xlii Answers to Assessment Test

Answers to Assessment Test

1.B. The command to enable MPLS on an interface is mpls ip. See Chapter 2 for more information.

2.C. Overlay VPNs evolved as a less expensive alternative to point-to- point connections. See Chapter 4 for more information.

3.D. External routes, OSPF LSA Type 5, are generated by ASBRs. See Chapter 7 for more information.

4.C. MP-BGP is configured between edge-LSRs or PE routers. See

Chapter 5 for more information.

5.B. E-BGP neighbors must be activated. See Chapter 8 for more information.

6.A. The LIB is a mapping of labels and resides in the control plane. See Chapter 1 for more information.

7.A. To enable VC merge on an ATM-LSR, use the mpls ldp atm vcmerge command. See Chapter 3 for more information.

8.B. After you associate an interface with a VRF, it loses its IP address. The IP address needs to be reconfigured. See Chapter 6 for more information.

9.B. VRF names are only applicable for the router on which they are configured. Therefore, they are locally significant. See Chapter 5 for more information.

10.A. With the MP-BGP (OSPF super-backbone), PE routers are viewed as ABRs. See Chapter 7 for more information.

11.B. The command to display label bindings in an MPLS environment is show mpls forwarding-table. See Chapter 1 for more information.

12.A. Cell-mode MPLS increments the TLV. Frame-mode MPLS decrements the TTL. See Chapter 3 for more information.

13.B. The first option after the maximum-routes command is the maximum number of routes allowed in the VRF. See Chapter 8 for more information.

Answers to Assessment Test xliii

14.B. In a peer-to-peer VPN, the service provider becomes responsible for routing protocol convergence. See Chapter 4 for more information.

15.B. Customer routers do not need MPLS functionality. An edge-LSR receives an unlabeled IP packet from CE routers and imposes a label. See Chapter 2 for more information.

16.C. A GRE tunnel is a Layer 3 VPN technology. An additional Layer 3 VPN technology is IPSec. See Chapter 6 for more information.

17.C. An LSC communicates with an ATM-LSR over VC 0/32. See Chapter 3 for more information.

18.B. The outgoing interface is mandatory when configuring a static VRF route, but the next-hop IP address is optional. See Chapter 8 for more information.

19.C. Cisco Express Forwarding (CEF) builds the FIB. The FIB resides in the forwarding plane of the MPLS architecture. See Chapter 1 for more information.

20.B. 32 total processes are available. Connected, RIPv2, and BGP all use only one process. OSPF uses a process for each individual VPN. See Chapter 7 for more information.

21.A. LSRs in the core of the network only need an IGP. Packets will be label-switched and not routed. See Chapter 2 for more information.

22.B. To configure an export route target, use the route-target export number command. See Chapter 6 for more information.

23.A, D. The two ways to implement peer-to-peer VPNs are dedicated router and shared router. See Chapter 4 for more information.

24.B. From inside BGP configuration mode, the address-family vpnv4 command is used to begin the MP-BGP configuration. See

Chapter 5 for more information.

25.B. MPLS, the IETF version of Cisco’s tag switching, uses LDP to exchange labels between neighbors. See Chapter 2 for more information.

26.C. On an ATM edge-LSR, as the sub-interface is configured, the point-to-point command option is applied for frame-mode MPLS. See Chapter 3 for more information.

xliv Answers to Assessment Test

27.C. A hub-and-spoke topology is often used by financial organizations because they usually have centralized resources that need to be accessed by remote branch offices. See Chapter 4 for more information.

28.B. Extended communities are required for MPLS VPNs. See Chapter 5 for more information.

29.A. To view the global routing table on a PE, the show ip route command is used. See Chapter 6 for more information.

30.D. OSPF routes from an external AS are OSPF LSA Type 5. See Chapter 7 for more information.