Lab 3 (Edges)

[whyohwhyohwhy]

During the Edge Node design, it asks us to select the option that best fits the Justification:

 

"Enables ECMP because the edge virtual machine can uplink to the physical network over two different VLANs"

 

and the correct answer is: 

"For edge VM uplink traffic, use the default teaming uplink profile configured with the load balance by source port id policy (two active uplinks)."

However, the design course itself seems to heavily lean towards using traffic engineering via a named teaming policy. Given that with this option, the edge still has two distinct vlan/paths to each TOR via an active path, can we not use ECMP? Is it because each TOR is advertising totally different networks, so ECMP would not work here? Thanks

[whyohwhyohwhy]

No bites?

[Steffen Richter]

I think someone from the BU should look over that slide again and correct it.

ECMP = Equal Cost Multipathing

If its 1, 2 or whatever amount of VLANs, it does not directly relate to ECMP. 
Also, the uplink teaming does not directly relate to ECMP or no-ECMP. As you mentioned, that has something to do with traffic engineering/steering, knowing upfront where the traffic should flow and not interfere with each other etc..

[whyohwhyohwhy]

Sounds good. My point was that if each TOR advertises distinctly different networks, then ECMP would be redundant, as we could not make use of both TOR switches via hash to rotate traffic north to the same prefixes. Or have I misunderstood something? Thanks