Why there are different series of Cisco routers and switches?

These are the categories available in Cisco Product list

Overview: Blade Switches

Cisco Nexus 4000 Series Switches

SFS Solutions for Blade Switches

Cisco SFS Solution for Dell

Campus LAN Switches - Access

Overview: Campus LAN Switches - Access

Cisco Catalyst 9400 Series Switches

Cisco Catalyst 9300 Series Switches

Cisco Catalyst 9200 Series Switches

Cisco Catalyst 4500 Series Switches

Cisco Catalyst 3850 Series Switches

Cisco Catalyst 3650 Series Switches

Cisco Catalyst 2960-L Series Switches

Cisco Catalyst 2960-Plus Series Switches

Cisco Catalyst 2960-X Series Switches

Cisco Edge Series

Cisco Meraki Cloud Managed Switches

Cisco Redundant Power Systems

Campus LAN Switches - Core and Distribution

Overview: Campus LAN Switches - Core and Distribution

Cisco Catalyst 9600 Series Switches

Cisco Catalyst 9500 Series Switches

Cisco Catalyst 6800 Series Switches

Cisco Catalyst 6500 Series Switches

Cisco Catalyst 6500 Virtual Switching System 1440

Cisco Catalyst 4900 Series Switches

Cisco Catalyst 4500 Series Switches

Cisco Catalyst 4500-X Series Switches

Cisco Catalyst 3850 Series Switches

Cisco Nexus 7000 Series Switches

Campus LAN Switches - Digital Building

Overview: Campus LAN Switches - Digital Building

Cisco Catalyst 3560-CX Series Switches

Cisco Catalyst 2960-C Series Switches

Cisco Catalyst 2960-CX Series Switches

Cisco Catalyst 2960-L Series Switches

Cisco Catalyst Digital Building Series Switches

Data Center Switches

Overview: Data Center Switches

Cisco Nexus 9000 Series Switches

Cisco Nexus 7000 Series Switches

Cisco Nexus 6000 Series Switches

Cisco Nexus 5000 Series Switches

Cisco Nexus 4000 Series Switches

Cisco Nexus 3000 Series Switches

Cisco Nexus 2000 Series Fabric Extenders

Cisco R Series Racks

Cisco RP Series Power Distribution Units

Data Center Network Management

Cisco Data Center Network Manager

Cisco Data Center Network Manager

Cisco Fabric Manager

Energy and Asset Management

Cisco Asset Management Suite

Cisco EnergyWise Technology

Industrial Ethernet Switches

Overview: Industrial Ethernet Switches

Cisco 2500 Series Connected Grid Switches

Cisco Catalyst IE3400 Heavy Duty Series

Cisco Catalyst IE3400 Rugged Series

Cisco Catalyst IE3300 Rugged Series

Cisco Catalyst IE3200 Rugged Series

Cisco Embedded Services 3300 Series Switches

Cisco Embedded Services 2020 Series Switches

Cisco Industrial Ethernet 5000 Series Switches

Cisco Industrial Ethernet 4010 Series Switches

Cisco Industrial Ethernet 4000 Series Switches

Cisco Industrial Ethernet 3010 Series Switches

Cisco Industrial Ethernet 3000 Series Switches

Cisco Industrial Ethernet 2000 Series Switches

Cisco Industrial Ethernet 2000U Series Switches

Cisco Industrial Ethernet 1000 Series Switches

InfiniBand Switches

Cisco SFS 3500 Series Multifabric Server Switches

LAN Network Management

Cisco Configuration Assistant (CCA)

