Networking - Etherchannel/STP

Posted on 2014-03-11
Last Modified: 2014-03-16
Hi, have few questions. Can you please answer ?

1. Why is it required to have all links of same speed, type and duplex settings to be grouped into a Etherchannel. Why not have different link speeds participate in a Etherchannel group and what are the actual effects of having different speed links in a Etherchannel. Will it have impact on performance ?

2. Can we configure STP and RSTP on the same switch ? Can we configure STP and RSTP on interface level ? And what will happen if we connect STP and RSTP switches back-to-back. What will be port states/roles on RSTP switch ?

Thanks !
Question by:msatyav10
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Accepted Solution

Don Johnston earned 250 total points
ID: 39922522
1). For whatever reason, the engineers that came up with link aggregation decided that all links must be the same.  If I had to guess, it's because since traffic can be sent over any links in the group, it wouldn't be very smart to have some traffic sent over a gig link and other traffic over a 100mbp/s link.

2) No. The STP type is a global parameter. RSTP is backwards compatible with legacy spanning tree. So if you connect a RSTP switch to a STP switch, the RSTP switchport dumbs down to a STP behavior.
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Expert Comment

by:Don Johnston
ID: 39932433
What part of my answer was incomplete?

Author Comment

ID: 39933263
Your answer was just fine. Sorry, I mean no disrespect.
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Expert Comment

by:Don Johnston
ID: 39933298
You should read the grading guidelines.

B is the grade given for acceptable solutions, or a link to an acceptable solution. A B grade means the solution given lacked some information or required you to do a good amount of extra work to resolve the problem. When closing the question, the asker should explain why a B grade was awarded.

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