NETWORK TOPOLOGIES, ARCHITECTURES, AND TYPES - Unit 1

physical topology

actual layout of cables and network devices

network topology

way in which network appears to devices that use it

point-to-point connection (P2P)

direct network connection between exactly two devices where data travels across a dedicated link without being shared with other devices

star/hub and spoke topology

all computers and network devices connect to central device called hub or switch

• Each connected device requires a cable to be connected to hub, creating point-to-point connection

• Easiest to expand in terms of number of devices connected to network

star/hub and spoke advantage

• easily expanded without disruption to network

• cable failure only affects single user

• easy to troubleshoot and implement

star/hub and spoke disadvantage

• needs more cables than most topologies

• central connection device allows for single point of failure

• needs additional networking equipment to create network layout

mesh topology

each computer on network connects to every other, creating P2P connection between devices on network

• provides redundancy so better fault tolerance

mesh advantage

• provides redundant paths between LAN topologies

• network can be expanded without disruption to current users

mesh disadvantages

• needs more cables than other topologies

  • implementation is complicated

hybrid topology

creates redundant P2P network connection between specific network devices

spine and leaf topology

2-tier data center network design using spine switches (core) and leaf switches (access) for high scalability and performance; used in data centers

latency

typical amount of time it takes for packets of data to travel from one computer or system to the next; high is bad

equal latency

traffic always crosses the same number of devices (consistent hop count)

high redundancy

if a spine fails, only minor performance loss due to multiple alternate paths

collapsed core architecture

two tier network design that combines core and distribution layers from 3 tier model; commonly used in datacenters and medium sized enterprise networks

collapsed core benefits

simple design, cost effective, lower latency, scalable

collapsed core disadvantages

failure at collapsed core can impact entire network, scalability limits, design can cause congestion

North-South traffic flow

traffic flow between a client and external resources

exs: internet browsing, accessing cloud services

East-West traffic flow

relates to flow between internal resources within a network

exs: inter-server communication, database queries

Three-Tier Hierarchical Model

a structured approach to network design that breaks the network into three distinct layers; Each layer is designed to serve a specific purpose, optimizing scalability, performance, and maintainability

Core Layer (3 tier hierarchical model)

• backbone of network

• handles high-speed packet switching across entire network

• fast and reliable routing of data

• has high redundancy and fault tolerance

Distribution Layer (3 tier hierarchical model)

• intermediary layer between core and access layer

• manages routing, filtering, and WAN access

• aggregates data received from access layer switches

Access Layer (3 tier hierarchical model)

• network’s point of entry for devices and end users, connecting them to network

• includes switches and access points that provide connectivity to network devices