[c-nsp] IOS-XR OSPF path selection

[Oliver Boehmer (oboehmer)]

>According to the IOS-XR documentation on OSPF:
>
>ASBR routes can be advertised as a Type 1 or Type 2 ASE. The difference
>between Type 1 and Type 2 is how the cost is calculated. For a Type 2
>ASE, only the external cost (metric) is considered when multiple paths to
>the same destination are compared. For a Type 1 ASE, the combination of
>the external cost and cost to reach the ASBR is used. Type 2 external
>cost is the default and is always more costly than an OSPF route and used
>only if no OSPF route exists.
>
>This seems to not be the standard behavior of IOS or NX-OS.  With IOS or
>NX-OS you can influence type-1 or type-2 routes via interface cost.  But
>in IOS-XR only type-1 are effected by interface cost, but not type-2.

huh? no compliant OSPF router (no matter which OS/brand) should consider
the cost to reach an ASBR when installing a type-2 external in its RIB, so
not sure what you mean by the above? can you give an example?
the ancient, but still valid OSPF Design Guide at
http://tools.cisco.com/squish/0D377 shows an example how E1 and E2s are
installed..
 
	oli