T-110.5110 Computer Networks II: Advanced Features

Introduction

13.9.2010 Matti Siekkinen

September 20, 10

Contents

! Motivation and substance "  Why do we teach what we teach? "  What are the focus areas and how they relate to the

“big picture”? ! Practical information

"  Course Outline "  Passing the course "  Lectures and schedule "  Reading material

September 20, 10

What is the Internet Architecture?

! Internet has a layered architecture ! Four layers in TCP/IP

"  Application (L7) "  Transport (L4) "  Network (L3) "  Link layer / physical (L2-L1)

! Layering has a big impact "  Benefits, limitations, possibilities (cross-layer) "  It is not always clear what is a good layering

September 20, 10

Hourglass model

email WWW phone..."

SMTP HTTP RTP..."

TCP UDP…"

IP"

ethernet PPP…"

CSMA async sonet..."

copper fiber radio..."

Deering, 2001

! Why an internet layer? "  make a bigger network "  global addressing "  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

September 20, 10

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 "  …

September 20, 10

Textbook Internet vs. Real Internet

H. Schulzrinne, 2009

September 20, 10

Textbook Internet vs. Real Internet

H. Schulzrinne, 2009 September 20, 10

More about current state and trends

! Internet is growing fast (40%+ annual growth) "  Much of the growth comes from P2P and video

delivery ! 1 billion Internet users and 3.3 billion mobile

phone users "  -> Mobile Internet is anticipated to grow rapidly

! Very difficult to change the Internet backbone and large access networks "  We are stuck with IP and BGP "  Overlay solutions and middleboxes

! A lot of discussion on Internet architecture "  Clean-slate vs. incremental

September 20, 10

Some of the Internet’s Challenges ! IPv4 address depletion

"  We run out of them, IPv6 to rescue… ! NAT and middle boxes

"  Break the transparency/end2end, complicates protocol/service development

! Growth (scalability) "  Routing infrastructure "  Efficient content distribution "  Minimizing cost of operation

! Quality of service "  Availability/reliability

September 20, 10

Some of the Internet’s Challenges (cont.)

! Security "  No need to explain…

! Mobility "  What happens when network endpoints start to move? "  What happens when networks move?

! Challenged environments "  Sensor networks "  Lack of or damaged infrastructure "  Interplanetary Internet # "  E.g., standard TCP/IP does not work well

September 20, 10

What do we teach?

CHALLENGES

IPv4 address depletion

NAT and middle boxes

Growth (scalability)

Quality of service

Security

Mobility

Challenged environments

TEACHING TOPICS

Delay Tolerant Networks

Advanced transport protocols

Bloom Filter-based networking

Host Identity Protocol

Quality of Service

Network diagnostics

Green communications

Data centers

Sensor networks

September 20, 10

Delay Tolerant Networks (DTN)

! TCP/IP protocol stack assumes that network is connected

! Problems occur if "  Network is partitioned into several subnetworks "  Very long delays (inter-planetary) are involved "  So called challenged networks

! DTN encompasses a large set of solutions for these situations

September 20, 10

Advanced Transport Protocols !  Network layer (IP) provides basic unreliable packet

delivery between end-points !  Transport layer needs to provide reliability, congestion

control, flow control for applications !  Basic TCP limited with

"  Fat pipes "  Wireless networks

!  TCP variants "  There are really many…

!  SCTP "  Transmit messages instead of segments "  Support for multiple streams

!  DCCP "  UDP+congestion control

September 20, 10

Bloom Filter-based networking

! Clean slate-type of architecture research ! Use in-packet Bloom filters for source route-style

forwarding "  No IP addresses "  Encode sequence of link IDs into in-packet bloom filter "  Provides means to implement efficient multicasting

! Applications "  Content based publish/subcribe networking "  …

September 20, 10

Host Identity Protocol (HIP)

! Mobility "  On-going conversations

o  X no longer associated with address "  Future conversations

o  Where is X? what is the address? ! HIP: Solution for locator/identifier split

"  Locator: how to find X "  Identifier: Who is X? "  IP serves as both "  -> obvious problem with mobility

