LAG Questions

[Daniel_Valera1]

Hi!

I want create a LAG configuration, but i have some questions.

1. can i configure it using ports to diferent slots?
2. once configured if the master port pass to down state , everything LAG link is down?

Regards

[cbuchenau]

Hi Daniel,

I assume this is about EXOS firmware (Summit switches or BD chassis). Yes, of course you can build a lag with ports on different blades / stack members. They have to be the same speed though, e.g. 2 x SFP 1 Gig. And when the Master goes down, the LAG remains active!

For the record, with EOS you might want to enable singleportlag, to ensure that a 2-port LAG still remains active when 1 link fails / gets removed.

[Erik_Auerswald]

EOS should be configured to disable LACP on all ports that are not intended to be used as part of a LAG. This is the default on the current hardware.

The "singleportlag" feature is needed after a LAG goes down completely (e.g. switch reboot) and then only one link comes up. Without "singleportlag" enabled, the link will not form a LAG, with "singleportlag" enabled it will.

With the older default of LACP active on all ports, single links connecting switches would form a LAG, until the number of supported LAGs on the switch was exhausted. The LAG number (lag.0.X) would be random, the configuration would often not be correct. Therefore EOS requires two links to form a LAG by default. It will still keep an established LAG as long as at least one participating port is active.

[Ijaz_Chughtai]

Hi Daniel,
Yes, you can have ports from different slots as long as the ports are off the same speed ... you cannot mix 1G with 10G.
If the master port goes down, one of the member ports takes over the LAG mastership. So having one port go down in a LAG does not break the entire LAG.

Hope this helps .

[Nick_Yakimenko]

1) within one stack - yes
2) no, you create virtual port - LAG - and it is "link up" while one of the ports, that belong to LAG, is linked

[Patrick_Voss]

Hello Daniel,

You can use any of the ports in a stack or a chassis to create a lag. If the master port goes down a new master port will take over.