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Feature #132
closedLatency about 4 times higher than without batman-adv
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Description
I'm having two batman-adv nodes here, they are both connected directly with each other over an ethernet cable. Doing a ping6 directly over the interfaces as well as 'batctl ping' look fine:
ping6 fe80::222:b0ff:fe44:9402%eth2 PING fe80::222:b0ff:fe44:9402%eth2(fe80::222:b0ff:fe44:9402) 56 data bytes 64 bytes from fe80::222:b0ff:fe44:9402: icmp_seq=1 ttl=64 time=0.855 ms 64 bytes from fe80::222:b0ff:fe44:9402: icmp_seq=2 ttl=64 time=0.876 ms 64 bytes from fe80::222:b0ff:fe44:9402: icmp_seq=3 ttl=64 time=0.854 ms 64 bytes from fe80::222:b0ff:fe44:9402: icmp_seq=4 ttl=64 time=1.27 ms 64 bytes from fe80::222:b0ff:fe44:9402: icmp_seq=5 ttl=64 time=0.897 ms 64 bytes from fe80::222:b0ff:fe44:9402: icmp_seq=6 ttl=64 time=0.856 ms 64 bytes from fe80::222:b0ff:fe44:9402: icmp_seq=7 ttl=64 time=0.867 ms 64 bytes from fe80::222:b0ff:fe44:9402: icmp_seq=8 ttl=64 time=0.856 ms ^C --- fe80::222:b0ff:fe44:9402%eth2 ping statistics --- 8 packets transmitted, 8 received, 0% packet loss, time 7001ms rtt min/avg/max/mdev = 0.854/0.916/1.273/0.140 ms
./batctl p 00:22:b0:44:94:02 PING 00:22:b0:44:94:02 (00:22:b0:44:94:02) 19(47) bytes of data 19 bytes from 00:22:b0:44:94:02 icmp_seq=1 ttl=50 time=0.51 ms 19 bytes from 00:22:b0:44:94:02 icmp_seq=2 ttl=50 time=0.55 ms 19 bytes from 00:22:b0:44:94:02 icmp_seq=3 ttl=50 time=0.49 ms 19 bytes from 00:22:b0:44:94:02 icmp_seq=4 ttl=50 time=0.68 ms 19 bytes from 00:22:b0:44:94:02 icmp_seq=5 ttl=50 time=1.42 ms 19 bytes from 00:22:b0:44:94:02 icmp_seq=6 ttl=50 time=0.50 ms 19 bytes from 00:22:b0:44:94:02 icmp_seq=7 ttl=50 time=0.48 ms 19 bytes from 00:22:b0:44:94:02 icmp_seq=8 ttl=50 time=0.53 ms ^C--- 00:22:b0:44:94:02 ping statistics --- 8 packets transmitted, 8 received, 0% packet loss rtt min/avg/max/mdev = 0.484/0.647/1.416/0.932 ms
(batctl even seems a little faster, maybe because it is layer 2 only?)
Now both routers have an IPv6-address from the same subnet and as there is physically just this one connection and as those nodes are neighbours, I'd expect a similar latency over the mesh (bat0). But instead the latency is much higher, about 2-10 times. To also being able to test TCP/UDP-pings despite ICMP-pings, I did the tests with traceroute instead:
ICMP:
traceroute -N 1 -q 10 -n -I fdef:ffc0:3dd7:f231:222:b0ff:fe44:9401 traceroute to fdef:ffc0:3dd7:f231:222:b0ff:fe44:9401 (fdef:ffc0:3dd7:f231:222:b0ff:fe44:9401), 30 hops max, 80 byte packets 1 fdef:ffc0:3dd7:f231:222:b0ff:fe44:9401 4.664 ms 9.693 ms 8.159 ms 7.773 ms 8.113 ms 3.789 ms 2.220 ms 8.162 ms 6.172 ms 8.099 ms
TCP:
traceroute -N 1 -q 10 -n -T fdef:ffc0:3dd7:f231:222:b0ff:fe44:9401 traceroute to fdef:ffc0:3dd7:f231:222:b0ff:fe44:9401 (fdef:ffc0:3dd7:f231:222:b0ff:fe44:9401), 30 hops max, 80 byte packets 1 fdef:ffc0:3dd7:f231:222:b0ff:fe44:9401 4.264 ms 5.868 ms 11.233 ms 9.532 ms 7.247 ms 9.261 ms 6.325 ms 9.233 ms 7.186 ms 3.743 ms
And with this one... there has to be something wrong, but I don't know what (tried it a couple of times, always a similar result):
UDP:
traceroute -N 1 -q 10 -n -U fdef:ffc0:3dd7:f231:222:b0ff:fe44:9401 traceroute to fdef:ffc0:3dd7:f231:222:b0ff:fe44:9401 (fdef:ffc0:3dd7:f231:222:b0ff:fe44:9401), 30 hops max, 80 byte packets 1 fdef:ffc0:3dd7:f231:222:b0ff:fe44:9401 64.652 ms 60.034 ms 67.315 ms 61.872 ms 57.888 ms 55.837 ms 68.168 ms 61.051 ms 61.146 ms 60.231 ms
Even udp-tracerouting/pinging to the own IPv6-address instead of the neighbour's one has such high latencies.
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