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TCP ack message query in diameter communication


Hi Experts,

I need understanding on fundamentals. Whenever sender sends diameter message to receiver over TCP protocol - receiver will send tcp ack message.

However, I want to understand if it is diameter application which responds back with ack or it is OS (RHEL) TCP/IP stack which sends this ack message ?

If OS - what is application's role in "TCP ACK" message ?

Thanks in advance !

asked 17 Mar '17, 08:40

Vijay%20Gharge's gravatar image

Vijay Gharge
accept rate: 0%

2 Answers:


The application has no role in the TCP ACK message. TCP Acknowledgements are sent by the TCP stack, which is part of the kernel.

The TCP ACK packet tells the sender that the data packet was received. The kernel pulls the data segment out of the packet and puts it in the receive buffer, and the application can then read the data from the buffer.

answered 17 Mar '17, 08:45

Jim%20Aragon's gravatar image

Jim Aragon
accept rate: 24%

Thanks a lot for answer. Though Jasper's response was little ahead of you, your response helped in understanding this case in detail. Hence accepting your comments as answer. @Jasper: Thanks to you too !

(18 Mar '17, 00:39) Vijay Gharge

That's fine, no worries - it's not about who's the fastest, but which one helped the most. Jim's is better, simple as that ;-)

(18 Mar '17, 05:56) Jasper ♦♦


If you mean a TCP ACK packet (with zero TCP payload bytes), it is a packet coming from the OS stack, acknowledging incoming data. The application has nothing to do with it, it's all stack.

answered 17 Mar '17, 08:43

Jasper's gravatar image

Jasper ♦♦
accept rate: 18%