questions about lacp

[sarahr202]

HI everybody!

I have few questions about lacp:

Assume default priority for switch and port which is 32768.Now lacp use mac address to decides the"master" and port number to decide which port will participate in etherchannel and which ones be put on stand-by.sw1's mac address< sw2'mac address, so sw1 is the master.

sw1 f1----------------f16 sw2

f2----------------f15

f3----------------f14

f4----------------f13

f5----------------f12

f6----------------f11

f7----------------f10

f8----------------f9

f9----------------f8

f10---------------f7.

sw1 now puts its ports from f0/1 through f0/8 in etherchannel and f0/9, f0/10 on stand-by. Which ports on sw2 will be included in etherchannel? Because of low port number, would sw1 allow f0/7 through f0/14 on sw2 in etherchannel? If yes , we get following:

sw1 f1(active)-----------f16(stand-by)SW2

f2(active)-----------f15(stand-by)

f3(active)-----------f14(active)

f4(active)-----------f13(active)

f5(active)-----------f12(active)

f6(active)-----------f11(active)

f7(active)-----------f10(active)

f8(active)-----------f9 (active)

f9(stand-by)---------f8(active)

f10(stand-by)--------f7(active)

If this is what we gonna get, then what's the use of port which is in etherchannel, connected to port on stand-by?

thanks a lot!

[Giuseppe Larosa · Accepted solution]

Hello Sarah,

the master decides what links are active and what are standby using its own point of view.

The other side should accept its decisions otherwise problems occur.

Or also the master concept would be useless otherwise.

So I expect both sides to agree on what links are active and what are standby.

Hope to help

Giuseppe