Mark Tinka wrote:
So, with hierarchical routing, routing protocols can
carry only rough information around destinations, from
which, source side can not construct detailed (often
purposelessly nested) labels required for MPLS.
But hosts often point default to a clever router.
The requirement from the E2E principle is that routers should be
dumb and hosts should be clever or the entire system do not.
scale reliably.
In this case, such clever router can ever exist only near the
destination unless very detailed routing information is flooded
all over the network to all the possible sources.
A router can't be clever on something, unless it is provided
with very detailed information on all the possible destinations,
which needs a lot of routing traffic making entire system not
to scale.
Masataka Ohta
