>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 ?
Corrct. That is a typo. Good catch.
Incidentally, there is more extensive background on the cost of
fragmentation in a Cabletron white paper at their site.
>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]
___________________________________
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]
