Lecture 3Lecture 3- Why the Internet only just works- Why the Internet only just works- What can we do about it?- What can we do about it?

D.Sc. Arto Karila

Helsinki Institute for Information Technology (HIIT)

arto.karila@hiit.fi

T-110.6120 – Special Course in Future Internet Technologies

M.Sc. Mark Ain

Helsinki Institute for Information Technology (HIIT)

mark.ain@hiit.fi

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*** NOTICE *** The following readings are now

mandatory: DONA I3 SEATTLE

The following lectures are cancelled: Tue 25.09 Mon 01.10 Mon 08.10

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Computer networking Developed for mainframes

(on the left ENIAC and on the right IBM S/360)

Sharing devices: computers, mass memory, printers etc. with addresses

Point-to-point trafficbetween two devicesor network interfaces

The old paradigm stilllives even though the world around has completely changed

Picture source: IDG News Service

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Contents

What’s wrong with the Internet today What can we do about it?

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What’s wrong with the Internet today?

1) Sender empowerment2) Endpoint-centrism3) Infrastructure trustworthiness4) Application deployment5) Congestion control6) Inter-domain routing7) Multi-homing8) Address space9) Identifier-locator unification

Mobility10)QoS11)Multicast and caching

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Sender empowerment In the 1960s…

Computers were large and very resource-limited by modern standards

Data was stored, input, and output by physical means e.g. punch cards; you took your data with you

ARPANet was organized to address the need for efficient resource-sharing amongst computers of the time (NOT content sharing!)

The send-receive communication paradigm was simple, arguably obvious, and well-suited for the purposes of the time.

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Sender empowerment

Today… Computers are small, resources are abundant, content is at

the forefront of (user) attention Send-receive may not be optimal

Result: SPAM, DoS, concealment (firewalls, middleboxes etc.) etc.

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Quick look: SPAM (2009)

Estimates…Upwards of $130 billion USD in global losses (2009 USD, average EUR-USD exchange rate, unadjusted for inflation 2012)~62 trillion messages per yearServer-side filtering could hypothetically save ~135TWh of energy per year = ~17 million metric tons of CO2 emissions

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Endpoint-centrism

The future: content-centrism Get “x” simply by asking for “x”…

the network finds “x” and delivers it innately based on “x”

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Endpoint-centrism

The reality: endpoint-centrism Get “x” by asking WHERE is “x”,

receiving response “y”, then fetching “x” from ”y”.

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Infrastructure trustworthiness

Trust is irrational – however, there is a mathematical foundation for it

The Internet was developed for a community where everybody was assumed trustworthy

Now that the Internet is used by everybody, it is vital to enable communication between parties that don’t trust each other

We need mechanisms by which people and companies can build and evaluate trust

Good reputation can be made an asset worth protecting

Combining privacy and reputation is challenging17.09.2012 11

Infrastructure trustworthiness

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Application deployment

“There is a vicious circle – application developers will not use a new protocol (even if it is technically superior) if it will not work end-to-end; OS vendors will not implement a new protocol if application developers do not express a need for it; NAT and firewall vendors will not add support if the protocol is not in common operating systems; the new protocol will not work end-to-end because of lack of support in NATs and firewalls.”

- M. Handley

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Application deployment

E2E principle should in theory make it easy to deploy applications over many hosts without worrying about interactional problems across network

Unfortunately, this is not the case, as evolutionary developments and patchwork solutions (e.g. NAT) have broken E2E on many levels

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Application deployment

Internet stagnancy feedback loop

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Internet stagnancy feedback loop

A “chicken and the egg” problem Discussion: what happens first?

