1. The FTP server is faulty.
2. The NE40E discards some data during data forwarding.
3. The link quality is poor.
1. Replace the FTP server. The fault persists.
2. Collect and send diagnostic statistics on the NE40E to the R&D personnel. No board discards packets.
3. Capture packets for analysis. The response time for a TCP packet is long.
In the environment with the 30 ms ping delay, capture and analyze packets as follows:
The number of exchanged packets returns to zero every around 20 ms. The network is idle for 10 ms. Click the idle part in the diagram to locate the packet details. After verification using the timestamp, the local end waits for around 10 ms for ACK packets from the peer end after sending FTP data packets.
Change the cost value of the NE40E and redirects traffic to another link to decrease the ping delay to 3 ms. Capture and analyze packets are follows: