Cisco® 300-420 Exam Practice Questions (P. 2)

GPT-4o - Answer

Regarding the OSPF configuration question, the use of a virtual link is necessary here because it addresses the challenge posed by the new branch office not being directly connected to area 0, the backbone area. OSPF requires that all areas must connect to area 0. In scenarios where this direct connection isn't feasible, virtual links effectively bridge the connectivity gap, ensuring all locations can exchange routes efficiently. This setup allows the new branch office in area 2 to route through area 1, which connects to area 0, maintaining the OSPF area requirement.

GPT-4o - Answer

In the context of managing EIGRP routes within the same autonomous system, distribute-lists offer a precise and straightforward mechanism to control which routes are advertised to neighbors. This method allows administrators to apply access control lists directly for route filtering, which is essential for maintaining a streamlined and efficient routing environment. Additionally, distribute-lists can match both standard and extended ACLs, providing flexibility in specifying exactly which routes should be transmitted or withheld. This targeted approach to route management helps in optimizing network performance and security. Other options like policy-based routing or route tagging serve different purposes, such as modifying routing policies or marking routes for specific handling, but do not inherently filter routes between EIGRP neighbors in the same manner.

GPT-4o - Answer

When designing an extensive EIGRP network with over 1000 routers, using a structured hierarchical topology and implementing route summarization are highly effective scaling techniques. This approach simplifies the network architecture and reduces the routing table size in routers, leading to better performance and manageability. Additionally, considering multiple EIGRP autonomous systems can help in partitioning the network into more manageable and smaller domains, which enhances scalability by limiting the scope of route calculations and exchanges to within smaller, controlled areas.

GPT-4o - Answer

Configuring each interface of an IS-IS router to operate as either Level 1 or Level 2, based on the specific adjacency requirements of each interface, effectively reduces unnecessary use of bandwidth and CPU resources. This setup minimizes the transmission of superfluous IS-IS hello packets across interfaces that do not require them, addressing both high CPU and bandwidth usage issues commonly observed in dual-level configurations. Such tailored configuration ensures operational efficiency and optimal utilization of network resources.

GPT-4o - Answer

EIGRP and BGP are indeed correctly identified as protocols supporting unequal cost load balancing. EIGRP handles this with its variance feature, allowing traffic to be split among multiple routes that are not necessarily of equal cost. BGP can achieve unequal cost load balancing by selectively manipulating route attributes such as AS-PATH, although this method is less straightforward than EIGRP's variance. The reference to IS-IS in the user comments pertains to Unequal Cost Multipath (UCMP), which is not typically synonymous with the general concept of unequal cost load balancing discussed in relation to EIGRP and BGP for the 300-420 exam.

GPT-4o - Answer

Indeed, tuning OSPF parameters can enhance the protocol's rapidity in adapting to network changes, resulting in better convergence times. Similarly, configuring non-backbone areas as stub areas effectively minimizes the routing table size in those areas. This reduction leads to less processing for routers and thus faster convergence. However, while the comments interestingly pointed towards using Bidirectional Forwarding Detection, it's important to verify if OSPF parameters and stub area configuration optimally address the specific exam question's focus on improving OSPF convergence directly through internal OSPF optimizations.

GPT-4o - Answer

In a totally stubby OSPF area, the area is configured to not receive type 3, 4, and 5 LSAs to minimize the size of the routing table. Instead, the area depends on a default summary route provided by the Area Border Router (ABR) to direct traffic intended for networks outside the area. This setup enhances router performance and simplifies management.