A network engineer is troubleshooting an OSPFv2 adjacency issue between two routers, R1 and R2, in Area 10. The show ip ospf neighbor command on R1 does not list R2. Both routers are confirmed to be in the same subnet, have unique router IDs, and are configured for Area 10. The OSPF hello timers are set to 10 seconds and dead timers to 40 seconds on both routers. Which of the following is the most likely cause for the adjacency failure?
Answer and explanation
Correct answer: A
For an OSPF adjacency to form, neighbors must agree on several parameters, including Area ID, timers, subnet, and area type. If one router is configured for a stub area and the other is not, their OSPF Hello packets will contain a mismatch in the stub flag, preventing them from forming an adjacency. MTU mismatch would cause the adjacency to get stuck in the EXSTART/EXCHANGE state, not prevent neighbor discovery. Authentication mismatch would show log messages about authentication failure. Process ID is locally significant and does not need to match.
Question 2
Multiple answers
A network administrator has configured a Layer 2 EtherChannel between two Catalyst switches using four FastEthernet links. The administrator used the channel-group 1 mode desirable command on both ends. After checking the status, it is observed that only three of the four links have bundled into the Port-channel. Which two factors could be preventing the fourth link from joining the bundle? (Select TWO)
Answer and explanation
Correct answers: B, C
For links to be bundled in an EtherChannel, they must have consistent configurations. Key parameters that must match include speed, duplex, native VLAN, and the list of allowed VLANs on the trunk. If one port has a different native VLAN, it will be suspended and cannot join the channel. Similarly, a port configured as an access port for a specific VLAN cannot be bundled with trunk ports.
Question 3
A branch office connects to the headquarters via a GRE tunnel. The tunnel interface on the branch router is configured as follows:
The branch router has a default route pointing to its ISP via GigabitEthernet0/1. Users at the branch office report they cannot reach servers at the headquarters (e.g., 10.10.10.10), which are reachable over the tunnel. A traceroute from the branch router to 10.10.10.10 shows the packets are being sent out the GigabitEthernet0/1 interface directly to the ISP, not into the tunnel. What is the most likely cause of this issue?
Answer and explanation
Correct answer: B
The router makes forwarding decisions based on its routing table. Even though the tunnel is configured, the router needs a specific route that directs traffic for the destination network (10.10.10.0/24) into the Tunnel0 interface. Without this route, the router will use the most specific matching route, which in this case is the default route pointing to the ISP. This causes the traffic to be routed to the public internet instead of being encapsulated in the GRE tunnel. Adding a static route like ip route 10.10.10.0 255.255.255.0 Tunnel0 would resolve the issue.
Question 4
A network administrator needs to provide default gateway redundancy for hosts in the 192.168.10.0/24 VLAN. Two multilayer switches, SW1 and SW2, are configured with SVIs for this VLAN. The administrator decides to use HSRP. SW1 should be the active router under normal conditions.
SW1 SVI Config: interface Vlan10 ip address 192.168.10.2 255.255.255.0 standby 1 ip 192.168.10.1 standby 1 priority 110 standby 1 preempt
SW2 SVI Config: interface Vlan10 ip address 192.168.10.3 255.255.255.0 standby 1 ip 192.168.10.1
What will be the result of this configuration?
Answer and explanation
Correct answer: A
In HSRP, the router with the highest priority value becomes the active router for the group. The default priority is 100. In this configuration, SW1 has a priority of 110, which is higher than SW2's default of 100. Therefore, SW1 will become the active router. The standby 1 preempt command on SW1 ensures that if it comes online after SW2 has become active, it will reclaim the active role due to its higher priority.
Question 5
True or False: In a properly configured multi-area OSPF network, an ABR (Area Border Router) will have a separate Link State Database (LSDB) for each area to which it is connected, plus one for the backbone area (Area 0).
Answer and explanation
Correct answer: A
This statement is true. A fundamental concept of multi-area OSPF is that an Area Border Router (ABR) maintains a separate and complete LSDB for each area it borders. This is how OSPF achieves scalability; routers within an area only need to know the detailed topology of their own area, and the ABR summarizes information between areas. Every ABR must be connected to Area 0, so it will always have an LSDB for Area 0 and at least one other non-backbone area.
