Taking this to the list, when we approached the motives for the basic
IPFRR and Loop Free alternates the gains were clear. We went from
possibly doing things in the wrong order to a logical approach and
As we evaluate more the complex IPFRR means, I am wondering how do we
evaluate comparing the techniques? I spoke with a few people and I think
many struggle with comparing the alternatives.
For single failure much of our literature refers to two measurements:
1)% of changed paths covered
2)% of traffic covered (we often assume a balanced traffic load and
equate to point 1).
Are these the only terms we should evaluate the improvement by?
A suggestion would be to look at the good put of traffic (sum of
delivered packets over the network at instants in time). I suspect in
many networks scenarios we are could have diminishing gains. For example
as we reach 100% coverage for single failures, can we not have still
have packets dropped due to momentary congestion (since packets on
alternate paths now take longer and less efficient paths)?
How do we formalize this (or other) measurements so we can evaluate the
techniques. In my opinion, I think a criterion like this is necessary
before we can evaluate next steps.
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