why three times DUPAcks not trigger retransmission

asked 2020-05-13 01:13:10 +0000

client : server: I don't know why client is disconnected by server and client last few packets sent many dupacks to server ,but server not trigger retransmisson ,and tcp transmission is not recovered.could you please help me analyse it , thanks a lot! the pcap file:https://www.cloudshark.org/captu... https://www.cloudshark.org/captures/6...

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Your cloudshark link example only contains one side of the conversation, packets sent by the client.

Jim Young gravatar imageJim Young ( 2020-05-13 03:53:28 +0000 )edit

https://www.cloudshark.org/captures/1... server to client https://www.cloudshark.org/captures/6... client to server you download the original file,thank you very much.

lin7413271 gravatar imagelin7413271 ( 2020-05-13 04:21:11 +0000 )edit

Merging the egress10.pcap and ingress10.pcap files together yields a more useful capture to analyze.

Jim Young gravatar imageJim Young ( 2020-05-13 11:08:42 +0000 )edit

Where have you captured the data? For me it looks like something on the way between client and server is messing up the stream. Every 0,5 seconds a packet from the server is resend because the client didn't send a ACK or it was dropped on his way. And then suddenly a lot of client packets are retransmitted at once. Looks like the client also didn't received the ACKs from the server. But they're all in the capture. So something must drop the packets on the way.

The retransmissions from the server are also there. But delayed and all at once.

The stream gets terminated because of the missing ACKs, I guess.

JasMan gravatar imageJasMan ( 2020-05-13 19:53:06 +0000 )edit