! Also provides "  Multihoming "  Security

! Change (more or less) invisible to applications

September 20, 10

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) ! Plenty of IETF work

"  DiffServ, IntServ, NSIS ! Service availability and reliability

"  Service value depends heavily on this ! Tightly linked to next topic…

September 20, 10

Network diagnostics

! How is my network/services doing? "  Surprisingly difficult question to answer

! What is/went wrong? "  Discovering root causes is even more difficult

! Important for "  Any enterprise network

o  Ability to run basic services "  ISPs

o  Want happy clients ! Traffic measurements is part of this activity

September 20, 10

Green communications

! Energy consumed by ICT "  This is a lot when measured globally (12%)

! So what? "  $!

! Also: mobile users point of view "  Battery life time is an issue "  This is more a question of QoS than “greenness”

September 20, 10

Data centers

! Large data centers are essential for many service providers "  Web search, email, content distribution, … "  Google runs (probably) over 1 million servers by now

! Provide specific networking challenges "  Can have very small latency and very high throughput

! How to optimize costs? "  Infrastructure costs money (buy and maintain)

! Efficient, robust, and flexible data center architectures needed "  Deal with failures "  Dynamic resource allocation (power efficient)

o  Virtualization

September 20, 10

Sensor networks

! Sensors have strict battery constraints ! -> special emphasis on solutions for

"  Routing "  Data aggregation "  Etc.

! Many applications "  Structure monitoring "  Smart home "  Many industrial applications

September 20, 10

What we don’t teach !  Nevertheless important topics! !  IPv4->IPv6 transition

"  IPv6 rescues us from address depletion "  Need solutions for interoperability

!  Secure and scalable routing "  Secure routing protocols "  How to design and build fast routers

!  DNS scalability and robustness !  Many other “Future Internet” architecture initiatives !  Privacy and security in general

"  See other lab courses: T-110.x2xx !  Wireless access/infrastructure networks

"  Wireless mesh networks, WLAN, Cellular networks (LTE) "  See T-110.5120

September 20, 10

Course Outline ! 4 credit course ! Topics covered

"  Novel and emerging architectures, paradigms, and protocols

o  Bloom filter-based networking, HIP, transport protocols, data centers

"  Operational networks and protocols o  Quality of service (QoS), diagnostics, energy efficiency

"  Different types of networks o  DTN, sensor networks

! Course consists of the lectures and a final exam ! Reading material provided beforehand

"  Read it before lecture "  Discuss during the lectures

! Everything will be in English

September 20, 10

Course Goals

! Understand advanced networking techniques ! Learn state of the art ! Get a glimpse to near-future technologies and long

haul development ! Most topics closely related to our research

interests and activities

September 20, 10

Time and Place

! Time and place: Mondays at 14:15 – 16:00 in T2. ! Lecturers:

"  Matti Siekkinen "  Guests:

o  DTN: Prof. Thomas Plagemann o  Bloom filter -based networking: Petri Jokela (Ericsson

research) o  HIP: Miika Komu o  Green communications: Yu Xiao o  Sensor networks: Nie Pin

September 20, 10

Passing the Course

! Participation to lectures ! Final exam

"  16.12.2010 16:30-19:30 in T1 "  Based on all course material:

o  Slides o  Indicated reading material

! Required preliminary knowledge "  T-110.300 Telecommunication Architectures "  T-110.350 Computer Networks

September 20, 10

Reading material

! Two articles/documents (RFC) per lecture "  Will be posted in Noppa (Additional reading section)

before each lecture ! Read preferably before lecture

"  Helps orientate to lecture "  Initiate discussion during lectures

! Will be part of the exam

September 20, 10

Contact Points

! Send email "  matti.siekkinen@tkk.fi

! Follow course in Noppa "  Results and updates will be posted via Noppa news

! Reception "  Come and talk to me after lectures "  Otherwise send email to arrange a meeting "  Exam reception will be scheduled after results

Questions?