Summary: Worm Versus Alert: Who Wins in a Battle for Control of a
Consider the following game between a worm and an alert1
over a network of n nodes.
Initially, no nodes are infected or alerted and each node in the network is a special detector
node independently with small but constant probability. The game starts with a single node
becoming infected. In every round thereafter, every infected node sends out a constant number
of worms to other nodes in the population, and every alerted node sends out a constant number
of alerts. Nodes in the network change state according to the following three rules: 1) If a worm
is received by a node that is not a detector and is not alerted, that node becomes infected; 2)
If a worm is received by a node that is a detector, that node becomes alerted; 3) If an alert is
received by a node that is not infected, that node becomes alerted.
We make two assumptions about this game. First, that an infected node can send worm
messages to any other node in the network but, in contrast, an alerted node can send alert
messages only through a previously determined, constant degree overlay network. Second, we
assume that the infected nodes are intelligent, coordinated and essentially omniscient. In other