Recently, a new explicit tower of function fields was introduced by Bassa, Beelen, Garcia
and Stichtenoth (BBGS). This resulted in currently the best known lower bound for Ihara's
constant in the case of non-prime finite fields. In particular over cubic fields, the tower's limit
is at least as good as Zink's bound; ie λ (BBGS/Fq3)≥ 2 (q2− 1)/(q+ 2). In this paper, the
exact value of λ (BBGS/Fq3) is computed. We also settle a question stated in Ihara's 2007
paper.

Recently, a new explicit tower of function fields was introduced by Bassa, Beelen, Garcia
and Stichtenoth (BBGS). This resulted in currently the best known lower bound for Ihara's
constant in the case of non-prime finite fields. In particular over cubic fields, the tower's limit
is at least as good as Zink's bound; ie λ (BBGS/F q3)≥ 2 (q 2-1)/(q+ 2). In this paper, the
exact value of λ (BBGS/F q3) is computed. We also settle a question stated by Ihara.