T-110.5110 Computer Networks II Introduction 21.9.2009

1. T-110.5110 Computer Networks IIIntroduction21.9.2009 Prof. Sasu Tarkoma

2. Contents • Course Outline • Carrying out the course • Lectures • Material

3. Course Outline • 4 credit course • During Autumn 2009, we will look at protocols and architectures related to mobility management, session management, authentication, authorization and accounting (AAA) services and quality of service (QoS). • The course consists of the lectures and a final exam. • The purpose is that the participants actively read the material beforehand and discuss problem areas during the lectures. • Networks II lectures start on Monday 21.9. 14.15 - 16 in T2. Registration happens on this first lecture. Course material will be in English. Lectures will be in English if required.

4. Course Goals • Understand advanced networking techniques • Learn state of the art • Get a glimpse to near-future technologies and long haul development

5. Time and Place • Time and place: Mondays at 14:15 – 15:45 in T2. • Prof. Sasu Tarkoma gives the lecture unless otherwise indicated.

6. Carrying out the Course • The course grade consists of participation to lectures and a final exam. • Mandatory assignment: Wireshark • Final exams will be held as follows: • 17.12.2008 16:30-19:30 in T1. • Required preliminary knowledge • T-110.300 Telecommunication Architectures • T-110.350 Computer Networks • T-110.402 Information Security Technology

7. Lectures

8. Final Exam • 17.12.2008 16:30 – 19:30 T1 • Exam will be based on course material • Slides • Articles and standards documents • Essay questions

9. Material • General • Rethinking the design of the Internet: the end-to-end arguments vs. the brave new worldOn Compact Routing for the Internet authored by Dima Krioukov, kc claffy, Kevin Fall, and Arthur Brady. Published in the ACM SIGCOMM Computer Communication Review (CCR), v.37, n.3, 2007. • Transport layer • RFC 2960: Stream Control Transmission ProtocolRFC 4347: Datagram Transport Layer Security RFC 4340: Datagram Congestion Control Protocol (DCCP) Designing DCCP: Congestion Control Without Reliability (PDF), by Eddie Kohler, Mark Handley, and Sally Floyd. Proc. ACM SIGCOMM 2006. • NATs • RFC 3489 STUN - Simple Traversal of User Datagram Protocol (UDP) Through Network Address Translators (NATs). IETF Journal article on ICEPeer-to-peer Communication Across Network Address Translators  • AAA • RFC 2865: Remote Authentication Dial In User Service (RADIUS)RFC 3588: Diameter Base Protocol • QoS • RFC 3272: Overview and Principles of Internet Traffic EngineeringRFC 3031: Multiprotocol Label Switching Architecture • HIP • RFC 4423: Host Identity Protocol (HIP) Architecture  • Services • Amazon's Dynamo. SOSP 2007.

10. Assignment • Mandatory assignment: packet capture using WireShark • Goal: to get hands on experience with protocols • Write 2 page report on WireShark protocol analyzer and use it to analyze some traffic (TCP, SCTP, TLS, DTLS, IPsec, HIP, some other) • Can be done as pairwork or alone • http://www.wireshark.org/

11. Contact Points • Send email • sasu.tarkoma@tkk.fi • Follow course web-page • Results and updates will be posted to the Web • Reception • After the lectures • Otherwise send email to arrange a meeting • Exam reception will be scheduled after results

12. Summary of Course • As discussed the course focuses on several important features of current networking systems • Mobility, QoS, Security, Privacy • We observe that these features were not important for the original Internet architecture • They are important now • Mobility, QoS, Security are coming with IPv6 • IPv6 deployment does not look promising • Hence, many proposals to solve issues in the current Internet • Also many solutions to solve expected problems in the Future Internet

13. Layered Architecture • Internet has a layered architecture • Four layers in TCP/IP • Application (L7) • Transport (L4) • Network (L3) • Link layer / physical (L2-L1) • We will talk a lot about layering • Benefits, limitations, possibilities (cross-layer) • It is not always clear what is a good layering • A lot of interesting networking developments are happening on application layer

14. Convergence and Divergence Applications and Services Divergence TCP/IP Convergence Wireless / wireline protocols

15. The Internet has Changed • A lot of the assumptions of the early Internet has changed • Trusted end-points • Stationary, publicly addressable addresses • End-to-End • We will have a look at these in the light of recent developments • End-to-end broken by NATs and firewalls

16. Network has Value • A network is about delivering data between endpoints • Data delivery creates value • Data is the basis for decision making • We have requirements to the network • Timeliness • Scalability • Security • ...

