural guidance – approves new working groups – process appeals

9. IETF activities general (3): ipr, nomcom, problem applications (25): crisp, geopriv, impp, ldapbis, lemonade, opes, provreg, simple, tn3270e, usefor, vpim, webdav, xmpp internet (18) = IPv4, IPv6, DNS, DHCP: dhc, dnsext, ipoib, itrace, mip4, nemo, pana, zeroconf oam (22) = SNMP, RADIUS, DIAMETER: aaa, v6ops, netconf, … routing (13): forces, ospf, ssm, udlr, … security (18): idwg, ipsec, openpgp, sasl, smime, syslog, tls, xmldsig, … subip (5) = “layer 2.5”: ccamp, ipo, mpls, tewg transport (26): avt (RTP), dccp, enum, ieprep, iptel, megaco, mmusic (RTSP), nsis, rohc, sip, sipping (SIP), spirits, tsvwg

10. RFCs Originally, “Request for Comment” now, mostly standards documents that are well settled published RFCs never change always ASCII (plain text), sometimes PostScript anybody can submit RFC, but may be delayed by review (“end run avoidance”) see April 1 RFCs (RFC 1149, 3251, 3252) accessible at http://www.ietf.org/rfc/ and http://www.rfc-editor.org/http://www.ietf.org/rfc/

11. IETF process issues Can take several years to publish a standard – see draft-ietf-problem-issue-statement Relies on authors and editors to keep moving – often, busy people with “day jobs”  spurts three times a year Lots of opportunities for small groups to delay things Original idea of RFC standards-track progression: – Proposed Standard (PS) = kind of works – Draft Standard (DS) = solid, interoperability tested (2 interoperable implementations for each feature), but not necessarily widely used – Standard (S) = well tested, widely deployed

12. IETF process issues Reality: very few protocols progress beyond PS – and some widely-used protocols are only I-Ds In addition: Informational, Best Current Practice (BCP), Experimental, Historic Early IETF: simple protocols, stand-alone – TCP, HTTP, DNS, BGP, … Now: systems of protocols, with security, management, configuration and scaling – lots of dependencies  wait for others to do their job

13. Other Internet standards organizations ISOC (Internet Society) – legal umbrella for IETF, development work IANA (Internet Assigned Numbers Authority) – assigns protocol constants NANOG (North American Network Operators Group) (http://www.nanog.org)http://www.nanog.org – operational issues – holds nice workshop with measurement and “real world” papers RIPE, ARIN, APNIC – regional IP address registries  dole out chunks of address space to ISPs – routing table management

14. ICANN Internet Corporation for Assigned Names and Numbers – manages IP address space (at top level) – DNS top-level domains (TLD) ccTLD: country codes (.us,.uk, …) gTLDs (.com,.edu,.gov,.int,.mil,.net, and.org) uTLD (unsponsored):.biz,.info,.name, and.pro sTLD (sponsored):.aero,.coop, and.museum actual domains handled by registrars

15. Modern Internet architecture & technology Advanced Internet Services Dept. of Computer Science Columbia University Henning Schulzrinne Fall 2003

16. Internet applications Variations on three themes – distinguish protocol vs. application behavior Messaging – datagram model  no direct confirmation of final receipt – email (optional confirmation now) and IM – emphasis on interoperation (SMS, pagers, …) – delays measured in minutes Retrieval & query (request/response) – “client-server” – ftp, HTTP – RPC (Sun RPC, DCE, DCOM, Corba, XML-RPC, SOAP) – emphasis on fast & reliable transmission – delays measured in seconds

17. Internet applications, cont’d Continuous media – generation rate ~ delivery rate ~ rendering rate – audio, video, measurements, control Internet telephony Multimedia conferencing – related: streaming media  slightly longer timescales for rate matching video-on-demand – emphasis is on timely and low-loss delivery  real-time – delays measured in milliseconds – focus of this course

18. Internet protocols Protocols support these applications: – data delivery HTTP, ftp data part, SMTP, IMAP, POP, NFS, SMB, RTP – identifier mapping (id  id, id  data) ARP, DNS, LDAP – configuration (= specialized version of identifier  data) DHCP, ACAP, SLP, NETCONF, SNMP – control and setup RTSP, SIP, ftp control, RSVP, SNMP, BGP and routing protocols May be integrated into one protocol or general service function (“middleware”?)

19. Networking is getting into middle years ideacurrent IP1969, 1980?1981 TCP19741981 telnet19691983 ftp19801985

20. Standardization Really two facets of standardization: 1. public, interoperable description of protocol, but possibly many (Tanenbaum) 2. reduction to 1-3 common technologies LAN: Arcnet, tokenring, ATM, FDDI, DQDB, …  Ethernet WAN: IP, X.25, OSI  IP Have reached phase 2 in most cases, with RPC (SOAP) and presentation layer (XML) most recent 'conversions'

21. Technologies at ~30 years Other technologies at similar maturity level: – air planes: 1903 – 1938 (Stratoliner) – cars: 1876 – 1908 (Model T) – analog telephones: 1876 – 1915 (transcontinental telephone) – railroad: 1800s -- ?

