The Cisco Catalyst is a family of multilayer network switches developed and manufactured by Cisco Systems, designed to deliver secure, scalable, and intelligent connectivity for enterprise campus LANs, branch offices, and data centers.[1] Following Cisco's acquisition of Crescendo Communications in September 1993—which marked the company's entry into the switching market—the first major product, the Catalyst 5000 series, was introduced in 1994 and pioneered high-performance Ethernet switching with features like VLAN support and Layer 3 routing.[2][3][4]Over its evolution, the Catalyst family has expanded to encompass a wide range of fixed, modular, and stackable switches tailored for diverse deployment scenarios, including access, distribution, core, and industrial environments.[5] Key series include the Catalyst 9000 family (including the 9300 and 9200 series) for high-end enterprise and stackable access switching in midsize and branch networks, the next-generation C9000 series (such as the C9350) introduced in 2025 for AI-ready networks, and rugged options like the IE series for industrial Ethernet applications.[6][7][8] These switches emphasize hierarchical networkdesign—core, distribution, and access layers—to optimize traffic flow and manageability in complex infrastructures.[9]Notable for their integration of advanced security features such as Encrypted Traffic Analytics (ETA) and macro-segmentation, Catalyst switches also support IoT proliferation, cloud-native operations, and AI workloads through compatibility with Cisco Catalyst Center for automated policy enforcement and analytics.[9][1] As of 2025, innovations in the 9000 and C9000 series enable speeds up to 400G, multigigabit Ethernet for Wi-Fi 7, and built-in automation to simplify IT operations in hybrid work models.[6][10] This comprehensive portfolio positions Catalyst as a foundational element in modern enterprise networking, powering secure and resilient digital transformations.[11]
History
Origins and Development
The Cisco Catalyst line originated in 1993 through Cisco Systems' acquisition of Crescendo Communications, a startup specializing in high-performance Ethernet switching technology for workgroup environments. This $95 million deal, completed on September 26, 1993, represented Cisco's first major acquisition and marked the company's strategic entry into the burgeoning LAN switching market, shifting focus from its core router business to address the growing demand for scalable Ethernet solutions in enterprise networks. Crescendo's innovative switching architectures formed the technological backbone of the Catalyst family, enabling Cisco to rapidly develop products that integrated seamlessly with existing routing infrastructure.[3][12]Building on this foundation, Cisco formally launched the Catalyst series in 1994, with the Catalyst 5000 series debuting as a flagship offering of modular, chassis-based switches optimized for LAN backbone deployments. The 5000 series featured expandable designs supporting up to 5 or 9 slots for line cards, allowing network administrators to customize configurations for high-density port requirements in central wiring closets or data centers. This modularity addressed the limitations of fixed-configuration devices prevalent at the time, providing flexibility for evolving network topologies.[13][14]From the outset, the Catalyst line was positioned as a high-performance alternative to shared-media hubs and overtaxed routers, delivering dedicated bandwidth and low-latency switching for fast-growing enterprise LANs. By emphasizing scalability and wire-speed forwarding, these switches supported the transition from 10 Mbps Ethernet to higher-speed infrastructures, reducing bottlenecks in departmental and campus-wide networks. Early adopters, including large organizations and service providers, leveraged Catalyst for core aggregation, where traffic from multiple segments converged efficiently.[15]At launch, the Catalyst 5000 series introduced key innovations such as support for Virtual LANs (VLANs) via Cisco's Inter-Switch Link (ISL) protocol, enabling logical network segmentation without physical rewiring; Fast Ethernet (100 Mbps) interfaces for uplink and desktop connectivity; and foundational multi-layer switching capabilities through optional route-switch modules that integrated Layer 3 routing functions directly into the switch fabric. These features enhanced network security, performance, and manageability, setting the stage for Catalyst's dominance in enterprise switching.[14]
Major Milestones and Evolution
