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Jun 2nd, 2010
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Hello,


We have 8 Cisco switches that are all stacked, switch 1 is the top and 8 is at the bottom, should 1 also connect to 8?  As a frame in switch 1 that needs to go to switch 8 will have to pass through all the other switches to get there?

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Calin Chiorean Wed, 06/02/2010 - 04:30
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Andrew suggested good documentation. I advice you to read it.


Short answer: Yes, you should connecte 1 to 8 to achieve redundancy in the stack.

Andy White Wed, 06/02/2010 - 04:59
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Thanks, so in a nut shell if I do that how is the path selection determined from the master switch?  So if 1 needs to get to 8 then the master switch will tell the switch the quickest route through the stack?

Calin Chiorean Wed, 06/02/2010 - 05:18
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From:

http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps5023/prod_white_paper09186a00801b096a.html


To efficiently load balance the traffic, packets  are allocated between two logical counter-rotating paths.

The egress queues calculate path usage to help ensure  that the traffic load is equally partitioned.

Whenever a  frame is ready for transmission onto the path, a calculation is made to  see which path has the most available bandwidth. The entire frame is  then copied onto this half of the path. Traffic is serviced depending  upon its class of service (CoS) or differentiated services code point  (DSCP) designation. Low-latency traffic is given priority.

When a break  is detected in a cable, the traffic is immediately wrapped back across  the single remaining path.

Calin.

If this helps, please rate!

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