
164 Graph-Theoretic Algorithms for Energy Saving in IP Networks
6.2 ESACON Algorithm
A first GES algorithm described in this chapter is ESACON (Energy Saving
based on Algebraic CONnectivity) [3]. It models the Internet topology (i.e.,
the topology of an autonomous system in IP) with an undirected graph G =
(N, E), where N is the set of routers and E is the set of bidirectional links
connecting these routers.
ESACON is composed of two main steps:
1. the creation of an ordered list of links, denoted as L;
2. the identification of a set of links to be switched off, denoted as SL.
The pseudo-code in Algorithm 3 describes these two steps. As for step
1, the