Which two OSPF LSA types can be used to advertise routes between areas? (Choose two.)
A.
router
B.
network
C.
external
D.
summary
Explanation:
Type 3 – Summary LSA – an Area Border Router (ABR) takes information it has learned on one of its attached areas and it can summarize it (but not by default) before sending it out on other areas it is connected to. This summarization helps provide scalability by removing detailed topology information for other areas, because their routing information is summarized into just an address prefix and metric. The summarization process can also be configured to remove a lot of detailed address prefixes and replace them with a single summary prefix, also helping scalability. The link-state ID is the destination network number for type 3 LSAs.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 number.