The Cisco Catalyst line experienced significant expansion in the 2000s, with the introduction of the Catalyst 2960 series in 2005, designed specifically for access-layer switching in enterprise networks, offering fixed-configuration Layer 2 capabilities for cost-effective deployment at the network edge.[16] This was complemented by the launch of the Catalyst 3750 series in 2003, which pioneered stackable Ethernet switching, allowing multiple switches to operate as a single logical unit for simplified management and scalability in campus environments.[17]From 2005 to 2010, the Catalyst family shifted toward enhanced power delivery and higher-speed connectivity, exemplified by the Catalyst 3560 series introduced in 2004, which integrated Power over Ethernet (PoE) to enable simultaneous data and power transmission to devices like IP phones and wireless access points, reducing cabling complexity.[18] Subsequent enhancements in this period, including models within the 3560-E series announced around 2008, brought 10 Gigabit Ethernet support to access and distribution layers, facilitating faster backbone connections and supporting the growing demands of data-intensive applications.In the 2010s, Cisco advanced the Catalyst portfolio toward cloud-managed and software-defined architectures, culminating in the 2017 launch of the Catalyst 9000 series, which introduced intent-based networking capabilities for automated policy enforcement and network optimization.[19] These switches were engineered for compatibility with Cisco DNA Center, a centralized platform that uses analytics and automation to simplify network operations and enhance visibility across wired and wireless environments.Entering the 2020s, the Catalyst line has incorporated support for advanced wireless standards and intelligent operations, including integration with Wi-Fi 6 and Wi-Fi 7 access points within the Catalyst 9100 family to deliver higher throughput, lower latency, and better handling of dense device ecosystems.[20] By 2025, updates have emphasized AI-driven automation through enhanced DNA Center features for predictive troubleshooting and resource allocation, alongside sustainability initiatives such as ENERGY STAR certification for the Catalyst 9000 series, leveraging energy-efficient silicon to minimize power consumption and environmental impact.[21][22]
Operating Systems
Cisco IOS
Cisco IOS is a monolithic operating system originally developed by Cisco Systems and first shipped to customers in December 1992 with version 9.1.[23] It was adapted for Cisco Catalyst switches in the mid-1990s following Cisco's acquisitions of switching companies like Crescendo Communications, enabling Layer 3 routing capabilities in early models such as the Catalyst 5000 series via modules like the Route Switch Module (RSM), while Layer 2 switching was handled by CatOS (derived from Crescendo's Granatix OS). This adaptation marked a significant evolution from proprietary switch operating systems to a unified IOS-based environment, providing consistent management across Cisco's routing and switching portfolio. CatOS was used for core Layer 2 functionalities in early and some modular platforms, with full IOS unification occurring in later fixed-configuration switches.[24]Key features of Cisco IOS in Catalyst switches include a command-line interface (CLI) for configuration, which allows administrators to manage device settings through text-based commands. It supports fundamental Layer 2 functionalities such as VLAN segmentation using IEEE 802.1Q trunking for traffic isolation and Spanning Tree Protocol (STP) to prevent network loops by blocking redundant paths.[25] For Layer 3 operations, it includes basic routing protocols like OSPF to enable inter-VLAN routing and path optimization within switched environments.[26]The version timeline for Cisco IOS on Catalyst switches began with releases in the 12.x series for early access-layer models; for example, the Catalyst 2950 series primarily used IOS 12.1(22)EA14 as its final supported version, released in 2010.[27] Subsequent Catalyst platforms, such as the 2960-X series, supported IOS up to the 15.x train, with releases like 15.2(7)Ex providing enhanced stability and feature parity before the gradual shift to successor systems.[28]A primary limitation of Cisco IOS's single-image architecture is the requirement for a complete system reboot during software upgrades, which can disrupt network operations and limit in-service updates. This design choice prioritized simplicity but was addressed in later evolutions like Cisco IOS XE, which introduced modular components for more flexible maintenance.[29] Migration paths from classic IOS to IOS XE are available for many Catalyst models to leverage these improvements.