17. Cisco’s Traffic Forecast

18. Trends in Networking

19. Current State • Internet is growing fast (40%+ annual growth) • Much of the growth comes from P2P and video delivery • There are circa 1 billion Internet users and 3.3 billion mobile phone users • Mobile Internet is anticipated to grow rapidly • Many problems with applications and services • It is very difficult to change the Internet backbone and large access networks • Overlay solutions • Middleboxes • A lot of discussion on Internet architecture • Clean-slate vs. incremental

20. Looking at the Layers • Link Layer / Physical • Network • We will look at mobility, security, and QoS on L3 • Mobile IP, network mobility, HIP, NAT Traversal • Transport • Basic properties of transport layer protocols • TCP variants, DCCP, TLS, dTLS • Mobility and security on L4 • Application • Security, identity management • Goal: have an understanding of the solutions and tradeoffs on each layer and discussion on the role of layering

21. HTTPS, S/MIME, PGP,WS-Security, Radius, Diameter, SAML 2.0 ... Application Application Transport Transport TLS, SSH, ... HIP Network Network IPsec Link PAP, CHAP, EAP, WEP, ... Link Physical Physical

22. Role of Standards • On this course, we will talk a lot about standards • IETF is the main standards body for Internet technologies • Instruments: RFCs, Internet drafts • Working groups • IRTF • Other relevant standards bodies • W3C, OMA, 3GPP, OMG

23. Transport Issues • Network layer (IP) provides basic unreliable packet delivery between end-points • Transport layer needs to provide reliability, congestion control, flow control, etc. for applications • TCP variants • SCTP • DCCP • TLS • DTLS

24. Mobility • What happens when network endpoints start to move? • What happens when networks move? • Problem for on-going conversations • X no longer associated with address • Solution: X informs new address • Problem for future conversations • Where is X? what is the address? • Solution: X makes contact address available • In practice not so easy. Security is needed!

25. Classifying Mobility Protocols Mobility Global Macro Micro MIP (1996) Hierarchical MIP (1996) Cellular IP (1998) Hawaii (1999) Dynamic Mobility Agent (2000) Time (evolutionary path) MIPv6 (2001) TMIP (2001) HMIPv6 (2001) Intra-subnet Inter-domain Intra-domain

26. NAT Traversal • As mentioned, end-to-end is broken • Firewalls block and drop traffic • NATs do address and port translation • Hide subnetwork and private IPs • How to work with NATs • Tricky: two NATs between communications • NAT and NAPT • One part is to detect NATs • Another is to get ports open • IETF efforts • STUN • ICE • TURN • NSIS

27. QoS • By default, there is no QoS support on the Internet • IP is unreliable, packet types are handled differently (TCP/UDP/ICMP) • No guarantees on TCP flow priority (OS and NW stack issue) • IETF work • DiffServ, IntServ, NSIS

28. Security Features • IPSec provides basic security (tunnel,transport) with IKE • Solution for autentication, authorization, accounting is needed (AAA) • Radius, Diameter • Case: WLAN access network

29. HIP • HIP is a proposal to unify mobility, multi-homing, and security features that are needed by applications • Identity-based addressing realizing locator-identity split • Change in the networking stack that is not very visible to applications (no IP addresses though!) • HIP architecture, HIP implementation for Linux

30. NetFPGA • The NetFPGA is a low-cost platform for teaching networking hardware and router design, and a tool for networking researchers. • The NetFPGA offloads processing from a host processor. • The host's CPU has access to main memory and can DMA to read and write registers and memories on the NetFPGA. • A hardware-accelerated datapath. • Four Gigabit ports and multiple banks of local memory installed on the card. • Uses Verilog and a cross compilation environment.

31. http://netfpga.org/static/guide_beta_1_1.html

32. Software Hardware Basic Architectural Componentsof an IP Router Management & CLI Routing Protocols Control Plane Routing Table Datapath per-packet processing Forwarding Table Switching Reference: http://yuba.stanford.edu/cs344_public/

33. Bloom Filters • Network applications of Bloom filters y x z 0 1 0 1 1 1 0 0 0 0 0 1 0 1 0 1 0 0

34. Privacy and Identity Management • Privacy and trust matters a lot • Single sign-on • Liberty, OpenID, OAuth, GAA, .. • Services on the Web • How to achieve scalability • Case: Amazon Dynamo • Recent developments

35. Questions and Discussion