Click the Exhibit button.
ISP1 has created an L3VPN to connect CE1 and CE2. The PE-CE routing protocol is OSPF.
Referring to the exhibit, which technology will allow CE1 to receive Type 1 and Type 2 LSAs from CE2?
A.
OSPF sham links
B.
RIB groups
C.
OSPF domain IDs
D.
OSPF virtual links
Explanation:
OSPF requires that all areas in an autonomous system (AS) must be physically connected to the backbone
area (area 0). In large networks with many areas, in which direct connectivity between all areas and the
backbone area is physically difficult or impossible, you can configure virtual links to connect noncontiguous
areas. Virtual links use a transit area that contains two or more area border routers (ABRs) to pass network
traffic from one adjacent area to another.
Incorrect Answers:
A: You can create an intra-area link or sham link between two provider edge (PE) routing devices so that the
VPN backbone is preferred over the back-door link. A back-door link is a backup link that connects customer
edge (CE) devices in case the VPN backbone is unavailable. When such a backup link is available and the CE
devices are in the same OSPF area, the default behavior is to prefer this backup link over the VPN backbone.
This is because the backup link is considered an intra-area link, while the VPN backbone is always considered
an interarea link. Intra-area links are always preferred over interarea links.
B: A RIB group is a way to have a routing protocol, in most cases, place information in multiple route tables.
C: When OSPF is used as the routing protocol on a provider edge to customer edge (PE-CE) link in a
multiprotocol label switching (MPLS) VPN. PE routers mark OSPF routes with the domain attribute derived from
the OSPF process number to indicate whether the route originated within the same OSPF domain or from
outside it. If the OSPF process numbering is inconsistent on PE routers in the MPLS VPN, the domain-id OSPF
mode command should be used to mark that the OSPF processes with different numbers belong to the same
OSPF domain.
http://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/47866-ospfdb7.html