Ad Hoc Routing Modeling and Mathematical Analysis ◾ 133
graph G (N, A), the set of flows x
ij
|
(i. j)∈A
is referred to as the flow vector. A path P in a graph is a
sequence of arcs P
1, k
≡ (1, 2, … , k), where k ≥ 2. A graph is connected if, for each pair of nodes
i and j, there is a path starting at i and ending at j. e routing algorithms calculate the optimal
routes obtaining paths where the flow vectors x
ij
are constrained between given lower and upper
bounds (i.e., b
ij
≤ x
ij
≤ c
ij
) in order to limit the available bandwidth for that flow. In fixed networks,
stability is good enough and the end-to-end packet delay and throughput capacity are the only
metrics to be optimized. ese metrics are known in fixed networks, providing an NP-complete