  Even if the benefit of implementing Software Product Lines is well
established, adopting such a large system is still a complex choice to make: it
is hard to implement, needs a good knowledge of market growth and a clear
vision of the enterprise objectives for long term. Therefore, many companies
remain unwilling to adopt such an approach, unless they gain flexibility and
get guarantees. Flexibility can be achieved by adopting an Agile Software
Product Line approach, to make sure changes are rapidly implemented and product
adapted to market evolution. Guarantees can be acquired by tracing elements and
the relations between them. However, tracing in Agile Software Product Line
context still needs to gain maturity as it is costly and therefore rarely
adopted. In this paper, we discuss the added value of traceability for Agile
Software Product Lines, and present our tracing model inspired from dynamic
network routing.
