Ofcourse, you are right. Thanks a lot!
julien.leproust@xxxxxxxx wrote:
oumer@xxxxxxxxxx a écrit :
Hi,
Here are few lines from tracing an hTTP connection. What I dont
understand is
there are some places where multiple packets have the same sequence
number
(sometime differening in that one has no data, just an ACK while the
other
duplicate will have a payload, OR in some other cases, the duplicated
packets
are acking different seq numbers.)
Can anyone tell me what is wrong, or what I am missing?
I haven't looked at the full trace, but that seems completely normal.
The sequence number is the number of bytes you have already sent,
including the payload of the current packet. That's why a packet with
no payload, only acking, has the same sequence number as the previous
one.
The acked sequence number is the number of bytes you have successfully
received. That's why it is the same in two consecutive packets sent if
nothing arrived in the reverse stream in the same time.
The sequence number and the acked sequence number refer to two
different stream, they are completely independent. You increment your
sequence numbers of the amount of data you send, and you ack the
sequence numbers you receive. You perfectly can ack data without
sending any payload, and send data without having received anything,
so nothing more to ack.
hth,
