[c-nsp] OSPF fast convergence

[Walter Keen]

When redesigning an OSPF service provider network, (default values, with
many gig-e links).  Aside from fixing link cost issues (100mbit is
treated the same as gig-e at the moment) should I look at sub-second
timers in OSPF 'ip ospf dead-timers minimal .....' Or BFD.  It looks
like either would require an IOS upgrade, but I have seen lots of
discussion about bugs in BFD.  This is only for core interfaces (all
cisco 7600 series).  We'll be adding MPLS and iBGP on top of this after
it's completed.