lagg/lacp poor traffic distribution

Eugene Grosbein egrosbein at
Sat Dec 18 19:13:56 UTC 2010


I've loaded router using two lagg interfaces in LACP mode.
lagg0 has IP address and two ports (em0 and em1) and carry untagged frames.
lagg1 has no IP address and has two ports (igb0 and igb1) and carry
about 1000 dot-q vlans with lots of hosts in each vlan.

For lagg1, lagg distributes outgoing traffic over two ports just fine.
For lagg0 (untagged ethernet segment with only 2 MAC addresses)
less than 0.07% (54Mbit/s max) of traffic goes to em0
and over 99.92% goes to em1, that's bad.

That's general traffic of several thousands of customers surfing the web,
using torrents etc.  I've glanced over lagg/lacp sources if src/sys/net/
and found nothing suspicious, it should extract and use srcIP/dstIP for hash.

How do I debug this problem?

Eugene Grosbein

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