LACP Server Side Question

[jean-christophe.valiere]

Hi Gurus,

I've a question regarding LACP configuration.

I've a server with 4 interfaces that are connected to 2 different switches (ie: eth0 & eth2 to switch1 and eth1 & eth3 to switch2).

On switch1 & switch2 interfaces are configured witch lacp.

Now, I'm wondering how I should configure network on the server side.

Either I bind all 4 interfaces together in one single bonding interface or I can bind eth0 & eth2 in one bonding interface and eth1 & eth3 in another bonding interface and then create a bridge on top of those 2 bonding interfaces (I will then have one bonding interface active and one in failover).

I'm wondering if both solutions are acceptable, if one is better than the other ?

Thanks and Best Regards,

Jean-Christophe

[Gabriel Hill · Accepted solution]

Hello Jean,

There are certain switching technologies that would allow you to combine all 4 interfaces, and make them one LACP etherchannel to different switches (Nexus VPC, or two 6500/4500 VSS Chassis, 3750 stack).

If these switches act independently, then you are only going to be able to bring two interfaces to one LACP etherchannel, and the other two interfaces to another LACP etherchannel. This would give you the active/failover scenario you mentioned.

Both this solutions are acceptable, of course depending upon the technology used for switching.

Cheer,
Gabriel

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[jean-christophe.valiere]

Hi Gabriel,

Thanks a lot for your answer.

As you slighly guessed, switches are 2960G, so I can't aggregate all interfaces in one etherchannel.

I'm wondering, if I aggregate all 4 interfaces on the server side, I won't be able to have more that 2 links avaible at a time - correct ?

Now, since switches are configured with pvst spanning-tree and my server will have multiple vlan interfaces configured, having all for interfaces in one single bond will allow to have some vlan going through one etherchannel and other vlan going through the other etherchannel - correct ?

If all the above, is correct, having all 4 interfaces binded to a single bond on the server, will allow to have vlan interface using the full 4 interfaces at the same time ?

Thanks and Best Regards,

Jean-Christophe

[Gabriel Hill]

Hello Jean,

I can't say I have much experience configuring a server-side etherchannel so I may miss the mark on this reply. But I suspect that in your case, configuring the server with all 4 interfaces in one etherchannel will not get you the desired results, and would not work (I would bet the switch would suspend the ports).

In regards to configuring two separate etherchannels on the server. Since you said you have multiple vlans interfaces on that server, I assume you can configure which vlans you want on each etherchannel (on the server side). This would allow you to have one etherchannel going to SW1 hosting (ex: vlan 1,2,3) and the second etherchannel hosting (ex vlan 4,5,6). You could be active/active in this configuration.

Though, you may be sacrificing redundancy. As if SW1 goes down, vlan 1,2,3 will not be available on that server. Depending on your needs, an active/standby configuration on the server (if possible) would achieve the redundancy of one switch going down.

Thanks,
Gabriel

[jean-christophe.valiere]

Hi Gabriel,

Thanks a lot for all your answers.

--

Regards,

Jean-Christophe.