Cisco IOS XE
Cisco IOS XE is the modular operating system powering modern Cisco Catalyst switches, evolving from the legacy Cisco IOS to provide enhanced scalability and reliability in enterprise networks.[30] Released in 2010, it adopts a Linux-based kernel with independent processes, enabling a modular architecture that separates system functions into distinct components for improved fault isolation and maintainability.[31] This design supports in-service software upgrades (ISSU), allowing seamless updates without network downtime by upgrading control and data planes independently.[32]A core enhancement of IOS XE is its programmability features, which facilitate network automation through protocols like NETCONF and data modeling with YANG, introduced prominently from version 16.x onward.[33] It includes RESTCONF APIs for programmatic configuration and management, enabling integration with orchestration tools and reducing manual interventions in large-scale deployments.[34] Furthermore, IOS XE integrates natively with Cisco DNA Center for intent-based networking, supporting automated policy enforcement and analytics across Catalyst platforms.[35]For Cisco Catalyst switches, IOS XE versions 16.x and later are optimized for the 9000 series, delivering advanced capabilities such as SD-Access for software-defined segmentation and secure boot to verify image integrity during startup.[36] These versions ensure robust security through hardware-rooted trust mechanisms, preventing unauthorized code execution.[37] The architecture's separation of control and data planes enables parallel processing, where the control plane handles routing decisions while the data plane focuses on high-speed forwarding, optimizing performance in high-throughput environments.[38] This separation also underpins zero-touch provisioning (ZTP), allowing switches to automatically download configurations and images upon deployment without manual setup.[39]
Hardware Design
Interfaces and Connectivity
Cisco Catalyst switches feature a variety of physical interfaces designed to support diverse connectivity needs in enterprise networks. Fixed-configuration models, such as those in the Catalyst 9300 series, typically include 10/100/1000 Mbps Ethernet ports for standard access layer connections, with options for multigigabit Ethernet supporting speeds up to 2.5 Gbps, 5 Gbps, or 10 Gbps on models like the C9300-24UX to accommodate high-bandwidth devices such as Wi-Fi 6 access points.[40] Fiber optic connectivity is provided through Small Form-factor Pluggable (SFP) and SFP+ transceivers, enabling 1 Gbps, 10 Gbps, 25 Gbps, or 40 Gbps links, while higher-end models support QSFP for 40 Gbps or 100 Gbps uplinks, and recent 9000 series models like the 9300X and 9500X support 400 Gbps QSFP-DD transceivers for advanced data center connectivity.[40] Additionally, management interfaces include RJ-45 console ports for serial access and USB ports (mini-B or Type-C in recent models) for simplified configuration and file transfers.[41]These interfaces adhere to key IEEE standards to ensure interoperability and reliability. Ethernet ports comply with IEEE 802.3 specifications for speeds ranging from 10 Mbps to 100 Gbps, including support for auto-negotiation and full-duplex operation.[40]Power over Ethernet (PoE) capabilities follow IEEE 802.3af (up to 15.4W), 802.3at (up to 30W), and 802.3bt standards, with modern Catalyst 9300 UPOE+ models delivering up to 90W per port for Type 4 devices like pan-tilt-zoom cameras or high-power IoT endpoints, operating in 802.3bt mode by default.[42] Flow control is implemented via IEEE 802.3x, enabled by default on Gigabit Ethernet ports to prevent packet loss during congestion.[40]Connectivity options extend beyond basic ports to enhance scalability and flexibility. In modular chassis-based switches like the Catalyst 9400 series, uplink modules provide high-speed aggregation, such as 8x10G SFP+ or 2x100G QSFP28 ports, allowing seamless integration with core networks.[43] For stackable fixed switches, StackWise-480 cables—using proprietary stacking technology—connect up to eight units with speeds up to 480 Gbps bidirectional (up to 1 Tbps in 9300X models), enabling simplified management as a single logical device.[44]Transceiver compatibility is ensured through Cisco's validated modules, including copper SFPs like GLC-TE for 1000BASE-T over twisted-pair cabling up to 100 meters, with a comprehensive matrix for third-party optics adherence to MSA standards.[45]Expansion capabilities in chassis-based Catalyst models, such as the 6500 and 9400 series, rely on modular interface cards to customize port density and types. These include line cards like the WS-X6708-10G for 10 Gigabit Ethernet in legacy 6500 chassis or C9400-LC-48U for 48-port UPOE with multigigabit support in modern 9400 systems, allowing hot-swappable upgrades without downtime.[46] Such cards support breakout configurations, for instance, splitting a 40G QSFP+ port into four 10G SFP+ interfaces, to match evolving network demands while maintaining IEEE 802.3 compliance for all media types.[40]
Form Factors and Architecture
