Hello dear Ankit , hope you are doing well ,! you are a wonderfull teacher , can you please advise me regarding E1 issue ? maybe the community from here will be able to help , we have changed the cables from server to ddf part , from ddf we have connected 4 STM1 and from there we go to MGW , the link was up and after changing we receive bad FCS and link is flapping often , why so ? Thank you