On Oct 9, 11:55 am, Markus <markus.hofm...@gmail.com> wrote:
> Hi Skybuck,
>
> "The ip header contains a protocol field which specifies which other
> protocol
> is on top of it."
>
> You are right. The IP packet knows to my surprise which kind of data
> are transported. I was thinking that the IP header has no information
> about it.
>
> My other question I still have problems because I was thinking that on
> the application layer for example only HTTP data are received. The IP
> and port and the transport kind (TCP/UDP/ICMP) are removed. But there
> must be still a problem in my logic.

The application needs to keep track of each session, which it does
with a combination of source and destination IP address, source and
destination port IDs, protocol ID, and other identifying unique
numbers, such as the "Identifier" in ICMP Ping, for instance.

Bert