load balancing mode of a LAG

[harri_waltari]

I need to check the load balancing mode of the lags on the physical switches (ICX6610, 08.0.30t) facing our esxi cluster. On the cluster side, at the virtual switches, the balancing mode is currently "Source and destination IP address". The manual is a bit vague of the modes and I can't seem to find a command to modify the mode in the physical switch.

The manual says (a snippet...):

Layer 2 Bridged TCP/UDP: Source and destination MAC addresses, source and destination IP addresses, and source and destination TCP/UDP ports.
...
Layer 2 Bridged IPv4 TCP/UDP  Source and destination IP addresses, and source and destination TCP/UDP ports.

So what is the difference here with "bridged tcp/udp" and "bridged ipv4 tcp/udp"? And are those different, selectable modes?

Eg "src & dst ip address and tcp/udp port" is one of the possible selections on the cluster side. Would that be a better combination for icx?

[harri_waltari]

Simon, thanks for this. It really clarifies a bit.

So, if the mode in the switch is fixed to "Source and destination IP addresses, and source and destination TCP/UDP ports" and the modes available on the vsphere are (amogst others) "src and dst ip address", "src and dst ip address and tcp/udp port" or "src and dst tcp/udp port" would you think that "src and dst ip address and tcp/udp port" is the closest match? It may be obvious but I'm baffled with nuances here. Also how crucial are the actual effects of (slightly) wrong selection?

[simon_pollard]

Hi

I'm afraid I can't comment on the vsphere config. with any confidence as it's not something that I have any experience with, but from what you have described "src and dst ip address and tcp/udp port" looks like the best match to the ICX behavior. The only way to be certain with be to perform some testing which is not something that we would be able to do.

Hopefully someone else on here has some relevant experience and can share some real-world insights.

[harri_waltari]

Simon,

I understand. Thanks for your input.

[vu_pham_ghtztqm]

Hi Hwa - LAG hashing on ICX is locally significant on the ICX, its result will decide which port to map the egress traffic toward the ESX. Similarly, LAG hashing on ESX is locally significant on the ESX, its result will decide which port to map egress traffic toward the ICX. Since it's two independent process, so I believe the hashing algorithm doesn't  have to match between ICX and ESX.

Thanks,

Vu

[harri_waltari]

Hi Vu,
I'm thinking the returning traffic. Say, from the host the traffic is sent out via one interface and the return traffic is sent from the switch to the host via another interface because of different load balancing mechanism. And of course vice versa. Would this affect the performance of either devices?
If there is no effect, what is the point of having several load balancing algorithms at all?