Module 11: Network Design Flashcards
What are the key requirements for all enterprise networks?
Support critical applications, support converged network traffic, support diverse business needs, and provide centralised administrative control.
What is the Cisco Borderless Network framework designed to do?
Unify wired and wireless access, including policy, access control, and performance management across different device types.
What are the two proven hierarchical design frameworks for campus networks?
The three-tier layer model and the two-tier layer model.
What are the three critical layers in hierarchical network design?
Access layer, distribution layer, and core layer.
What is the function of the access layer in a hierarchical network?
It represents the network edge, where traffic enters or exits the campus network.
What is the function of the distribution layer in a hierarchical network?
It interfaces between the access layer and the core layer, implementing network foundation technologies such as routing, QoS, and security.
What is the primary purpose of the core layer in a hierarchical network?
To provide fault isolation and high-speed backbone connectivity.
In the two-tier layer model which two tiers remain?
Core/Distribution and Access
What are key recommendations for a basic network design strategy?
- Use expandable, modular equipment or clustered devices
- Design a hierarchical network with modularity
- Create a hierarchical IPv4/IPv6 address strategy
- Choose routers or multilayer switches to limit broadcasts and filter unwanted traffic.
How can redundancy be implemented in a scalable network?
By installing duplicate equipment with failover services for critical devices or creating redundant paths between key network components.
What are two methods of increasing bandwidth between devices in a scalable network?
Link aggregation (EtherChannel for Cisco, or vendor-neutral LACP) and equal-cost load balancing.
Why is a scalable routing protocol important in network design?
It helps isolate routing updates, minimises the size of the routing table, and improves network efficiency.
What is the role of link aggregation in a scalable network?
It allows administrators to increase bandwidth by creating one logical link made up of multiple physical links.
What is the function of switch blocks in a well-designed scalable network?
They act independently, limiting the size of failure domains and preventing a single device failure from taking down the entire network.
What factors must be considered when implementing a wireless network?
- Types of wireless devices
- Wireless coverage requirements
- Interference considerations
- Security
Why is OSPF a good choice for larger hierarchical networks?
It supports fast convergence, maintains neighbour adjacencies, synchronises link-state databases, and sends link-state updates when network changes occur.
What are the main categories of switches for enterprise networks?
Campus LAN, cloud-managed, data center, service provider, and virtual networking switches.
What are the three switch form factors?
Fixed configuration, modular configuration, and stackable configuration.
How is the thickness of a switch expressed?
In the number of rack units (RU) or sometimes just units (U).
What does the port density of a switch refer to?
The number of ports available on a single switch.
What do forwarding rates define in a switch?
The processing capabilities of a switch by rating how much data it can process per second.
What is Power over Ethernet (PoE)?
A technology that allows a switch to deliver power to a device over the existing Ethernet cabling.
Where are multilayer switches typically deployed in an organisation’s switched network?
In the core and distribution layers.
What are key characteristics of multilayer switches?
They build a routing table, support a few routing protocols, and forward IP packets at a rate close to that of Layer 2 forwarding.
What are key business considerations when selecting a switch?
- Cost
- Port density
- Power
- Reliability
- Port speed
- Frame buffers
- Scalability.
How do routers determine where to send packets?
They use the network portion (prefix) of the destination IP address to route packets to the proper destination.
What is the function of a router’s default gateway?
It is the local router interface that all hosts on a local network specify in their IP configuration to send traffic beyond the local network.
What are some key functions of routers?
- Provide broadcast containment by limiting broadcasts to the local network.
- Interconnect geographically separated locations.
- Group users logically by application or department.
- Enhance security by filtering unwanted traffic through access control lists (ACLs).
What are the main categories of Cisco routers?
Branch, network edge, service provider, and industrial routers.
What is the purpose of Cisco branch routers?
To optimise branch services on a single platform while delivering an optimal application experience across branch and WAN infrastructures.
What is the role of network edge routers?
They deliver high-performance, secure, and reliable services that connect campus, data center, and branch networks.
How do service provider routers benefit businesses?
They differentiate the service portfolio and increase revenues by delivering end-to-end scalable solutions and subscriber-aware services.
What makes industrial routers unique?
They provide enterprise-class features in rugged and harsh environments.
What are the two main router form factors?
Fixed configuration and modular routers.
What is the difference between fixed and modular routers?
Fixed configuration routers have built-in interfaces, while modular routers have multiple slots, allowing administrators to change interfaces as needed.
What are common router interface types?
- Fast Ethernet (100mb)
- Gigabit Ethernet (1gb)
- Serial
- Fiber-Optic
Which cost-effective physical network topology design is recommended when building a three-tier campus network that connects three buildings?
Extended star
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
What is the term that is used for the area of a network that is affected when a device or network service experiences problems?
Failure domain
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?
Network edge routers
Which design feature will limit the size of a failure domain in an enterprise network?
The use of the building swtich block approach
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
What is a function of the distribution layer?
Interconnection of large-scale networks in wiring closets
Which function is supplied by the access layer in a three-layer network design?
Network access
Which action should be taken when planning for redundancy on a hierarchical network design?
Add alternate physical paths for data to traverse the network.
What is a collapsed core in a network design?
A combination of the functionality of the distribution and core layers
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?
Core
Which technology is required when switched networks are designed to include redundant links?
Spanning Tree Protocol (STP)
Which feature could be used in a network design to increase the bandwidth by combining multiple physical links into a single logical link?
EtherChannel / LACP (link aggregation technologies)
Which statement describes a characteristic of Cisco Catalyst 2960 switches?
New Cisco Catalyst 2960-C switches support PoE pass-through.
Which network design solution will best extend access layer connectivity to host devices?
Implementing wireless connectivity
What is a definition of a two-tier LAN network design?
distribution and core layers collapsed into one tier, and the access layer on a separate tier
