UCDavis, ecs251 Spring 2007 05/18/2007Davis Social Links1 Davis Social Links A Socially Structured P2P System S. Felix Wu University of California, Davis

05/18/2007 Davis Social Links 1

UCDavis, ecs251Spring 2007

Davis Social LinksA Socially Structured P2P System

S. Felix WuUniversity of California, Davis

[email protected]://www.cs.ucdavis.edu/~wu/


UCDavis, ecs251Spring 2007 P2P

• Unstructured P2P– Napster, Bittorrent

• Structured P2P– DHT/Chord


UCDavis, ecs251Spring 2007 Unstructured P2P


UCDavis, ecs251Spring 2007 Unstructured P2P

Where is this piece of music?What is the location of this content?What is the current IP address of this skype user?


UCDavis, ecs251Spring 2007 Structured P2P


UCDavis, ecs251Spring 2007 DHT-based BT Tracker

Index key(Content-Dependent)

The owner of the identifier matching this hash entry will be the tracker for the corresponding index key!

Sharing/DownloadingFreeBSD 5.4 CD images

PUT & GET


UCDavis, ecs251Spring 2007 DHT-based P2P

Index keyRouting from a key to an identifier

PUT & GET


UCDavis, ecs251Spring 2007 DHT vs. DSL

• DHT– [Contents, Keys, Identifiers]– Conceptually, we have a global hash table!

• DSL– [Contents, Keys, Relative Identifiers]– Social/trust relationships along the route

path


UCDavis, ecs251Spring 2007 DSL Peers


UCDavis, ecs251Spring 2007 A Social Link

representing a trust relationship in the application layer.

Trust Attribute


UCDavis, ecs251Spring 2007 Requirement for a Social Link

They know how to communicate with each other (such as IP or email addresses) in any layer!

Trust Attribute


UCDavis, ecs251Spring 2007 Social Keywords

Soccer, BGP, Davis, California, Intrusion Detection,…


UCDavis, ecs251Spring 2007 Social Keywords

Soccer, BGP, Davis, California, Intrusion Detection,…

Social keywords represents your interests and the semantic/social interpretation of you.

Ownership


UCDavis, ecs251Spring 2007 Identifier and Key

• Under DSL, each peer has its own decision or policy regarding what “social keywords” to announce, and it can change the announcement itself any time.

• There is NO global identifier.• Relative Peering relationship only.


UCDavis, ecs251Spring 2007 DHT

• The binding among Content, Key, Identifier is “relatively static”.

• Once the key of the content is known, the route path to the identifier/key owner is determined, assuming the DHT ring is stable.– What does this imply?


UCDavis, ecs251Spring 2007 Multiple Social Links

BGP, Davis, California, Intrusion Detection,…

Soccer, Wine, Bike, Davis, California,…


UCDavis, ecs251Spring 2007Social Keywords can be Anything

Lord_of_the_Ring, Spiderman3, Royal Casino, Troy, …

[email protected], [email protected],…


UCDavis, ecs251Spring 2007 Propagation


UCDavis, ecs251Spring 2007 Aggregation

Ownership

Ownership

Similar to Scope-Limited Flooding in Gnutella/Freenet, but more scalable with aggregation.


UCDavis, ecs251Spring 2007 How to Aggregate?

• Local rules or dictionaries• {s1, s2,… , sn} --- “S”


UCDavis, ecs251Spring 2007 How to find “content X”?

Owner of X Other Peers

Remember that under DSL there is no such thing called “global identifier”.


UCDavis, ecs251Spring 2007Use the right “keywords for X”!


Query


UCDavis, ecs251Spring 2007 Example

PotentialTargets

PotentialPeers

“Davis,CA”

“Sacramento,CA”

Northern CaliforniaGreater Sacramento Area

Which keywords to use?



PotentialTargets

PotentialPeers

“Davis,CA”

“Sacramento,CA”


“North California”“Davis, CA”


UCDavis, ecs251Spring 2007 No Unique Identifier!!!

• Two peers might announced exactly the same set of keywords!



PotentialTargets

PotentialPeers

“Davis,CA”

“Davis,CA”


Who will receive the query??

Query




• Both of them will receive the query, and this might not be a problem.






• Both of them will receive the query, and this might not be a problem.

• Usually, end2end applications can tell which one (or ones) is really wanted.


