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New Member

Server with 3 NICs wants to connect to 2 switches

I have two 6509 on the distro layer ( distro 1 and distro2 ), running layer 2 only. They are connected to two 6509s on the core layer. One of the server admins has a 3 port NIC on his server bundled together to increase bandwidth. He wants to connect it to 2 ports on the distro1 and 1 port on the other distro2 switch. All 3 distro ports he is connecting to are in the same VLAN and the VLAN is allowed on all port channel connections between distro and core switches.


Will this even work since he is connected on different switches?


Yes this is possible with

Yes this is possible with Network Teaming, have a read of this:

Network Teaming must be setup correctly to ensure the same MAC address is NOT sent to two different switches/ports otherwise you will see flapping and packet loss.

If setup correctly on the Server side, the switches should see different MAC Addresses on all switchports connected to the same host.

VIP Purple

If the two switches run

If the two switches run individually, then it won't work. But you still can connect to ports on different line-cards. If the two switches run with VSS, then you can configure a channel to both switches at the same time.

New Member

Yes distro1 and distro2

Yes distro1 and distro2 switches are runing individually, they are connected via port channel and all vlans allowed. Are you saying it still won't work?

VIP Purple

he channel is only alloewd to

The channel is only allowed to a single switch (physical or logical). You can build a channel to a single switch, two switches running vss or (not your setup) different members of a switch-stack. But you can't run a channel to two individual switches. With that, the answer is "no", you can't.


Those stating that a NIC

Those stating that a NIC channel is not allowed to two individual switches should know that a NIC teaming is usually not a link aggregation (port-channel). If it is an active-standby-standby NIC team then all you need is to make sure all 3 ports belong to the same VLAN. Traffic will leave the server on the active link and the switches will learn that the MAC address is on this port. No Port-channel config is necessary on the switches.


Load-balanced NIC teaming usually requires Port-channel if the same src MAC address can appear on multiple ports. In this case multichassis link aggregation is mandatory and you cannot connect to individual switches.

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