I think that the argument here is that there is a real need to have
an aggregate 400Mbp/s "pipe" in service as opposed to 2 each 200Mbp/s
"pipes". To gain the redunancy that Mr. Dave suggests, would actually
encourage the deployment of -two- additional 400Mbp/s channels.
Then the economics arguments kick in.
Haven't been following this thread all that closely so pardon me if
this has already been dealt with.. but note the earlier comment from
mfs that the design constraints say loop free layer 2 topology. Which
means redundant links don't exist.