Cisco Catalyst switches are available in two primary form factors: fixed-configuration and modular. Fixed-configuration models, such as the 1U rack-mount designs exemplified by the 2960 series, provide a compact, all-in-one solution ideal for access-layer deployments in space-constrained environments like branch offices or classrooms, typically supporting 8 to 48 ports with integrated uplinks.[47] Modular form factors, such as the 19-inch chassis with multiple slots seen in the 6500 series, offer greater flexibility for core and distribution layers, accommodating line cards, supervisors, and power supplies in configurations ranging from 3 to 13 rack units (RU) to scale capacity as needed.[48] These designs ensure compatibility with standard 19-inch racks, facilitating easy integration into enterprise data centers and wiring closets.[43]At the core of Catalyst switch architecture lies a distributed design centered on application-specific integrated circuits (ASICs) for the switching fabric, enabling high-speed packet processing and forwarding. Modern series, such as the 9000 family, utilize Cisco's Unified Access Data Plane (UADP) ASICs, which integrate Layer 2/3 forwarding, security, and telemetry functions into a single chip, delivering throughputs up to 480 Gbps per ASIC in configurations like UADP 2.0.[49] These ASICs are complemented by x86-based CPUs (quad- or octa-core) with 8-16 GB of DDR4 RAM for control plane operations and up to 960 GB SSD storage for applications and logging, supporting programmable features via Cisco IOS XE.[50] Power supplies and cooling systems are integrated as field-replaceable units, with redundant fans ensuring operational continuity.[51]Scalability in Catalyst architecture is achieved through variable port densities and high-bandwidth interconnects, allowing deployments from small-scale 8-port setups to enterprise-grade systems exceeding 1,000 ports. Fixed models offer up to 48 ports per unit, while modular chassis support hundreds via line cards, with stacking technologies like StackWise combining up to eight units for logical expansion.[52]Backplane bandwidth scales from hundreds of Gbps in access switches to terabits in core models, such as 9.6 Tbps in multi-slot chassis, enabling non-blocking performance for high-density traffic.[50] This design supports growing network demands without requiring full hardware overhauls.Thermal and power management in Catalyst switches prioritize reliability and efficiency for data center environments. Redundant power supply units (PSUs), often Platinum- or Titanium-rated for over 90% efficiency, provide N+1 failover and capacities up to 3,200W per unit, with options for AC/DC inputs and Power over Ethernet (PoE) budgets exceeding 2,800W across ports.[49] Cooling employs hot-swappable fan trays with variable-speed operation and front-to-back or side-to-side airflow, monitored by thermal sensors to maintain optimal temperatures and prevent downtime.[50] StackPower technology further enhances redundancy by pooling power across stacked units in shared or redundant modes.[51]
Management Features
Configuration and Monitoring Tools
Cisco Catalyst switches support multiple configuration methods to facilitate initial setup and ongoing management. The primary interface is the Command-Line Interface (CLI), accessible via console port for direct physical connections, Telnet for unencrypted remote access, or Secure Shell (SSH) for encrypted remote sessions, enabling administrators to execute commands for VLAN configuration, port settings, and routing protocols.[53][54] A web-based Graphical User Interface (GUI) is available through tools like the built-in switch Web UI or Cisco Configuration Professional for Catalyst for managing multiple devices, allowing point-and-click configuration of features such as QoS policies and basic network discovery without CLI expertise.[55][56] For automation, Simple Network Management Protocol (SNMP) enables programmatic configuration via management stations, supporting versions 1, 2c, and 3 for secure read-write operations on MIB objects, alongside model-driven interfaces like NETCONF and RESTCONF using YANG data models on Cisco IOS XE.[57][58] These methods are supported across Cisco IOS and IOS XE operating systems on Catalyst platforms.Monitoring capabilities on Cisco Catalyst switches rely on standardized protocols to track performance, detect anomalies, and analyze traffic. Syslog provides event logging for system messages, errors, and alerts, which can be forwarded to a central server for archival and real-timeanalysis, helping administrators correlate issues like interface flaps or protocol failures.[59]NetFlow, particularly Flexible NetFlow, collects and exports flow data for traffic visibility, enabling bandwidth utilization studies and application performance monitoring without impacting switch throughput.[60] For detailed packet inspection, Switched Port Analyzer (SPAN) mirrors traffic from source ports to a destination port for local analysis, while Remote SPAN (RSPAN) extends this across VLANs and switches using dedicated VLANs, and Encapsulated RSPAN (ERSPAN) further allows monitoring over Layer 3 networks.[61][62]Integration with enterprise tools enhances centralized oversight of Catalyst switches. Cisco Catalyst Center serves as a comprehensive platform for discovering, provisioning, and monitoring multiple switches, offering dashboards for topology views, performance metrics, and automated compliance checks to streamline troubleshooting.[63] It aggregates data from SNMP, Syslog, and NetFlow, providing correlated alerts and root-cause analysis workflows.Best practices for Catalyst switch management emphasize secure and efficient procedures. Initial setup often uses the Express Setup wizard, accessed via a web browser after powering on the switch with default settings, to configure basic IP addressing, hostname, and management VLAN in a guided, step-by-step process.[64] For configuration backups and restores, Trivial File Transfer Protocol (TFTP) or Secure Copy Protocol (SCP) is recommended to transfer running or startup configs to/from a remote server, ensuring redundancy and quick recovery; for instance, the copy running-config tftp: command saves the active configuration.[65][66] Regular verification of backups and use of SCP for encrypted transfers mitigate risks during maintenance.
