It is sometimes necessary to control which routes are advertised from OSPF into ISIS. This can be achieved by using a route-map when redistributing OSPF into ISIS.

ip prefix-list “access-nets” 0.0.0.0/0 id 2 ge 0 le 32
ip prefix-list “access-nets” 192.168.10.0/24 id 2 ge 24 le 24
ip prefix-list “access-nets” 192.168.20.0/24 id 2 ge 24 le 24

route-map “announce-access-nets” 1
permit
enable
match network “access-nets”
set injectlist “access-nets”
set metric-type type2
exit

router isis
redistribute ospf
redistribute ospf route-map “announce-access-nets”
redistribute ospf enable
exit

isis apply redistribute ospf