[Isis-wg] draft-ietf-isis-traffic-01.txt

[Tony Li]

|  Earlier, I pointed out what I though was a problem with the 24-bit metrics,
|  namely, that MAX_PATH_METRIC increased from 1024 to a much larger value.
|  
|  If you are running traffic engineering metrics in parallel with existing
|  TLVs, which value for MAX_PATH_METRIC should be used?  Must all routers
|  in the subdomain support the new TLVs before they are used at all,
|  to avoid routing loops that would occur if some paths exceed the smaller
|  MAX_PATH_METRIC?


Would inconsistent MAX_PATH_METRICs lead to forwarding loops?  Or to
blackholes? 

In any case, if you're going to run with both metrics, then in normal
operations, the metric would have to be smaller than 1024.  If it were to
exceed this, presumably due to an outage, then newer systems might find a
path while older systems didn't.  This would seem like a blackhole.

And of course, if everything is a new system, you have a valid path.

I'm not sure I see the problem.

Tony