Question 6
A network engineer is configuring a new switch stack using Cisco StackWise technology. Which of the following is a primary benefit of using a switch stack over configuring multiple standalone switches?
Answer and explanation
Correct answer: C
The most significant benefit of switch stacking is the simplification of management. A stack of switches operates as a single logical unit with one IP address for management, one configuration file, and a unified control plane. This drastically reduces administrative overhead compared to managing each switch individually. It also simplifies network topology by allowing for the creation of multi-chassis EtherChannels, which eliminates the need for Spanning Tree Protocol to block redundant links between the access and distribution layers.
Question 7
A technician is tasked with backing up the running configuration of a Cisco router to a TFTP server at 192.168.254.100. The technician enters the command copy running-config tftp: and is prompted for the server's address and a destination filename. Which command could achieve the same result in a single, non-interactive line?
Answer and explanation
Correct answer: B
Modern Cisco IOS allows for a URL-style syntax to specify the protocol, server, and filename in a single command. The format tftp:// / provides all necessary information to the copy process, avoiding the interactive prompts. This is useful for scripting and automation.
Question 8
A network administrator is configuring EIGRP for IPv6 on a router. Which command is used to enable the EIGRPv6 process on an interface?
Answer and explanation
Correct answer: C
Unlike EIGRP for IPv4 (and OSPFv2), which uses the network command under the router process to enable the protocol on interfaces, EIGRP for IPv6 (and OSPFv3) is enabled directly on the interface itself. The command ipv6 eigrp is entered in interface configuration mode to make that specific interface participate in the EIGRPv6 process.
Question 9
A company wants to establish a simple, single-homed BGP peering with its ISP to announce its public IP block. The company's AS number is 65500, and its public network is 198.51.100.0/24. The ISP's AS number is 12345, and the peering IP on the ISP side is 203.0.113.1. The company's edge router uses 203.0.113.2. Which set of commands correctly configures this basic eBGP peering and route advertisement?
Answer and explanation
Correct answer: B
The correct configuration requires several key elements: 1) The router bgp command must use the local AS number (65500). 2) The neighbor command must specify the peer's IP address (203.0.113.1) and their remote AS number (12345). 3) The network command is used to inject a route into BGP. It requires the exact network prefix and the corresponding subnet mask using the mask keyword. For the route to be advertised, it must exist in the router's routing table.
Question 10
Case Study
Company Background: Global Logistics Inc. (GLI) is a medium-sized shipping company with a central headquarters and three regional branch offices. The company is upgrading its network infrastructure to improve performance and reliability. The headquarters houses all central servers, including ERP and database systems. Each branch office has approximately 50 users who need constant access to these central resources. The network team consists of junior-level engineers who require a solution that is relatively simple to manage and troubleshoot.
Current Situation: The current network uses a Layer 2 design with a single VLAN spanning across all switches at each site. This has led to large broadcast domains and performance issues. At the headquarters, two core switches connect to an edge router, which provides internet access. The branches connect to the headquarters via MPLS links provided by a service provider. The company wants to move away from the flat Layer 2 design and implement a more structured, routed architecture.
Requirements:
Segment the network at each site into multiple VLANs (e.g., Users, Servers, Voice).
Enable routing between these new VLANs at each site locally.
The solution must be implemented on the existing Cisco Catalyst multilayer switches.
The routing protocol used between the core switches at HQ and the branch routers should be scalable and use open standards.
Management overhead for inter-VLAN routing configuration should be minimized.
Question: Given the requirements, which combination of technologies represents the most appropriate solution for implementing inter-VLAN routing at the headquarters and routing between sites?
Answer and explanation
Correct answer: D
This solution meets all requirements. SVIs are the modern, scalable method for performing inter-VLAN routing on multilayer switches, providing high performance without the bottleneck of a single router link (Router-on-a-Stick). OSPF is an open-standard, scalable link-state routing protocol suitable for connecting the HQ and branch sites. It is more advanced and scalable than RIPv2 and, being an open standard, is a better choice than the Cisco-proprietary EIGRP in many enterprise environments, especially when future vendor interoperability is a consideration.
