Thursday, January 12, 2017

Learning Notes on: "Rationality and Self-Interest in Peer to Peer Networks"

Rationality and Self-Interest in Peer to Peer Networks
By: Jeffrey Shneidman and David C. Parkes

Paper Abstract:

Much of the existing work in peer to peer networking assumes that users will follow prescribed protocols without deviation. This assumption ignores the user’s ability to modify the behavior of an algorithm for self-interested reasons.
We advocate a different model in which peer to peer users are expected to be rational and self- interested. This model is found in the emergent fields of Algorithmic Mechanism Design (AMD) and Distributed Algorithmic Mechanism Design (DAMD), both of which introduce game-theoretic ideas into a computational system. We, as designers, must create systems (peer to peer search, routing, distributed auctions, resource allocation, etc.) that allow nodes to behave rationally while still achieving good overall system outcomes.
This paper has three goals. The first is to convince the reader that rationality is a real issue in peer to peer networks. The second is to introduce mechanism design as a tool that can be used when designing networks with rational nodes. The third is to describe three open problems that are relevant in the peer to peer setting but are unsolved in existing AMD/DAMD work. In particular, we consider problems that arise when a networking infrastructure contains rational agents.


Learners Notes and Synthesis:
In our social environment every human being tends to protect its own self interest and survival at all cause. In order for a society to grow we should learn to be govern by protocols and rules. So with peer-to-peer network we cannot assume that every nodes will follow desired  protocols establish by the central authority or the developer of the application.

Some peer to peer application are govern by rules  and protocols:

* Routing to reach other peer
* Resource management
* Decision making based on facts and environment behavior
* Distribute load among other peer

Rationality vs  Self interest

Based on the example on this paper, running the auction on a large peer-to-peer network, initially you will. Be announcing the bidding for the auction and you are waiting for a lot of bids. But unfortunately there are only three bidders only to find out that they are your direct neighbors, for their self interest  of this neighbor they did not forward the advertisement for the auction.  This example illustrates basic problem  of peer-to-peer network  for rationality vs self interest.

Rationality in peer-to-peer network

Free rider problem:
“A free rider receives the benefit of everyone else's cooperation without having to cooperate himself. Think of a single person in the community who doesn't pay his taxes; he gets all the benefits of the public institutions those taxes pay for—police and fire departments, road construction and maintenance, regulations to keep his food and workplace safe, a military—without having to actually pay for them.” [1]

Tragedy of the commons  problems:
“A Tragedy of the Commons occurs whenever a group shares a limited resource: not just fisheries, but grazing lands, water rights, time on a piece of shared exercise equipment at a gym, an unguarded plate of cookies in the kitchen. In a forest, you can cut everything down for maximum short-term profit, or selectively harvest for sustainability. Someone who owns the forest can make the trade-off for himself, but when an unorganized group together owns the forest there's no one to limit the harvest, and a Tragedy of the Commons can result” [1]

In peer-to-peer system nodes that do not produce the same level of their consumption are considered leechers, while peers that  share the their resources to provide a better performance.
Another example peer to peer clients that deflect from protocols for their own interest are the user that develop their own client program that will deflect on the protocols and will circumvent the network for their own self interest.