Gossiping Gossip Framework Models

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Gossiping Gossip Framework Models

• Yaacov Fernandess
• Antonio Fernández
• Maxime Monod
• Vivek Rai
• Michel Raynal

2
Objectives

• Gossip framework.
• Encapsulates the common features of most gossip
  solutions.
• Generic in terms of the environment (physical
  network, failures, etc.).
• Model of service/problem specification
  (functionality, guarantees,).
• Computational model to evaluate efficiency (time
  and message complexity, ).
• Common terminology.

3
Gossip framework

• No exact definition of gossiping, but
• Cyclic execution scheme.
• In each cycle a node selects a subset of nodes
  (SelectPeers).
• Node exchanges information with this subset.
• Bounded processing and bounded bandwidth per
  cycle.
• Blueprint of the gossiping framework.

4
Architecture
SERVICE (functionality, robustness)
Send, Receive,
Environment (physical network, failures, comm.
cost, clocks, )
5
Architecture
SERVICE (functionality, robustness)
PROTOCOL
SelectPeer()
Communication primitives, etc.
Environment (physical network, failures, comm.
cost, clocks, )
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Architecture
SERVICE (functionality, robustness)
PROTOCOL
SelectPeer()
PROTOCOL
SelectPeer()
Communication primitives, etc.
Environment (physical network, failures, comm.
cost, clocks, )
7
Model of environment

• Basic model (asynchronous model for distributed
  computing).
• Restrictions on it, to be able to do something
  useful.

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Dynamicity

• Static One single problem to be solved.
• Dynamic Many problems (maybe infinite).
• Model of arrivals (stochastic, adversarial).
• Continuos problem.

9
Efficiency

• Static/dynamic
• Cycles.
• Messages.
• Bytes.
• Dynamic/continuous
• Stability?
• Competitiveness?

10
Questions

• Can the service be provided in a given
  environment?
• Can a gossip stack provide it?
• Has gossiping the same power than any distributed
  algorithm?
• How efficiently can the service be provided?