Which statement best describes OSPF external LSAs (type 5)?
A.
OSPF external LSAs are automatically flooded into all OSPF areas, unlike type 7 LSAs, which
require that redistribution be configured.
B.
External LSAs (type 5) are automatically changed to type 1 LSAs at ASBRs.
C.
Type 5 LSAs are route summaries describing routes to networks outside the OSPF
Autonomous System.
D.
External network LSAs (type 5) redistributed from other routing protocols into OSPF are not
permitted to flood into a stub area.
Explanation:
Type 5 – External LSA – these LSAs contain information imported into OSPF from other routing
processes.
They are flooded to all areas (except stub areas). For “External Type 1” LSAs routing decisions
are made by adding the OSPF metric to get to the ASBR and the external metric from there on,
while for “External Type 2” LSAs only the external metric is used. The link-state ID of the type 5
LSA is the external network numberhttp://en.wikipedia.org/wiki/Link-state_advertisement