UCDavis, ecs251Spring 2007 DSL in a Social Network


QueryAppTest


UCDavis, ecs251Spring 2007 Trackerless BitTorrent


QueryAppTest


UCDavis, ecs251Spring 2007 Tracker Volunteer

Volunteer Other Peers

QueryAppTest

Content/KeyTracker




UCDavis, ecs251Spring 2007 Tracker Volunteers

Volunteers Other Peers

QueryAppTest

Content/KeyTracker


UCDavis, ecs251Spring 2007 DSL-Torrent

• How to seed your torrent?– Use DSL to search for all the volunteers– You can screen out “unqualified” trackers

by not contacting them. (owner controllability)

• How to contact/select the tracker(s)?– Use the keywords, of course– But, use the right aggregation keywords to

reach the trackers closer to the “UCDavis” social circle!




UCDavis, ecs251Spring 2007 Monitoring

• Seed• Tracker• With Trackerless, the inspector might

become the tracker itself to record all the IP addresses of the peers– Traceability vs. Privacy

• How about DSL-Torrent?




UCDavis, ecs251Spring 2007 DSL vs. Google


UCDavis, ecs251Spring 2007 “Google”

• It’s about the “content”– Data-centric networking.

• Input to the Engine– A set of key words characterizing the target

document.

• Output– A set of documents/links matching the

keywords


UCDavis, ecs251Spring 2007 “DSL”

• It’s also about the “content”– Application will decide the mechanism to

further the communication.

• Input to the Decentralized Engine– A set of key words characterizing the target

document (plus the aggregation keywords).

• Output– A set of DSL entities with the DSP (Davis

Social Path pointer) matching the keywords


UCDavis, ecs251Spring 2007 DSL Search Engine

DSL Social World

Receiver orContent

Sender orReader

We are not just connecting the IP addresses!We are connecting all the contents that can be interpreted!


UCDavis, ecs251Spring 2007 Google vs. DSL

• Google is essentially a “routing” framework between the contents and their potential consumers.

• Google decides how to extract the “key words” from your (the owner) web page or document.


UCDavis, ecs251Spring 2007 Google vs. DSL

• Google is essentially a “routing” framework between the contents and their potential consumers.

• Google decides how to extract the “key words” from your (the owner) web page or document.

• A DSL “owner/receiver to be” has the complete control over that. A balance between:– How I would like others to know about me?

• And, I might want different folks to know me in different ways!

– How I can differentiate myself from other Felix Wu?


UCDavis, ecs251Spring 2007 DSL (Davis Social Links)

Principle:– Communication should reflect the

(social/trust) relationship between the sender and the receiver, and the receiver should have ways to control that.

Design:– Route discovery based on social keywords

and their potential aggregation– Separation of identity and routability– Penalty and Reputation framework

A B

A BF

FF


UCDavis, ecs251Spring 2007Separation of Routing & Identity

• Under DSL, we do not have any fix format identity (defined and interpreted by applications).


UCDavis, ecs251Spring 2007 Internet and IP address

• Basic datagram service between one IP address and another

• Routing: exchanging the information regarding the address space and how to reach them.

• Applications built on top of the services– Skype, Google, Bittorrent, Youtube, IM,…


UCDavis, ecs251Spring 2007Separation of Routing & Identity

• Under DSL, we do not have any fix format identity (defined and interpreted by applications).

• In route discovery, the “sender to be” within DSL has no idea whether that is the “right” receiver!– Try “Felix Wu” on Google…– And, some applications don’t even care

about that.– The “receiver to be” will need to answer an

application level challenge within the route discovery process.


UCDavis, ecs251Spring 2007 Communication

• Applications: email, skype, bittorrent, warcraft, youtube, www.united.com, im– Why do I need IP address as a user?– Why do I need DNS lookup as a user?– Why do we need global identity?

• Global connectivity without global identity!


UCDavis, ecs251Spring 2007 An Identity under DSL

• “Key words” plus one or more DSL paths– Why will this be sufficient for

communication?– Especially, when even the DSL information

itself is decentralized? (I.e., in general, no one single DSL router knows the complete DSP.)


UCDavis, ecs251Spring 2007Are you two talking to the same Felix

Wu?

• We can have so many simple tests if it is true.


UCDavis, ecs251Spring 2007 Keyword: [email protected]

• I sent you an email earlier containing two “secure random numbers”. Here is the first one, and what is the other one?


