I have been spending a lot of time looking at network dumps of SMPP traffic to assist in debugging some network issues. I was a bit rusty on some of the finer details of all the various TCP packet headers and my reference was at home. Google found an amazing resource on firewall.cx titled Anylising the TCP header.
The document spans 7 sections covering the following:
Section 1: Source & Destination Port Number
Section 2: Sequence & Acknowledgement Numbers
Section 3: Header Length
Section 4: TCP Flag Options
Section 5: Window Size, Checksum & Urgent Pointer
Section 6: TCP Options
Section 7: Data
It is beautifully colorful and well written. Something that can easily be passed on to someone who does not know a lot about networking or as a simple resource to just catch up on forgotten knowledge.
Firewall.cx has huge amounts of very good documentation on it, well worth poking around in for networking people.
