Hi group,
Just about finished this excellent paper but have
come across the following issue.
under the heading of "IP Fragmentation"
>>> SNIP
On a FDDI medium with a 4500 byte maximum frame size,
you have 4436 bytes available for payload in each
frame. This payload includes 8 bytes of LLC/SNAP, 10
bytes of IP, and 20 bytes of TCP. There are also 20
bytes of FDDI frame overhead.
In the ideal case, there is a single transmitter
sending sequential frames. The theoretical efficiency
is 98.5%. With a 1500 byte frame payload limit, the
transmitter would need to create three frames to carry
the same information. Since each frame would add a
packet, you would add the framing, LLC/SNAP, IP, and
TCP overhead on each packet. Adding two additional
frames adds 144 bytes of overhead at all affected
layers, a small amount of overhead when compared with
the overhead you would incur in fragmenting on WANs.
>>> END SNIP
>From the first paragraph.
I agree with 8 bytes of LLC SNAP.
and I agree with 20 bytes of TCP header.
But I think 10 bytes of IP should also be 20 ?
And the overall sentence should read that the
remaining header i.e 4500-4436 = 64 consists of
(8 + 8 + 8 + 20 + 20) = 64
(Dest mac + Source mac + LLC/SNAP + IP + TCP)
Can anyone confirm ?
Phil.
____________________________________________________________
Do You Yahoo!?
Get your free @yahoo.co.uk address at http://mail.yahoo.co.uk
or your free @yahoo.ie address at http://mail.yahoo.ie
___________________________________
UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html
FAQ, list archives, and subscription info: http://www.groupstudy.com
Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
