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Load balance

By Dusan Sladojevic ·

I Have an App server in my company that is the heart and brain for our business. I wanted to implement load balance between nic's to make server available to users even if one of the nic's fail, switch port fail or even switch fails. I was reading some stuff on internet and found that I should use IEEE 802.3ad Dynamic Link Aggregation. On Server I have both integrated Broadcom nic's and installed their Broadcom Advanced Control Suite (BACS) and configured those two nics to 802.3ad DLA. Both nics were on different switches. Everything worked ok. When I plug out cable from Active nic, other one takes job without interruption. Server was working a OK.
When I ping server every 20th or 50th ping doesn't come back. Which wasn't like before "operation". After month of usage those lost pings were increasing.
And I noticed that nics are not working simultaneously. Which was my wish to speed up receiving and sending packets.

So my question is - Am doing something wrong or when you implement load balancig you just have to lose some packets? And to mention I didn't change anything on switches (Both Cisco 2960G) which by the way aren't managed at all.

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A limitation of 802.3AD is:

by robo_dev In reply to Load balance

"A limitation of link aggregation is that all physical ports in the link aggregation group must reside on the same logical switch which in most scenarios will leave a single point of failure when the physical switch both links are connected to goes offline."

My guess is that there is a way to configure your Cisco switches to make this work. But as you have described it, it should not work.

One potential problem is the use of spanning tree protocol since multiple switches would form a network topology loop, which spanning tree would not allow.

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by Dusan Sladojevic In reply to A limitation of 802.3AD i ...

Thank you Robo_dev for your answer, I will try it in two weeks. I am going to holiday today :-)
I will move the other port to the same switch, and optionally make some port aggregation on cisco switch and will update for status.

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