Collection<Link> linksList = nw1.nonnullLink().values();
// 1:EXPRESS-LINK 2:ADD-LINK 3:DROP-LINK
// 4:ROADM-To-ROADM 5:XPONDER-INPUT 6:XPONDER-OUTPUT
Collection<Link> linksList = nw1.nonnullLink().values();
// 1:EXPRESS-LINK 2:ADD-LINK 3:DROP-LINK
// 4:ROADM-To-ROADM 5:XPONDER-INPUT 6:XPONDER-OUTPUT