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Congestion control

It was implemented at the transport layer (TCP, mid-late 1980’s) because it was too late in the Internet’s development to change the core protocol stack

TCP congestion control is largely successful, but incremental, and plagued by insufficiencies (next slide)

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Congestion control

TCP problems…1. Only reacts to congestion, does not proactively

prevent it; insufficient convergence times2. Changing application and per-flow

requirements variety of security, performance, and compatibility problems

3. Poor performance over links with high B*D product; too slow to converge, too aggressive backoff

4. Not designed for wireless environments; TCP reacts to packet loss as though it were congestion.

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Inter-domain routing

The current inter-operator routing protocol BGP-4 does not fulfill modern requirements but there is no successor to it in sight

Tier-1 operators (AT&T, MCI, Sprint, C&W etc.) are a group of about a dozen global operators with mutual peering agreements

In Practice they form a cartel, which wants to cement the market and is not advocating development

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Inter-domain routing

BGP policy routing mechanisms were a reaction to an abundance of users and the potential for commercial competition

BGP operation centered on… AS’s are separate and equal Route-path information is commercial sensitive

BGP attempts to avoid unecessarily releasing route-path information subject to misconfiguration, vulnerability, slow convergence etc.

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Multi-homing

Reliability, transparent-failover, and load-sharing often necessitate multi-homed connections

Problem: the mere presence of multiple IP prefix announcements on a wide-scale removes the benefits of hierarchical IP aggregation

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Address space

IPv4 once though inexhaustible Despite evolutionary patchwork (NAT,

DHCP, improved allocation policies, reclamation projects etc.), IPv4 is exhausted

IPv6???

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IPv6 IPv6 was defined in 1995 and expected to spread fast

It is still hardly used in Western countries

The main improvement of IPv6 is moving from 32-bit to 128-bit addresses

IPv6 was defined at a time when nobody could foresee all of the uses and needs of the Internet that we have now

The transition to IPv6 will be a long one and it won’t solve most of the problems

Planned Actual

?

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Identifier-locator unification

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Identifier-locator unification Mobility raises 5 fundamental problems…

1) Locating the mobile host and/or service2) Preserving communication3) Disconnecting gracefully4) Hibernating efficiently5) Reconnecting quickly

The root cause of problems 1 and 2 is IP semantic overload i.e. identifier-locator unification; the last 3 are largely unaddressed!

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QoS

DiffServ and IntServ are NOT built-in to the network or protocol independent

DiffServ does not provide end-to-end guarantees

IntServ requires cooperation amongst providers and network state

How do we provide protocol-independent QoS, built-in to the architecture, preserving E2E, without necessarily requiring network state etc?

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Multicast and Caching

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In summary…

No major changes have been made to the core protocols of the Internet since 1993 (CIDR)

The core protocols of the Internet are ossified while the needs have developed significantly

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Contents

What’s wrong with the Internet today What can we do about it?

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Evolution vs. revolution The Internet has developed from the 1970’s in

an evolutionary way, with no big changes As concluded before, this has led into a

situation where it is very hard to make changes to the core protocols

Among researchers and developers of the Internet, there is a growing opinion that something fundamental has to be done at some point

It the Internet was to be designed from the scratch, it would probably become very different from what it has evolved to

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Evolution vs. revolution

Various clean-slate solutions are current research topics and some of them may lead into a new Internet

It is possible that all the protocol layers, including the Internet Protocol, will change

However, it looks like any new solution would have to be able to operate as overlay above the existing IP infrastructure, in order to have a change to proliferate

The publish/subscribe paradigm (pub/sub) is one of the most promising new paradigms (for more information see www.psirp.org and www.fp7-pursuit.eu

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Microeconomics Over the past ten years, microeconomics have

grown in importance

We need economic mechanisms that encourage people to do good for the community

The Internet was developed with public funds for research and education without any commercial considerations

If we want to inject resources into the network, it must be possible for the party paying for them to also receive (some of) the revenues

We need to create ways for companies and people to improve their own economies by doing things beneficial for the community

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For tomorrow…

READ Van Jacobson, Diana K. Smetters, James D. Thornton,

Michael F. Plass, Nicholas H. Briggs, and Rebecca L. Braynard. 2009. Networking named content. In Proceedings of the 5th international conference on Emerging networking experiments and technologies (CoNEXT '09). ACM, New York, NY, USA, 1-12. DOI=10.1145/1658939.1658941 http://doi.acm.org/10.1145/1658939.1658941

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Thank you for your attention!Thank you for your attention!Questions? Comments?Questions? Comments?

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