Security and Access Controls
Cisco Catalyst switches incorporate robust security and access controls to safeguard network infrastructure against unauthorized access and threats. These features leverage Layer 2 and Layer 3 protocols to enforce policies that protect both the switch itself and the connected network segments. By integrating authentication, filtering, and segmentation mechanisms, Catalyst devices enable administrators to implement defense-in-depth strategies, ensuring compliance with enterprisesecurity standards.Access controls in Cisco Catalyst switches primarily focus on authenticating and restricting device connectivity at the port level. IEEE 802.1X port-based authentication prevents unauthorized devices from gaining network access by requiring supplicants to authenticate via an authenticator (the switch) and an authentication server, such as RADIUS, before granting port access.[67]Port security limits the number of MAC addresses allowed on a port, dynamically learning or statically configuring them to block unauthorized endpoints and mitigate MAC flooding attacks.[68] Additionally, DHCP snooping filters untrusted DHCP messages by building a binding table of valid client IP-MAC-port associations, preventing rogue DHCP servers from distributing malicious IP assignments.[69]Threat mitigation features in Catalyst switches target common attack vectors through traffic inspection and suppression. Access Control Lists (ACLs) enable granular filtering of IP traffic based on criteria such as source/destination IP, ports, and protocols, allowing administrators to permit or deny packets at Layer 2 or Layer 3 interfaces to block unauthorized flows.[70] Storm Control monitors and suppresses excessive broadcast, multicast, or unicast traffic on ports, preventing network storms that could overwhelm bandwidth and cause denial-of-service conditions by enforcing rate thresholds.[71] IP Source Guard complements DHCP snooping by validating IP packets against the snooping binding database or static hosts, dropping spoofed traffic from non-authorized sources on untrusted interfaces.[72]Encryption and trust mechanisms ensure the integrity of the switch's boot process and enable secure traffic segmentation. Secure Boot verifies the authenticity of firmware during initialization using hardware-enforced checks, preventing the execution of tampered or unauthorized code by validating digital signatures embedded in Cisco IOS images.[73] Image Signing employs asymmetric cryptography, such as RSA with SHA-512 hashing, to digitally sign software images, allowing the switch to confirm their origin and unaltered state before loading.[74]Cisco TrustSec provides software-defined segmentation through Security Group Tags (SGTs), which classify endpoints into groups and propagate tags inline or via SXP protocol to enforce role-based access policies without relying on traditional VLANs.[75]For compliance, Catalyst switches support zero-trust architectures by integrating with Cisco Identity Services Engine (ISE), which serves as a policy decision point for continuous authentication and authorization across the network. This integration enables dynamic enforcement of least-privilege access, profiling of devices, and automated threat response, aligning with zero-trust principles that verify every access request regardless of origin. As of 2025, enhanced ISE capabilities on Catalyst platforms facilitate scalable zero-trust deployments, including macro- and micro-segmentation for hybrid environments.[76]
Stacking and Redundancy
StackWise Technology
StackWise is a proprietary stacking technology developed by Cisco Systems that enables multiple Catalyst switches to interconnect and function as a single logical unit, facilitating simplified network management and enhanced scalability in enterprise environments.[77] The technology employs a high-speed bidirectional stacking protocol over dedicated interconnect cables, creating a unified control and data plane across the stack members.[52] Initially introduced with the Catalyst 3750 series, StackWise uses special bidirectional cables to form a closed-loop architecture, providing up to 32 Gbps of total stacking bandwidth (16 Gbps per direction) for efficient traffic load balancing.[77]The cabling and topology of StackWise support flexible configurations, including chain or ring setups, with the ring topology offering inherent redundancy against single cable failures through subsecond failover mechanisms.[77] Up to nine switches can be connected in a single stack using these proprietary StackWise cables, which ensure reliable high-speed communication without requiring external switches or modules.[77] This design allows for increased port density by aggregating ports from multiple physical switches into one manageable entity, while the shared control plane enables centralized configuration, monitoring, and software upgrades as if managing a single device.[52]Over time, StackWise has evolved to support higher bandwidth demands in modern Catalyst series, particularly the 9000 lineup. For instance, StackWise-480 provides 480 Gbps of bidirectional stacking bandwidth and supports up to eight switches in a ring topology, enhancing performance for data-intensive applications.[52] Advanced variants like StackWise-1T deliver up to 1 Tbps of bidirectional bandwidth, also accommodating up to eight members, which significantly boosts throughput and scalability in campus and branch deployments.[78] These evolutions maintain the core benefits of simplified management and unified operation while addressing the needs of higher-speed networks.[52]
