Comment 14 for bug 1877301

Hi slaweq:
About the last question, It's my nits, I just want to express that the upstream router need to set a dirct route before enable the feature. The command looks a little weird, this is result of I have no physical router then I do the POC with the linux namespace as a fake upstream rotuer, the l3-agent needn't to do anything on the upstream router. The other questions, to be speak frankly, I have not considered them before. I will to make some extra exexperiment, then commit a spec for it.