Lectures notes for 2010 - KTH

Still a problem?
A UDP with 8192 payload to echo port as seen on SuSE 9.2 linux 2.6.8-24:
No. Time Source Destination Protocol Info
37 3.020002 172.16.33.16 Broadcast ARP Who has 172.16.33.5? Tell 172.16.33.16
38 3.021385 172.16.33.5 172.16.33.16 ARP 172.16.33.5 is at 00:40:8c:24:37:f4
39 3.021422 172.16.33.16 172.16.33.5 IP Fragmented IP protocol (proto=UDP 0x11, off=4440)
40 3.021452 172.16.33.16 172.16.33.5 IP Fragmented IP protocol (proto=UDP 0x11, off=5920)
41 3.021480 172.16.33.16 172.16.33.5 IP Fragmented IP protocol (proto=UDP 0x11, off=7400)
3.021385-3.020002=.001383 sec. ⇒ 1.383ms for the ARP reply
All but the last 3 fragments are dropped! Including the initial echo request packet -- so in the fragments that do arrive you
don’t know who they are for -- because the first fragment was lost!
Maguire Still a problem? 4: 14 of 74
maguire@kth.se 2010.03.21 Internetworking/Internetteknik