1.6 Network Topologies & Architectures

Why are network topologies useful?

For planning a new network

For troubleshooting and understanding signal flow

Star / Hub and spoke Network

All devices are connected to a central device

Usually a switched ethernet

What is the most common network topology

Star / Hub and spoke

Mesh network

Multiple links to the same place

If one link fails it can use anotherWh

Where are mesh networks usually used

WANs

Benefits of mesh network

Redundancy

Fault tolerance

Load balancing

Hybrid Networks

Combination of multiple physical topologies

Most networks use this

Spine and Leaf architecture

All “leaf” switches connected to every higher “spine” switches

leaves do not connected to each other, nor do spinesB

Benefits of Spine and leaf acrhitecture

Simple cabling

Redundant

FastDi

Disadvantages of spine and leaf

additional switches may be costly

Point to point network

Common on old WAN

Can use with LAN to connect buildings

Three tier architecture

Very common

Includes:

Core: centre of network - web servers, databases, applications

Distribution: Midpoint of core and users - communication betweek access switches

Access: where users connect - end stations, printers

How is three tier architecture often layed out?

Connection between buildings

Collapsed core architecture

two tier architecture

Combines core and distribution layers

Advantages and disadvantages of collapsed core

Simpler, less expensive, less resilient

East west Traffic flow

Traffic between devices in the same data centre

fastN

North south traffic flow

Ingress/egress to an outside device

Different security posture to inside devices