Two FE ports of both NE40 routers are connected through MSTP of Nortel; once APDP is enabled, both FE cannot ping to each other. Disabling APDP, both could communicate normally. However, everything goes well once MSTP of Huawei is enabled between two NE40 routers.
APDP for NE40 cannot be enabled at MSTP transmission plat of Nortel.
1.The MSTP transmission unit of Nortel does not support transparent transmission.
2. It is advisable for customer to change MSTP plat of Huawei as active, and enable APDP to realize fast switchover.
3. Put forward suggestions on products for optimization of protocol so that APDP could be widely used. Improved version is introduced by Huawei.
After APDP is enabled, one router transmits Ethernet frame, and the peer echoes with a response, at which point the MAC address is not changed. The transmission unit of Nortel is L2 one which will perform analysis on MAC address. Therefore, the same MAC address is mapped to two ports, so they could not ping to each other. Moreover, the transmission unit of MSTP of Huawei supports transparent transmission which transmit the data without any changes to the peer.
For such a problem, it needs to study the bottom layer of protocol, and locate the root reason through capturing packets on site.