Marc, I don't think that this is relevant in this case because all interfaces are in a separate broadcast domain(separate virtual LAN). For example if I do "ping -c1 10.10.1.1" in T42 machine and run "tcpdump -nei eth0" in T42 at the same time, I see only one ARP reply as expected:
01:06:39.349959 00:16:41:54:01:93 > ff:ff:ff:ff:ff:ff, ethertype 802.1Q (0x8100), length 46: vlan 534, p 0, ethertype ARP, Request who-has 10.10.1.1 tell 10.10.1.2, length 28 01:06:39.350147 00:15:58:2a:84:3e > 00:16:41:54:01:93, ethertype 802.1Q (0x8100), length 64: vlan 534, p 0, ethertype ARP, Reply 10.10.1.1 is-at 00:15:58:2a:84:3e, length 46 Turned out, that the problem was with the switch interface MTU- it was smaller than laptop interfaces had. I increased the MTU and now iperf works. regards, Martin 2012/12/10, Marc Herbert <marc.herb...@gmail.com>: > Could this be relevant to your case? > > http://www.embedded-bits.co.uk/2008/multiple-network-gotcha/ > > > 2012/12/9 Martin T <m4rtn...@gmail.com>: >> Hello, >> >> I have a following simple network topology consisting of two laptops >> and one L2 switch facing with trunk ports to laptops: >> >> T60[eth0] <-> switch <-> [eth0]T42 >> >> >> Both T60 and T42 machines have three sub-interfaces: >> >> >> T60:~ # ip addr show | grep "eth0.[0-9]*$" >> inet 10.10.1.1/24 brd 10.10.1.255 scope global eth0.534 >> inet 10.10.2.1/24 brd 10.10.2.255 scope global eth0.541 >> inet 10.10.3.1/24 brd 10.10.3.255 scope global eth0.653 >> T60:~ # >> >> T42 ~ # ip addr show | grep "eth0.[0-9]*$" >> inet 10.10.1.2/24 brd 10.10.1.255 scope global eth0.534 >> inet 10.10.2.2/24 brd 10.10.2.255 scope global eth0.541 >> inet 10.10.3.2/24 brd 10.10.3.255 scope global eth0.653 >> T42 ~ # >> >> >> ..and L3 connectivity between laptops works fine: >> >> >> T60:~ # ping -I 10.10.1.1 -qc10 10.10.1.2 >> PING 10.10.1.2 (10.10.1.2) from 10.10.1.1 : 56(84) bytes of data. >> >> --- 10.10.1.2 ping statistics --- >> 10 packets transmitted, 10 received, 0% packet loss, time 8999ms >> rtt min/avg/max/mdev = 0.271/0.349/0.436/0.047 ms >> T60:~ # ping -I 10.10.2.1 -qc10 10.10.2.2 >> PING 10.10.2.2 (10.10.2.2) from 10.10.2.1 : 56(84) bytes of data. >> >> --- 10.10.2.2 ping statistics --- >> 10 packets transmitted, 10 received, 0% packet loss, time 8999ms >> rtt min/avg/max/mdev = 0.250/0.349/0.427/0.048 ms >> T60:~ # ping -I 10.10.3.1 -qc10 10.10.3.2 >> PING 10.10.3.2 (10.10.3.2) from 10.10.3.1 : 56(84) bytes of data. >> >> --- 10.10.3.2 ping statistics --- >> 10 packets transmitted, 10 received, 0% packet loss, time 8997ms >> rtt min/avg/max/mdev = 0.271/0.359/0.404/0.043 ms >> T60:~ # >> >> >> Both T60 and T42 have firewall disabled. >> >> I started three Iperf server processes in T60 with "iperf -s -u -fm -B >> 10.10.1.1 -p 5001", "iperf -s -u -fm -B 10.10.2.1 -p 5002" and "iperf >> -s -u -fm -B 10.10.3.1 -p 5003" commands: >> >> >> Proto Recv-Q Send-Q Local Address Foreign Address >> State PID/Program name >> udp 0 0 10.10.1.1:5001 0.0.0.0:* >> 6026/iperf >> udp 0 0 10.10.2.1:5002 0.0.0.0:* >> 5867/iperf >> udp 0 0 10.10.3.1:5003 0.0.0.0:* >> 5870/iperf >> >> Now if I start Iperf clients in T42 machine with "iperf -c 10.10.1.1 >> -fm -t20 -u -b 20m -p 5001", "iperf -c 10.10.2.1 -u -d -fm -t 120 -p >> 5002" and "iperf -c 10.10.3.1 -u -d -fm -t 120 -p 5003" commands, the >> server processes do not indicate that there has been a connection from >> Iperf client. Iperf clients just indicate that there was no ack >> received of the last datagram: >> >> [ 3] Sent 34015 datagrams >> [ 3] WARNING: did not receive ack of last datagram after 10 tries. >> >> >> For example if I execute "nmap -PN -sU -p 5001 --reason 10.10.1.1" in >> T42 I can see that Iperf server with PID 6026("iperf -s -u -fm -B >> 10.10.1.1 -p 5001") receives a connection. In addition, if I run >> "tcpdump -ni eth0.534 udp and port 5001" in T60 machine and execute >> "iperf -c 10.10.1.1 -fm -d -t20 -u -b 20m -p 5001", then I capture >> nothing with tcpdump. >> >> Iperf version both in T42 and T60 is 2.0.5. Any ideas what might cause >> such behavior? In case additional information is needed, please ask. >> >> >> >> regards, >> Martin >> >> ------------------------------------------------------------------------------ >> LogMeIn Rescue: Anywhere, Anytime Remote support for IT. Free Trial >> Remotely access PCs and mobile devices and provide instant support >> Improve your efficiency, and focus on delivering more value-add services >> Discover what IT Professionals Know. Rescue delivers >> http://p.sf.net/sfu/logmein_12329d2d >> _______________________________________________ >> Iperf-users mailing list >> Iperf-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/iperf-users > ------------------------------------------------------------------------------ LogMeIn Rescue: Anywhere, Anytime Remote support for IT. Free Trial Remotely access PCs and mobile devices and provide instant support Improve your efficiency, and focus on delivering more value-add services Discover what IT Professionals Know. Rescue delivers http://p.sf.net/sfu/logmein_12329d2d _______________________________________________ Iperf-users mailing list Iperf-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/iperf-users
