The reconfiguration was too ambitious. It attempted simultaneously to introduce a new routing protocol and a new
See the Tutorial "Routing Principles and IOS Implementation Considerations" for a discussion of how routes are
chosen for routing table installation. The person writing this first configuration forgot that prefix length -- the number of
one bits in the subnet mask -- is considered before administrative distance.
While he correctly observed that OSPF's administrative distance is higher (i.e., less preferred) than IGRP's, he forgot
that the VLSM subnets introduced into the network were more specific, and thus preferable, to any IGRP route....