22. Observations on progress 1960s: military  professional  consumer – now, often reversed Oscillate: convergence  divergence – continued convergence clearly at physical layer – niches larger  support separate networks Communications technologies rarely disappear (as long as operational cost is low): – exceptions: telex, telegram, semaphores  fax, email X.25 + OSI, X.400  IP, SMTP – analog cell phones

23. History of networking History of networking = non-network applications migrate – postal & intracompany mail, fax  email, IM – broadcast: TV, radio – interactive voice/video communication  VoIP – information access  web, P2P – disk access  iSCSI, Fiberchannel-over-IP

24. Network evolution Only three modes, now thoroughly explored: – packet/cell-based – message-based (application data units) – session-based (circuits) Replace specialized networks – left to do: embedded systems need cost(CPU + network) < $10 cars industrial (manufacturing) control commercial buildings (lighting, HVAC, security; now LONworks) remote controls, light switches keys replaced by biometrics

25. New applications New bandwidth-intensive applications – Reality-based networking – (security) cameras Distributed games often require only low-bandwidth control information – current game traffic ~ VoIP Computation vs. storage vs. communications – communications cost has decreased less rapidly than storage costs

26. Commercial access cost (T1)

27. Transit cost (OC-3, NY – London)

28. Disk storage cost (IDE)

29. Transition of networking Maturity  cost dominates – can get any number of bits anywhere, but at considerable cost and complexity – casually usable bit density still very low Specialized  commodity – OPEX (= people) dominates – installed and run by 'amateurs' – need low complexity, high reliability

30. Security challenges DOS, security attacks  permissions-based communications – only allow modest rates without asking – effectively, back to circuit-switched Higher-level security services  more application- layer access via gateways, proxies, … User identity – problem is not availability, but rather over-abundance

31. Scaling Scaling is only backbone problem Depends on network evolution: – continuing addition of AS to flat space  deep trouble – additional hierarchy

32. Quality of Service (QoS) QoS is meaningless to users care about service availability  reliability as more and more value depends on network services, can't afford random downtimes

33. Textbook Internet vs. real Internet end-to-end (application only in 2 places) middle boxes (proxies, ALGs, …) permanent interface identifier (IP address) time-varying (DHCP) globally unique and routable network address translation (NAT) multitude of L2 protocols (ATM, ARCnet, Ethernet, FDDI, modems, …) dominance of Ethernet, but also L2’s not designed for networks ( 1394 Firewire, Fibre Channel, MPEG2, …)

34. Textbook Internet vs. real Internet mostly trusted end usershackers, spammers, con artists, pornographers, … small number of manufacturers, making expensive boxes Linksys, Dlink, Netgear, …, available at Radio Shack technical users, excited about new technology grandma, frustrated if email doesn’t work 4 layers (link, network, transport, application) layer splits transparent networkfirewalls, L7 filters, “transparent proxies”

35. Internet architecture documents (readings) http://www.ietf.org/rfc/rfcXXXX.txt RFC 1287 RFC 2101 RFC 2775 RFC 3234

36. email WWW phone... SMTP HTTP RTP... TCP UDP … IP ethernet PPP … CSMA async sonet... copper fiber radio... The Internet Protocol Hourglass (Deering)

37. Why the hourglass architecture? Why an internet layer? – make a bigger network – global addressing – virtualize network to isolate end-to-end protocols from network details/changes Why a single internet protocol? – maximize interoperability – minimize number of service interfaces Why a narrow internet protocol? – assumes least common network functionality to maximize number of usable networks Deering, 1998

38. email WWW phone... SMTP HTTP RTP... TCP UDP … IP + mcast + QoS +... ethernet PPP … CSMA async sonet... copper fiber radio... Putting on Weight requires more functionality from underlying networks

39. email WWW phone... SMTP HTTP RTP... TCP UDP … IP 4 IP 6 ethernet PPP … CSMA async sonet... copper fiber radio... Mid- Life Crisis doubles number of service interfaces requires changes above & below major interoper- ability issues

40. Layer splitting Traditionally, L2 (link), L3 (network = IP), L4 (transport = TCP), L7 (applications) Layer 2: Ethernet  PPPoE (DSL) Layer 2.5: MPLS, L2TP Layer 3: tunneling (e.g., GPRS) Layer 4: UDP + RTP Layer 7: HTTP + real application

41. Layer violations Layers offer abstraction  avoid “Internet closed for renovation” Cost of information hiding Cost of duplication of information when nothing changes – fundamental design choice of Internet = difference between circuit and datagram-oriented networks Assumption: packets are large and getting larger – wrong for games and audio Cost prohibitive on wireless networks – will see: 10 bytes of payloads, 40 bytes of packet header – header compression  compress into state index on one link

42. Internet acquires presentation layer All learn about OSI 7-layer model OSI: ASN.1 as common rendering of application data structures – used in LDAP and SNMP (and H.323) Internet never really had presentation layer – approximations: common encoding (TLV, RFC 822 styles) Now, XML as the design choice by default

43. Internet acquires session layer Originally, meant for data sessions Example (not explicit): ftp control connection Now, separate data delivery from session setup – address and application configuration – deal with mobility – will see as RTSP, SIP and H.323