UCDavis, ecs251Spring 2007 A Social Link


UCDavis, ecs251Spring 2007 An extra plane

• Data, Control, Management planes– Internet Reference model

• Trust and Social Plane!

• Traceability– Tracing routers is one thing (probably not

very interesting)– Tracing the social relationship is the key to

almost everything!



DSL Route Discovery& Trust Management

DSL Forwarding Plane



Global Communication Infrastructure

• Information assurance about the infrastructure itself

• Supporting securer & more effective communications– Internet infrastructure is somewhat

“neutral”.– If we have a common software vulnerability,

the Internet guarantees that a robust botnet can be rapidly developed at “network speed.”


UCDavis, ecs251Spring 2007Problem? or “Internet is doing

exactly what it supposed to do!”

• spam/spit/spim, worm, spyware, DDoS, virus, phishing, cyberbully…

• Proposition #1: can the applications (plus firewall/IPS/NAT, maybe PKI) be able to win the battle by themselves?

• Proposition #2: can the network infrastructure help in a fundamental way?


UCDavis, ecs251Spring 2007Issues about Internet Security

• Mixtures of Good and Bad activities• Privacy is not really preserved while we

can not trace the attack sources• The trust is very ad hoc -- e.g., anybody

can claim to be N years old in blog or the most honest seller on eBay

• Detection is arm-racing, while prevention is not really clear what to prevent


UCDavis, ecs251Spring 2007Problem? or “Internet is doing

exactly what it supposed to do!”

• spam/spit/spim, worm, spyware, DDoS, virus, phishing, cyberbully…

• Proposition #1: can the applications (plus firewall/IPS/NAT, maybe PKI) be able to win the battle by themselves?

• Proposition #2: can the network infrastructure help in a fundamental way?– I don’t know but I will give it a try…


UCDavis, ecs251Spring 2007 Contact me!

FROM:MR.CHEUNG PUIHang Seng Bank LtdSai Wan Ho Branch171 Shaukiwan RoadHong Kong.

Please contact me on my personal box [[email protected]]

Let me start by introducing myself. I am Mr. Cheung Pui,director of operations of the Hang Seng Bank Ltd,Sai Wan Ho Branch. I have a obscured business suggestion for you.

Before the U.S and Iraqi war our client Major Fadi Basem who was with the Iraqi forces and also business man made a numbered fixed deposit for 18 calendarmonths, with a value of Twenty Four millions Five Hundred Thousand United State Dollars only in my branch. Upon maturity several notice was sent to him,…



The same message content

• “M” from Cheung Pui

• “M” from Cheung Pui via GGCS mailing list

• “M” from Cheung Pui via Felix Wu



Social Link Identification

• “M” from Cheung Pui Probably a spam• “M” from Cheung Pui via GGCS mailing

list Probably not interesting• “M” from Cheung Pui via Felix Wu Better be more serious… (at least I

hope)


UCDavis, ecs251Spring 2007 Social Links

• We have been utilizing the social infrastructure to enhance our communication for a long time!

• But, can we bring it to the cyber space?– So our trust can be propagated and

managed in network speed!



Route Discovery Messages

Soccer, BGP, Davis, California, Intrusion Detection, Liechtenstein

AND/OR expression

Soccer, BGP, Davis, California, Intrusion Detection, Liechtenstein+ a few extra

{ a bag of expected words}

Accepted or not??

Receiver



Route Discovery & DSL Table

001 002

PotentialReceivers

PotentialSenders

incoming outgoingDSL ID

Davis California Japan001

Japan Northern California002

003

Davis CANorthern California


UCDavis, ecs251Spring 2007 Limited Resources

.

.

.

.


UCDavis, ecs251Spring 2007 M

.

.

.

.

Keywords and aggregated keywords

“content addressable emails”



Function F(incoming) = outgoing

001 002

PotentialReceivers

PotentialSenders

incoming outgoingDSL ID

Davis California Japan001

Japan Northern California002

003

Davis CANorthern California

Policy drivenMaybe itself a service



Forwarding: Source Routing

Sender:Data packet SR003, 001



Forwarding: Source Routing

003

001

Sender:Data packet SR003, 001



Traceability

• Any one individually in the Internet won’t know much about who is talking to what.

• But, if necessary, we can trace back hop by hop using local DSL ID.


