Re: Has anybod done ethernet link aggregration on 7.3 with a server with two NICs going to two different switches?

IF the two switches are part of a switch stack then yes LCAP works across two switches. However if they are two independent switches then IBM i doesn't support that. Cisco for one does have a version of LACP that works across switches or routers but it's not supported by IBM i.

So the solution we utilize is to create a two port LCAP bundle using one port fomr each card to switch "A". Then create another two port LACP bundle using a second port from each card to switch "B". Then use a virtual IP that floats between the two LACP bundles.

That setup with let you tolerate a switch failure or a card/port/cable failure.

- DrF

On 1/22/2022 8:58 PM, Laurence Chiu wrote:

I have a P8 box with one 4 port NIC with two ports on each NIC going to two
different switches.



Each port has its own IP and then we use VIP to present only one external
IP. This is a legacy design, the goal being to handle port failures on the
switches but of course, the weak link is now the NIC.



I do have a a second NIC installed so could I have one port on NIC 1 go to
a port on switch 1 and one port on NIC 2 go to a port on switch 2 and so
handle both a switch failure as well as a NIC failure?



Doing some reading it seems (we run 7.3) it seems I could look at ethernet
link aggregation as per this link



https://www.ibm.com/docs/en/i/7.3?topic=ethernet-link-aggregation



but it’s not clear if that would work if there are two different switches
involved.



Alternatively could we just define the two lines for the two switch
connections with each having their own IP addresses, and then just VIP to
present one IP to the host? Then potentially if one NIC (or one switch
port) fails, then the second NIC is still running.


That should mean no need to do any switch configuration like Virtual LInk
Aggregation or stacking (I think). Problem is our network guys know the
switches but are used to Windows or Linux boxes connected to them, not
intelligent boxes like Power servers with their enhanced networking
capabilities