1.Both OSN 3500 and switch S5328 support master and slave mode LAG. change to master and slave mode on both sides to fix this problem On this condition , service and DCN protocol all pass through the master port.
2.Use out-of-band DCN, that is to say, use another fiber to connect OSN3500 with switchS5328 for DCN communication.
1.The condition OSN will be under management is that the PPPOE protocol negotiate successfully, it contains 3 messages: pppoe hello、pppoe req、 pppoe ack, which need to be transmitted and received by both sides successfully
2.Before switch upgrade, all the DCN messages sent from OSN1500 pass through switch 1-1 to OSN 3500 slot15-5, the shaking hand process is successful.
3.After switch upgrade, some arithmetic are optimized, switch S5328 transmit DCN message from different port of LAG (0/1/2 and 0/1/1). from the captured packet, OSN 3500 received pppoe hello, pppoe ack Message from slot15-5 and received pppoe req from slot4-2.
4.OSN can’t assemble the DCN message from these different ports. So PPPOE protocol negotiated unsuccessfully, it caused OSN 1500 lose management