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Etherchannel and switching loop
Leila99
Registered Users Posts: 1 ■□□□□□□□□□
in CCNA & CCENT
Hi guys,
I'm having a hard time understanding how layer 2 switching loop is prevented when using Etherchannel, I read that STP dont block port channels and thats caused me a lot of confusion.
For example if we have three switches and each switch is connected with the other by four links (we create a port channel out of these links). If sw1 send a broadcast message to sw2 (via port channel 1) and to sw3 (via port channel 2), then sw3 will send it back to sw1 after it receive it from sw2 (via port channel 3), this is a switching loop so what is the STP role here if there is no blocking ?!
Thank you
I'm having a hard time understanding how layer 2 switching loop is prevented when using Etherchannel, I read that STP dont block port channels and thats caused me a lot of confusion.
For example if we have three switches and each switch is connected with the other by four links (we create a port channel out of these links). If sw1 send a broadcast message to sw2 (via port channel 1) and to sw3 (via port channel 2), then sw3 will send it back to sw1 after it receive it from sw2 (via port channel 3), this is a switching loop so what is the STP role here if there is no blocking ?!
Thank you
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networker050184
Mod Posts: 11,962 Mod
STP will block an etherchannel the same way it will block a regular port. STP just treats all links in the etherchannel as a single port.An expert is a man who has made all the mistakes which can be made. -
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bharvey92
Member Posts: 419
Networker is correct, STP does treat Etherchannel's as a single port. The only way you could get around this by using L3 Port-Channels or technologies like FabricPath - but that's a different kettle of fish
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