Cisco Network Assistant

LAN Switches - Small Business

Cisco 550X Series Stackable Managed Switches

Cisco 350 Series Managed Switches

Cisco 350X Series Stackable Managed Switches

Cisco 250 Series Smart Switches

Cisco 220 Series Smart Switches

Cisco ESW2 Series Advanced Switches

Cisco Small Business 300 Series Managed Switches

Cisco Small Business 200 Series Smart Switches

Cisco Small Business 110 Series Unmanaged Switches

Cisco Small Business Smart Switches

Service Provider Switches - Aggregation

Cisco Catalyst 6500 Series Switches

Cisco Catalyst 4500 Series Switches

Cisco ME 4900 Series Ethernet Switches

Service Provider Switches - Ethernet Access

Cisco Catalyst 3750 Metro Series Switches

Cisco ME 1200 Series Carrier Ethernet Access Devices

Cisco Small Business Gigabit SP Switches

Virtual Networking

Overview: Virtual Networking

Cisco Application Centric Infrastructure Virtual Edge

Cisco Application Centric Infrastructure Virtual Pod

Cisco Application Virtual Switch

Cisco Nexus 1000V InterCloud

Cisco Nexus 1000V Switch for KVM

Cisco Nexus 1000V Switch for Microsoft Hyper-V

Cisco Nexus 1000V Switch for VMware vSphere

Cisco Nexus 1000VE

Cloud Networking Services

Cisco Cloud Services Router 1000V Series

Cisco Prime Virtual Network Analysis Module (vNAM)

Cisco Virtual Security Gateway

WAN Switches

Cisco IGX 8400 Series Switches

MGX Switches

Cisco MGX 8900 Series Switches

Cisco MGX 8850 Software

Cisco MGX 8800 Series Switches

Cisco MGX 8250 Software

Cisco MGX 8200 Series Edge Concentrators

 

Overview: Cloud Connectors

Cisco Unified Survivable Remote Site Telephony

Cisco Webex Cloud Connected Audio

Data Center Interconnect Platforms

Cisco Carrier Routing System

Cisco Catalyst 6500 Series Switches

Cisco Nexus 7000 Series Switches

Introducing the Cisco ASR 1000 Router Series

Industrial Routers

Cisco 2000 Series Connected Grid Routers

Cisco 1100 Series Industrial Integrated Services Routers

Cisco 1000 Series Connected Grid Routers

Cisco 900 Series Industrial Routers

Cisco 800 Series Industrial Integrated Services Routers

Cisco 500 Series WPAN Industrial Routers

Cisco Wireless Gateway for LoRaWAN

Integrated Services Routers

Overview: Integrated Services Routers

Cisco 4000 Series Integrated Services Routers

Cisco 1900 Series Integrated Services Routers

Cisco 1800 Series Integrated Services Routers

Cisco 1000 Series Integrated Services Routers

Cisco 900 Series Integrated Services Routers

Cisco 800 Series Routers

Mobile Internet Routers

Cisco 5900 Series Embedded Services Routers

Network Functions Virtualization

Cisco 5000 Series Enterprise Network Compute System

Cisco Enterprise NFV Infrastructure Software

Cisco Integrated Services Virtual Router

Service Provider Core Routers

Cisco Carrier Routing System

Cisco Network Convergence System 6000 Series Routers

Service Provider Edge Routers

Cisco ASR 9000 Series Aggregation Services Routers

Cisco ASR 920 Series Aggregation Services Router

Cisco ASR 901 Series Aggregation Services Routers

Cisco ASR 900 Series Aggregation Services Routers

Cisco Network Convergence System 500 Series Routers

Cisco Network Convergence System 500 Series Routers

Introducing the Cisco ASR 1000 Router Series

Service Provider Infrastructure Software

Cisco WAN Automation Engine (WAE)

Small Business Routers

Cisco 1900 Series Integrated Services Routers

Cisco 900 Series Integrated Services Routers

Cisco 800 Series Routers

Cisco Small Business RV Series Routers

Virtual Routers

Cisco Cloud Native Broadband Router

Cisco Cloud Services Router 1000V Series

WAN Aggregation and Internet Edge Routers

Cisco Catalyst 6500 Series Switches

Cisco Network Convergence System 5500 Series

Cisco Network Convergence System 5000 Series

Introducing the Cisco ASR 1000 Router Series