Your right Priscilla :) Yea, your also right about the different layers, because at layer 3, you could have 0.
I found that "802.5 has no min packet size" "IEEE 802.3 networks have a minimum packet size that depends on the transmission rate. For type 10BASE5 802.3 networks the minimum packet size is 64 octets" "IEEE 802.4 networks have no minimum packet size. IEEE 802.4 networks have a maximum packet size of 8191 octets including all octets between the frame control and the FCS inclusive" http://www.freesoft.org/CIE/RFC/1042/10.htm -----Original Message----- From: Priscilla Oppenheimer [mailto:[EMAIL PROTECTED]] Sent: Wednesday, April 10, 2002 8:17 PM To: [EMAIL PROTECTED] Subject: RE: packet size [7:41079] At 06:00 PM 4/10/02, Brian Zeitz wrote: >Well, maybe the reason why its 64 bytes, is because of CSMA/CD >parameters call for 64 bytes. Would this make sense? No, it doesn't really make sense if you think in layers. ;-) And in fact, I'm sure I've seen a smaller IP packet than 64 bytes on Token Ring. What makes you think the minimum IP packet is 64 bytes? I haven't seen this in RFCs, but maybe you found such a thing. > Now what about CRC? >Is that extra bits, or is CRC part of CSMA/CD. The CRC is extra bits. It is not related to CSMA/CD, although a frame damaged by a collision will have a CRC error. >I am asking a lot of >questions today :O > >Looking at some of this, I am surpised how little Doyles Vol 1 and 2 >TCP/IP mention this stuff. It's layering. TCP/IP doesn't care about CSMA/CD. CSMA/CD is handled by the data-link layer. >Maybe its more for the CCIE outline. It is indeed. >-----Original Message----- >From: Priscilla Oppenheimer [mailto:[EMAIL PROTECTED]] >Sent: Wednesday, April 10, 2002 5:18 PM >To: [EMAIL PROTECTED] >Subject: RE: packet size [7:41079] > >The minimum size for an Ethernet frame is 64 bytes. This includes the >Ethernet header and FCS, but not the preamble or inter-frame gap. The >minimum Ethernet frame size has to do with the ability of a sender to >recognize a collision reflecting back from the other side of a >maximum-sized Ethernet segment, while still sending the frame. > >The minimum size for Token Ring is 18 bytes, if I recall. This includes >the >header and FCS, but not the starting or ending delimiter or the frame >status byte. > >I didn't know IP had a minimum, although RFC 791 does say that "Every >internet destination must be able to receive a datagram of 576 octets >either in one piece or in fragments to be reassembled." > >Priscilla > >At 04:05 PM 4/10/02, Larry Letterman wrote: > >64 bytes ... > > > >Priscilla is this correct... > > > > > >Larry Letterman > >Cisco Systems > >[EMAIL PROTECTED] > > > > > >-----Original Message----- > >From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of > >Brian Zeitz > >Sent: Wednesday, April 10, 2002 12:32 PM > >To: [EMAIL PROTECTED] > >Subject: packet size [7:41079] > > > > > >Oops I found the answer, I thought it was over 500, cause I was looking > >at IPV6 specs. > > > > > > > > > > Minimum Packet Size > > > > > >According to Ethernet specifications, the size of a packet should be > >between 64 Bytes and 1518 Bytes. Therefore, the minimum packet size is > >64 Bytes. >________________________ > >Priscilla Oppenheimer >http://www.priscilla.com ________________________ Priscilla Oppenheimer http://www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=41183&t=41079 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
