LACP vs Static

[Rishav Garg]

Hi All,

I want to know about static port channel negotiation. Because Lacp is dynamic protocol that will negotiate by reading each other mac address in specific header format eg like below

port-channel13
  System Mac=54-7f-ee-18-86-41
  Local System Identifier=0x8000,54-7f-ee-18-86-41
  Admin key=0x800d
  Operational key=0x800d
  Partner System Identifier=0x8000,0-2a-6a-2-6d-41
  Operational key=0xc
  Max delay=0
  VPC ID=13
  Aggregate or individual=1
  Member Port List=3

But i want to know how static port channel detect that partner system Ports is in one port channel even if we disbale STP also.

Kindly help here. Does it also read partner mac address . If yes, then in which format or through which protocol.

[Madhukrishnan Gopinathan Nair]

Hello Garg,

I haven't looked at any details, but as far as i know when you hardcode mode ON for channeling, it is not going to negotiate anything rather it hardcodes the port to always on. So if you mis-cable there is likely chance of traffic impact since it dont recognize any mis cabling/config error etc  so use it with caution. 

PS : I have not checked the behaviour but its my impression on it.

Hope this helps 

Thanks,

Madhu

[Nithyanandan P]

LACP sends LACPDU packets between switch ports but Static Etherchannel will not send any packets. It blindly add interface to etherchannel group if it is up.

It created issue for me that

SW1 ==== Media converter (Copper to Fiber) === Patch panel ==== Media converter === SW2

When another SW2 end port was down, still i could see Etherchannel was Up in SW1.

[Madhukrishnan Gopinathan Nair]

Hi Nithi,

This is exactly what I mentioned below that you have to use ON mode with caution.

Thanks for sharing a scenario also.

Thanks,

Madhu.