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.
