FreeBSD 10-stable (r274577) LACP / IEEE 802.3ad with TP-Link TL-SG2008 - not working

Thu Dec 18 01:36:32 UTC 2014

On Dec 17, 2014, at 5:19 PM, Alan Somers <asomers at freebsd.org> wrote:

>> 
>> 
>> This work great and without any issue.  All the defaults with 10-stable (r275778) and recent version of -head with this one line made it work.  Of course, this will likely break FreeBSD with all other switches LACP.
> 
> 
> I'm glad that you got your problem sorted out.  Please do let us know
> if you find a more general solution.
> 

Yeah, Alan - will do … if I decided to look into more.  That is why I was looking for spec on LACP.  One side is doing it wrong.  FreeBSD is looking for a LACPDU of exactly sizeof ( struct lacpdu ) which is 124 bytes. The TP-Link is sending a PDU of 128 bytes. I was hoping someone would know off hand what the spec says, if the PDU “should be” or “must be”.   I’m assuming this is an error on TP-Link’s firmware, and will try to file a bug with them if I can get to the root of the issue.  I’m assuming the Linux driver isn’t strict on the PDU size.

If this was really an error on the FreeSBD side … someone should have stumbled over long before I did.

> 
>> 
>> However, what I have also discovered this this switch is unlike FreeBSD which lagghash includes L4, the switch only seems to hash over SRC+DST IP or SRC+DST MAC.  Which makes it pretty much just sends all the traffic down one link from the switch. So for my particular use case with a small set of hosts, this switch is not useful for me.
> 
> 
> Actually, that's a fairly common problem.  I've even seen it on some
> expensive Cisco switches.

Yeah, in the end, this research and experiment has proven to me that LAGG/LACP is not likely the correct solution for this project.  10g Ethernet would work well, even back-to-back, but even used this looks to be a bit pricey for home/hobby setup.  I’m now looking towards Infiniband, as the cards and parts on the use market are a great value (but this is the wrong list for talking about that.)

Thanks !

-
David P. Discher
http://davidpdischer.com/
AIM: DavidDPD | Y!M: daviddpdz 