Does anyone know if a packet is fragmented, that the specific values in a field are replicated across all headers of the fragmented packets, or just the first one?
Meaning, if I have a packet that has IP Prec 5, and a router along the way has to fragment the packet, would it be so kind as to put IP Prec on all the headers? Steve ""Priscilla Oppenheimer"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > Mossburg, Geoff (MAN-Corporate) wrote: > > > > Thanks for clearing that up; > > No problem. > > > I don't mind being told I'm > > mistaken. I > > recently decided that the only way I'm really going to learn > > from this group > > is to take a chance on confirming what I THINK I know, and > > asking questions > > about what I DON'T know. :) A lesson in humility, to be sure. > > I know what you mean. I like to pretend to be an uber goddess of all things > tech, but to learn, I have to admit to lots of cluelessness in some areas. > It can be a bit painful, but definitely worth it! :-) > > Priscilla > > > GM > > > > -----Original Message----- > > From: Priscilla Oppenheimer [mailto:[EMAIL PROTECTED]] > > Sent: Wednesday, January 08, 2003 5:35 PM > > To: [EMAIL PROTECTED] > > Subject: RE: fragmentation question [7:60643] > > > > > > Mossburg, Geoff (MAN-Corporate) wrote: > > > > > > Someone correct me if I'm wrong: > > > > OK, you're wrong. :-) Look it up or use a protocol analzyer. > > > > > All the "fragments" have the TCP/UDP/IP headers, or else they > > > can't be > > > routed to their destination. > > > > Routing to their destination just requires the IP header, which > > is in each > > fragment. The TCP or UDP headers are not in the fragments, past > > the first > > one. The IP layer at the end device puts it all back together > > and hands the > > packet to the TCP or UDP layer. TCP or UDP get the full packet > > and can > > "route" it to the correct process, based on the destination > > port number. > > > > > "Fragmentation" is just a way of breaking up the data payload > > > into smaller > > > > Data payload from IP's point of view. > > > > > packets, but it puts individual headers on each packet. > > > MTU is the total size of each packet, including the header. > > > > The term isn't always used that way, though. > > > > > GM > > > > > > -----Original Message----- > > > From: Paul Dong So [mailto:[EMAIL PROTECTED]] > > > Sent: Wednesday, January 08, 2003 4:19 PM > > > To: [EMAIL PROTECTED] > > > Subject: fragmentation question [7:60643] > > > > > > > > > Hi All, > > > > > > Please shed a light on this as I am confused. > > > > > > Fragmentation for UDP/TCP: > > > * Only the first fragment contains the UDP or TCP header, not > > > the > > > sequencial fragments? > > > > > > Fragementation for IP packets > > > * every fragmented packet will contains ip header? > > > > > > MTU 1500 bytes, doesn't it mean the data payload can not > > exceed > > > 1500 > > > bytes or the whole packet size(payload+header) can not exceed > > > 1500 > > > bytes? > > > > > > Thanks in advance > > > > > > Paul Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=60924&t=60643 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
