IS-IS import policies block routes and prevent them from being installed in the routing table, but do not prevent the prefixes from being propagated in Link State PDUs (LSPs).
Nokia recommends that the user must exercise caution when configuring this feature. Failure to do so may cause unintended connectivity loss (black holes).
The following match conditions are supported for IS-IS import policies:
from level
from prefix-list
from protocol isis [all | instance instance]
from tag
The following actions are supported with IS-IS import policies:
accept (installs the matched prefixes into the routing table)
reject (blocks the matched prefixes from being added to the routing table)
next-policy
Actions that modify the metric value, RTM preference, or route tag value of an accepted IS-IS route may be present in a route policy but are ignored when that policy is applied as an IS-IS import policy.