UCDavis, ecs251Spring 2007 Social Connection

• In route discovery, the receiver might want to know “how are we socially connected?”

• It is controlled by the sender and the intermediate DSL routers regarding how much information need to expose?– Part of the “application test”– If we are going to expose any information,

we need to know why (I.e., the application)– Maybe, we need intermediate DSL router

tests as well!


UCDavis, ecs251Spring 2007 Traceability

• Support infrastructure, social routers– Forensics available per data packet

• If one person launches a command to a large number of bots to DDoS/spam some victim, we will be able to identify how this person is “socially connected” to the communication infrastructure.– And, still we will maintain reasonable/strong

user privacy.



DSL Route Discovery& Trust Management

DSL Forwarding Plane


UCDavis, ecs251Spring 2007Parallel/Overlay Communication


UCDavis, ecs251Spring 2007 Parallel Information

• Information among applications• Meta-information regarding the

information!– Social path information

information

Meta Information


UCDavis, ecs251Spring 2007 Filtering in “Layer-3”

• IP header and Transport header• Packet payload analysis


UCDavis, ecs251Spring 2007 Filtering in DSL

• “Social Path”

information

Meta Information


UCDavis, ecs251Spring 2007 Penalization

• If Alice had forwarded lots of junk mails to Bob, then Bob will lower the priority of the social link between them.

• Alice will be informed about the downgrade.

• Alice needs to investigate “which messages” (from which incoming DSLs) were causing the downgrade.


UCDavis, ecs251Spring 2007 Asking a Question

• Get on the bus, Information!

information

DSL query


UCDavis, ecs251Spring 2007 Query

The Social Plane

Application

DSL Virtualization

information information

DSL query

Application

DSL Virtualization

DSL query


UCDavis, ecs251Spring 2007 On/Off the Bus

• A query– “Is this an attack/virus/worm?”

• A comment– “I am pretty sure that this is an virus, and

you need to harden your environment before you let it off the bus.”

• A trace– “I want to know who will receive this piece

of information indirectly.”


UCDavis, ecs251Spring 2007 P2P Incentives

• Trade-off between privacy and availability– If you don’t help in revealing the identities

of some communication sessions, you might be downgraded.

– If you are too easy to give away some identity related information, you might be downgraded as well.


UCDavis, ecs251Spring 2007 Revisit Connectivity

• IPv4/v6 or even email address– You have one IP address and you will be

able to connect to every other IP address (if you know who they are).

– Problem of binding between application-layer identity and network-layer identity

– Spam/DDoS


UCDavis, ecs251Spring 2007 Definition for DSL Connectivity

• Given a Stable/Converged Aggregate Table– One DSL node will be able to discover at

least one DSL route path toward every other node as long as it knows the origin keywords for the destinations.

– Connectivity means that we will be able to reach all DSL nodes advertising the same bag of origin keywords.

– Aggregation knowledge -- through the asynchronous converging process (toward a system fixed point).


UCDavis, ecs251Spring 2007 Fairness in Communication

• Sender Fairness– If you wish to communicate with another

DSL entity, as long as you know the origin keywords, you should have “equal” chance to find “a” path to reach the destination.

– Social differentiation is still there (for the knowledge of origin keywords), but there should be nobody in the middle can block your communication!


UCDavis, ecs251Spring 2007 DSL Connectivity

• It is possible that some DSL entities converge into different ways of aggregation for the same set of origin or aggregate keywords.

• But, the connectivity definition is still hold.– As long as the sender knows how to get

through it!


UCDavis, ecs251Spring 2007 Comparison

• IP/email:– Convergence to an absolute consistent state– IP/email addresses are all you need, but the

controllability is biased toward the sender

• DSL:– Convergence to a relative consistent state– No global identity. Every DSL entity defines

its own identity based on origin keywords.– Controllability is more balanced with other

application challenges.



Message Prioritization

Application IDSControl Mechanisms:

Link RanksReputation

Other Trust-Management Metrics


UCDavis, ecs251Spring 2007 DSL is an old idea!

We, as human, have been using similar communication principles.

Maybe it is a good opportunity to re-think about communication and trust.

Application-level security will play a major role, but will the infrastructure be sufficient to support the end2end security efficiently?

A B

A BF

FF

Documents

UCDavis, ecs251 Spring 2007 05/18/2007Davis Social Links1 Davis Social Links A Socially Structured P2P System S. Felix Wu University of California, Davis