!Hola! > Same for the TCP header. there is an optional options field of 4 bytes. my s/4 bytes/4 bits/ ? And the size for options fields is 40 (2^15 * 4 - 20) bytes (the "data offset field" is sized to 4 bits) > quick glance through RFC 761 tells me this field never exceeds that 4 byte > length, but I am not very familiar with it. > ftp://ftp.isi.edu/in-notes/rfc761.txt Why did you refer 761 instead of 793 ? > I bring this up because most of the study materials state ex cathedra that > the IP and the TCP headers are 20 bytes. Having browsed the RFC's at one > time or another, I vaguely recalled the options, looked it up, and sure > enough, there they are. I don't recall much study material covering the > options and their uses. It has been a long time, but i believe that Comer talks about options. > Chuck Saludos, HoraPe --- Horacio J. Peqa [EMAIL PROTECTED] [EMAIL PROTECTED] [EMAIL PROTECTED] [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=13714&t=13714 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]