-- because when you only keep the routes of length 1,
-- you get a graph where every host can speak to any other host.
--
-- For example, S1--C1 is (l1,l2,l3) of length >1
-- But it's also S1--C1 = S1--R1, R1--R2, R2--C1 which are all of length 1
--
-- because when you only keep the routes of length 1,
-- you get a graph where every host can speak to any other host.
--
-- For example, S1--C1 is (l1,l2,l3) of length >1
-- But it's also S1--C1 = S1--R1, R1--R2, R2--C1 which are all of length 1
--