1. Which cost-effective physical network topology design is recommended when building a three-tier campus network that connects three buildings?
- dual ring
- extended star
Explanation: For efficiency, scalability, and cost-effectiveness, building an extended star topology from a centralized site to all other campus sites is recommended. A mesh topology is much more expensive, and bus and dual ring topologies are more difficult to troubleshoot and maintain.
2. How much traffic is a 48-port gigabit switch capable of switching when operating at full wire speed?
- 48 Gb/s, by providing full bandwidth to each port
- 1 Gb/s, because data can only be forwarded from one port at a time
- 44 Gb/s, due to overhead requirements
- 24 Gb/s, because this is the maximum forwarding rate on Cisco switches
Explanation: A switch operating at full wire speed is capable of switching the cumulative amount of each port on the switch. A 48-port gigabit switch could forward (48 x 1 Gb/s = 48 Gb/s) of data. Forwarding rates are determined based on the capabilities of each switch.
3. What is the term that is used for the area of a network that is affected when a device or network service experiences problems?
- collision domain
- user domain
- failure domain
- broadcast domain
Explanation: A failure domain is a portion of the network that is affected when a device or service fails or experiences problems.
4. Which type of router would an enterprise use to allow customers to access content anytime and anyplace, regardless of whether they are at home or work?
- branch routers
- network edge routers
- modular routers
- service provider routers
Explanation: Network edge routers provide customer interactivity, personalization, and mobility. Wherever customers can access an Internet connection, they can access their content. Branch routers provide simple network configuration and management while maintaining highly available networks. Modular routers are used to provide greater flexibility in which interfaces are used during network design and installation. Service provider routers provide end-to-end scalable solutions. Customers do not remotely access or connect directly to a service provider router.
5. Which design feature will limit the size of a failure domain in an enterprise network?
- the purchase of enterprise equipment that is designed for large traffic volume
- the installation of redundant power supplies
- the use of a collapsed core design
- the use of the building switch block approach
Explanation: In order to best limit the of a failure domain, routers or multilayer switches can be deployed in pairs. The failure of a single device should not cause the network to go down. Installing redundant power supplies may protect a single device from a power failure, but if that device suffers from another type of problem, a redundant device would have been a better solution. Purchasing enterprise equipment that handles large flows of traffic will not provide extra reliability in times of an outage. If a collapsed core design is used, the core and distribution are collapsed into a single device, increasing the chance of a devastating outage.
6. What is a function of the distribution layer?
- fault isolation
- network access to the user
- high-speed backbone connectivity
- interconnection of large-scale networks in wiring closets
Explanation: The distribution layer interacts between the access layer and the core by aggregating access layer connections in wiring closets, providing intelligent routing and switching, and applying access policies to access the rest of the network. Fault isolation and high-speed backbone connectivity are the primary functions of the core layer. The main function of the access layer is to provide network access to the user.
7. What is the function of PoE pass-through?
- allows switches, phones, and wireless access points to receive power over existing Ethernet cables from an upstream switch
- allows a multilayer switch to forward IP packets at a rate close to that of Layer 2 switching by bypassing the CPU
- allows multiple physical switch ports to be aggregated together and act as a single logical to increase bandwidth on trunk links
- allows a switch to disable redundant Layer 2 paths in the topology to prevent Layer 2 loops
Explanation: PoE or Power over Ethernet allows devices such as wireless access-points and IP phones to receive power from PoE enabled switch ports. PoE pass-through allows a switch to receive power from an upstream switch and pass it through to PoE devices.
8. Which function is supplied by the access layer in a three-layer network design?
- application of policies
- network access
- high-speed connectivity
- backbone connectivity
Explanation: The main purpose of devices in the access layer is to supply network access to end users. Distribution layer devices provide services such as routing and policy functions. The core layer provides high-speed backbone connectivity.
9. Which action should be taken when planning for redundancy on a hierarchical network design?
- Add alternate physical paths for data to traverse the network.
- Purchase backup equipment for every network device at the distribution layer.
- Immediately replace a nonfunctioning module, service ,or device on a network.
- Implement STP PortFast between the switches on the network.
Explanation: One method of implementing redundancy is path redundancy, which means installing alternate physical paths for data to traverse the network. Redundant links in a switched network support high availability and can be used for load balancing, thus reducing congestion on the network.
10. What is a collapsed core in a network design?
- a combination of the functionality of the access, distribution, and core layers
- a combination of the functionality of the access and distribution layers
- a combination of the functionality of the distribution and core layers
- a combination of the functionality of the access and core layers
Explanation: A collapsed core design is appropriate for a small, single building business. This type of design uses two layers (the collapsed core and distribution layers consolidated into one layer and the access layer). Larger businesses use the traditional three-tier switch design model.
11. What is the name of the layer in the Cisco borderless switched network design that is considered to be the backbone used for high-speed connectivity and fault isolation?
- data link
- network access
Explanation: The three layers of the Cisco borderless switch network design are access, distribution, and core. The access layer switches are the ones used to connect end devices to the network. The distribution layer switches accept connections from access layer switches and provides switching, routing, and access policy functions. The core layer is called the backbone and core switches commonly have high-speed redundant connections.
12. Which technology is required when switched networks are designed to include redundant links?
- Spanning Tree Protocol
- virtual LANs
- virtual private networks
- link aggregation
Explanation: Spanning Tree Protocol (STP) is required when switched networks include redundant Layer 2 links. VLANs, VPNs, and link aggregation are not related to link redundancy in network design.
13. Which feature could be used in a network design to increase the bandwidth by combining multiple physical links into a single logical link?
- trunk ports
Explanation: VLANs create several groups of users which use a single physical link. Trunk ports are single physical links. Subinterfaces allow one physical link to be used to create several logical links. EtherChannel provides the ability to combine multiple physical links into a single logical link.
14. Which statement describes a characteristic of Cisco Catalyst 2960 switches?
- New Cisco Catalyst 2960-C switches support PoE pass-through.
- They are best used as distribution layer switches.
- They do not support an active switched virtual interface (SVI) with IOS versions prior to 15.x.
- They are modular switches.
Explanation: Cisco Catalyst 2960 switches support one active switched virtual interface (SVI) with IOS versions prior to 15.x. They are commonly used as access layer switches and they are fixed configuration switches.
15. Which network design solution will best extend access layer connectivity to host devices?
- implementing wireless connectivity
- implementing redundancy
- implementing EtherChannel
- implementing routing protocols
Explanation: EtherChannel allows more data to be moved at the access layer, but does not provide network expansion. Redundancy is used to provide failover solutions but does not focus on network expansion. Routing protocols are not used to provide network expansion at the access layer. Wireless connectivity provides network access to a large number of users at the access layer.