Module 11 - Network Design

As the network administrator you have been asked to implement EtherChannel on the corporate network. What does this configuration consist of?

• providing redundant links that dynamically block or forward traffic

• grouping multiple physical ports to increase bandwidth between two switches

• grouping two devices to share a virtual IP address

• providing redundant devices to allow traffic to flow in the event of device failure

Answer explanation

EtherChannel is utilized on a network to increase speed capabilities by grouping multiple physical ports into one or more logical EtherChannel links between two switches. STP is used to provide redundant links that dynamically block or forward traffic between switches. FHRPs are used to group physical devices to provide traffic flow in the event of failure.

What is a definition of a two-tier LAN network design?

• access and core layers collapsed into one tier, and the distribution layer on a separate tier

• access and distribution layers collapsed into one tier, and the core layer on a separate tier

• distribution and core layers collapsed into one tier, and the access layer on a separate tier

• access, distribution, and core layers collapsed into one tier, with a separate backbone layer

Answer explanation

Maintaining three separate network tiers is not always required or cost-efficient. All network designs require an access layer, but a two-tier design can collapse the distribution and core layers into one layer to serve the needs of a small location with few users.

What are the three layers of the switch hierarchical design model? (Choose three.)

• access

• distribution

• data link

• core

• network access

Answer explanation

The access layer is the lowest layer and it provides network access to users. The distribution layer has many functions, but it aggregates data from the access layer, provides filtering, policy control, and sets Layer 3 routing boundaries. The core layer provides high speed connectivity.

What network design would contain the scope of disruptions on a network should a failure occur?

• the installation of only enterprise class equipment throughout the network

• the configuration of all access layer devices to share a single gateway

• the reduction in the number of redundant devices and connections in the network core

• the deployment of distribution layer switches in pairs and the division of access layer switch connections between them

Answer explanation

One way to contain the impact of a failure on the network is to implement redundancy. One way this is accomplished is by deploying redundant distribution layer switches and dividing the access layer switch connections between the redundant distribution layer switches. This creates what is called a switch block. Failures in a switch block are contained to that block and do not bring down the whole network.

Which action should be taken when planning for redundancy on a hierarchical network design?

• immediately replace a non-functioning module, service or device on a network

• continually purchase backup equipment for the network

• implement STP portfast between the switches on the network

• add alternate physical paths for data to traverse the network

Answer explanation

One method of implementing redundancy is path redundancy, installing alternate physical paths for data to traverse the network. Redundant links in a switched network supports high availability and can be used for load balancing, reducing congestion on the network.

Refer to the exhibit. Which devices exist in the failure domain when switch S3 loses power?

• S4 and PC_2

• PC_3 and AP_2

• AP_2 and AP_1

• PC_3 and PC_2

• S1 and S4

Answer explanation

A failure domain is the area of a network that is impacted when a critical device such as switch S3 has a failure or experiences problems.

What are two benefits of extending access layer connectivity to users through a wireless medium? (Choose two.)

• increased flexibility

• decreased number of critical points of failure

• reduced costs

• increased bandwidth availability

• increased network management options

Answer explanation

Wireless connectivity at the access layer provides increased flexibility, reduced costs, and the ability to grow and adapt to changing business requirements. Utilizing wireless routers and access points can provide an increase in the number of central points of failure. Wireless routers and access points will not provide an increase in bandwidth availability.

A network designer is considering whether to implement a switch block on the company network. What is the primary advantage of deploying a switch block?

• A single core router provides all the routing between VLANs.

• The failure of a switch block will not impact all end users.

• This is a security feature that is available on all new Catalyst switches.

• This is network application software that prevents the failure of a single network device.

Answer explanation

The configuration of a switch block provides redundancy so that the failure of a single network device generally has little or no effect on end users.

What is a basic function of the Cisco Borderless Architecture access layer?

• aggregates Layer 2 broadcast domains

• aggregates Layer 3 routing boundaries

• provides access to the user

• provides fault isolation

Answer explanation

A function of the Cisco Borderless Architecture access layer is providing network access to the users. Layer 2 broadcast domain aggregation, Layer 3 routing boundaries aggregation, and high availability are distribution layer functions. The core layer provides fault isolation and high-speed backbone connectivity.

Which characteristic would most influence a network design engineer to select a multilayer switch over a Layer 2 switch?

• ability to build a routing table

• ability to aggregate multiple ports for maximum data throughput

• ability to provide power to directly-attached devices and the switch itself

• ability to have multiple forwarding paths through the switched network based on VLAN number(s)

Answer explanation

Multilayer switches, also known as Layer 3 switches, can route and build a routing table. This capability is required in a multi-VLAN network and would influence the network designer to select a multilayer switch. The other options are features also available on Layer 2 switches, so they would not influence the decision to select a multilayer switch.