IP Networking

I was analyzing a TCP snoop. And found following scenario

Code:

    From Server to Client ---> [PUSH,ACK] SEQ 2993 ACK 1744 WIN 8192 LEN 13
    From Server to Client ---> [PUSH,ACK] SEQ 3006 ACK 1744 WIN 8192 LEN 13
    From Client to server --> [ACK] SEQ 1744 ACK 3019 WIN 3304

I just want to know Why Packet 1 and 2 expecting same ACK. As we are Client I know that in Client Side Nagle is Enable. So Ideally Delayed ACK should be enable which is around 60ms. But in point 3 you can see client immediately sending ACK.

OS I am using is Solaris.

Can you guys please elaborate how its hapending. The server side has Real Time OS.

Moderator's Comments:

Please use code tags next time for your code and data.

What do you mean by packets expecting the same ack ?
ack's are not something you expect but something you acknowledge having received. There is nothing wrong for two packets to show the same ack value, especially here when the party hasn't sent anything in the meantime.

But in this case Client having TCP ack delay enabled. So solaris TCP is taking 70ms to send ACK for the previous message. But in this case I can see Solaris sending ACK immediately after receiving 2 message. That was my doubt.

There is no timing information in the snoop capture you posted.