Cisco 300-410 Practice Test - Questions Answers, Page 57

In EIGRP (Enhanced Interior Gateway Routing Protocol), a stub router is one that is connected to one or more neighbors and should not be a transit router1. The EIGRP stub routing feature improves network stability, reduces resource utilization, and simplifies the stub router's configuration1.

The network engineer wants to configure an EIGRP stub router that advertises only connected and summary routes. This can be achieved with the configuration provided in Option B:

router eigrp 100

eigrp stub summary

This configuration ensures that the EIGRP stub router advertises only connected and summary routes12. The summary keyword after the eigrp stub command indicates that the router should advertise only auto-summarized or statically configured summary routes12.

EIGRP STUB and Configuration - Cisco Community

EIGRP Stub And Summary Routes Explained - Networkel

In OSPF (Open Shortest Path First), the MTU (Maximum Transmission Unit) size must match on both sides of a link for OSPF neighbors to form an adjacency12.If the MTU sizes do not match, the OSPF adjacency will not form, and the routers will not become neighbors12.

In this case, R1 cannot establish a neighbor relationship with R2.One possible reason for this could be a mismatch in the MTU size on the interfaces of R1 and R212.

To resolve this issue, you can configure themtu ignorecommand on the interfaces of R1 and R2 (Option A).This command allows OSPF to ignore the MTU size when determining if it can form an adjacency with a neighbor12.This means that even if the MTU sizes do not match, OSPF will still form an adjacency, and R1 and R2 will become neighbors12.

OSPF MTU Mismatch - NetworkLessons.com

Understanding OSPF MTU Mismatch Conditions and Solutions - Cisco

The Label Distribution Protocol (LDP) plays a crucial role in MPLS (Multiprotocol Label Switching) networks.It enables label switch routers (LSRs) to exchange label binding information, which is essential for supporting hop-by-hop forwarding in an MPLS network1.

LDP establishes LSPs (Label Switched Paths) that follow the existing IP routing table2.This process is particularly well-suited for establishing a full mesh of LSPs between all of the routers on the network2.

When a packet arrives at a router in an MPLS network, the router looks at the incoming label, looks up the label in a table, and then forwards the packet to the next hop1.This method of label distribution is also called hop-by-hop forwarding1.

MPLS LDP (Label Distribution Protocol) - NetworkLessons.com

MPLS Label Distribution Protocol (LDP) - Cisco

What is Label Distribution Protocol (LDP)? - Metaswitch

Label Distribution Protocol - Wikipedia

What is MPLS LDP in networking? -- CCNA-Classes

Option B configures area 7 as a not-so-stubby area (NSSA) with theno-summaryoption on the area border router (ABR) R4. This allows the injection of external routes from EIGRP into the OSPF domain as type 7 LSAs, while preventing the propagation of inter-area summary LSAs into area 7.Theno-summaryoption also generates a default summary route for area 7, which can be used by R9 to reach the internet2.

Option A configures area 7 as a stub area, which does not allow any external routes or type 7 LSAs in the area.This prevents R9 from learning the EIGRP routes and accessing the internet3.

Option C configures area 7 as a NSSA without theno-summaryoption on R4. This allows the injection of type 7 LSAs into the area, but also allows the propagation of inter-area summary LSAs into the area.However, this option does not generate a default summary route for area 7, which means R9 has no route to reach the internet4.

Option D configures area 7 as a NSSA with thedefault-information originateoption on R4. This allows the injection of type 7 LSAs into the area, but also allows the propagation of inter-area summary LSAs into the area. Thedefault-information originateoption generates a type 7 default route for area 7, which can be used by R9 to reach the internet.However, this option is redundant and less efficient than Option B, because it injects both a type 3 and a type 7 LSA for the default route into the area5.

Option A configures uRPF loose mode to forward the packet. This mode allows the router to check if there is a route in the routing table that matches the source IP address of the incoming packet, regardless of the interface that is used to reach the source.This mode is suitable for networks that have asymmetric routing, where the incoming and outgoing interfaces for a packet may differ2.

Option B permits the 172.16.3.251 in the inbound ACL on interface gi0/3. This option does not resolve the issue, because it only allows the packet to pass the ACL check, but not the uRPF check.The packet will still be dropped by uRPF if there is no route to reach the source IP address via the same interface3.

Option C permits the 172.16.3.251 in the inbound ACL on interface gi0/3 to allow 172.16.3.251. This option is redundant and incorrect, because it repeats the same IP address twice in the ACL statement.It also does not resolve the issue for the same reason as Option B3.

Option D configures uRPF strict mode to forward the packet. This option does not resolve the issue, because it is the same mode that was already configured on the interface. Strict mode requires that the router has a route to reach the source IP address via the same interface where the packet was received.If this condition is not met, the packet will be dropped4.