Whether you have heard someone to configure a port channel or an ether channel they are basically the same thing. They refer to the way to aggregate multiple physical links, actually up to 8 physical links into a single logical interface (L2 or L3) to allocate more bandwidth than you would get by having a single one, not only meaning you can achieve fault tolerance, higher capacity, and load balancing but a piece of mind avoiding any bottlenecks.
EtherChannel refers to the technology whereas Port Channel it’s the interface name itself.
Said this let’s dig into some basic parameters to have in consideration when configuring a port channel:
- Maximum of 8 physical links per port channel, minimum 1
- Layer 2 with switch port mode (trunk/access) or L3 with IP address.
- Use same link speed, duplex and frame size on every physical link joining the Port channel.
- LACP mode uses active and passive mode versus PagP (Cisco’s Propietary) which uses auto and desirable modes.
- You could assign a different channel group number on each end, although this does not make any difference it’s recommended to use the same as a best practice.
A bit of background in how the port channel modes work:
In LACP the combinations you are looking for are: Active-Active or Active-Passive, a Passive-Passive configuration will never form a port channel.
Something similar happens with PagP you want to have it Desirable-Desirable or Desirable-Auto, never Auto-Auto.
There is a third method to configure an EtherChannel its static mode without negotiation, this means a port set in this mode will not negotiate with LACP nor PagP.
Consider a Port Channel created as an uplink using 4 links on each device, in this case, we are going to use VLAN 10 as the traffic crossing this link.
Port Channel interface creation
Port Channel physical interface adding
Have in mind that the port channel will not go up until you configure both ends, so you will have to do the same at the other end.
You can check on the port channel status running the command: