minimum frame size

[flokki123]

hi,

i was just playing around with wireshark a bit and saw that e.g. a arp request is only 42 bytes in length.

if i change the switching mode on my switch now from store-and-forward to fragment free, which should only switch frames with the minimum frame size for ethernet(64 bytes), would that mean that an arp request would be discarded?

how actually can it be that an arp request is only 42 bytes in length if the legal frame size for ethernet is 64 bytes?

thanks for any help,

florian

[fsebera]

Hi Florian,

I have also asked very similar questions here but found better responses on the Wireshark forums. You have to remember the tool viewing the data has its own display format and some of the header details are omitted for various reasons.  Visit http://www.wireshark.org/lists/wireshark-users/200708/msg00178.html (or go to google ans search for wireshark forums) for questions about Wireshark output for BEST results.

BTW, IPv4 uses MTU to specify the Maximum Transmission Unit while IPv6 uses MTU to specify the MINIMUM Transmission Unit - go figure.

HTH

Frank

[ebarticel]

Also I would like to add to the good response above that compression could be implemented as well on the link you capture the traffic.