Primary Election and Failover
In Cisco Catalyst switch stacks utilizing StackWise technology, the primary switch, also known as the active or master switch, is elected based on a predefined set of criteria to ensure consistent and predictable leadership within the stack. The election prioritizes the switch that is currently active if one exists; otherwise, it selects the switch with the highest configured priority value, which ranges from 1 to 15 with a default of 1. If priorities are tied, the switch with the shortest uptime (start-up time) is chosen, and as a final tiebreaker, the switch with the lowest MAC address is selected. This priority can be configured via the Command Line Interface (CLI) using the command switch <number> priority <value>, allowing administrators to influence the election outcome for operational preferences.[44]The election process occurs either at boot time or dynamically in response to failures. During initial stack formation or a full reboot, all member switches participate if they power on within a 120-second election window, enabling a synchronized selection of the active switch followed by the election of a standby switch approximately two minutes later. Switches joining after this window do not participate in the initial election but can be considered for future reelections. In cases of active switch failure, removal, or reset, the process triggers dynamically: the standby switch assumes the active role almost immediately, with role changes designed to be non-disruptive to ongoing operations through mechanisms like Nonstop Forwarding (NSF) and Stateful Switchover (SSO). This ensures that control plane state is synchronized between active and standby switches prior to any transition.[44][52]Failover in StackWise environments is engineered for high availability, providing hitless transitions where the data plane remains operational during the switchover. When the active switch fails, the standby takes over the master role, leveraging NSF/SSO to maintain packet forwarding without interruption, achieving subsecond recovery times typically under 50 milliseconds in supported scenarios. Cisco Express Forwarding (CEF) plays a critical role by preserving forwarding tables and hardware adjacency entries across the transition, preventing traffic loss or reconvergence delays in the network. This mechanism supports seamless operation for protocols like routing and spanning tree, ensuring minimal impact on connected devices.[52][44]Recovery from stack changes, such as adding or removing members, is facilitated without requiring a full stack reboot, enhancing operational flexibility. New switches can be hot-added by connecting StackWise cables and powering on, with the stack automatically detecting and integrating the member while retaining the existing active switch; the stack may temporarily operate at half bandwidth until the full ring is restored. For removal, powering off the switch is recommended to avoid partitioning the stack, but the remaining members continue functioning cohesively. In cases of software version mismatches during addition, the auto-upgrade feature automatically provisions the compatible image from the active switch to the new member, allowing it to join without manual intervention, provided the versions are within the supported compatibility matrix. Auto-advise notifies administrators of incompatible versions if auto-upgrade is disabled.[52][44]
Product Models
Fixed-Configuration Switches
Fixed-configuration switches within the Cisco Catalyst portfolio are non-upgradable, all-in-one devices featuring integrated ports and application-specific integrated circuits (ASICs) for high-performance switching, without provisions for expansion slots or line cards. This design prioritizes simplicity, reliability, and reduced complexity in deployment, making them ideal for access and distribution layers where fixed port requirements predominate. They leverage Cisco IOS or IOS XE software for Layer 2 and limited Layer 3 functionality, supporting features like VLANs, QoS, and basic routing in a compact footprint.[47][79]Key examples illustrate the evolution of this form factor: the Catalyst 9200 series, launched in 2018, supports software-defined networking (SDN) and intent-based automation, maintaining the fixed port architecture while adding multigigabit options for modern Wi-Fi deployments. These models integrate dedicated ASICs, such as the Unified Access Data Plane (UADP), to handle wire-speed forwarding without the need for modular upgrades.[79][78]These switches excel in use cases such as branch offices and campus access layers, where they connect end-user devices like desktops, IP phones, and wireless access points. Power over Ethernet Plus (PoE+) support enables powering of connected devices with budgets up to 740W across ports, facilitating deployments in environments without dedicated power infrastructure. Stacking technologies, like StackWise-160 in the 9200 (up to 160 Gbps across 8 units), allow multiple switches to operate as a single logical unit for simplified management and redundancy.[79][80]Performance specifications highlight their efficiency in space-constrained settings, with representative models supporting up to 48 Gigabit Ethernet ports and switching capacities reaching 400 Gbps in a 1U rack-mountable chassis. For example, the Catalyst 9200-48PXG delivers 400 Gbps switching and a forwarding rate of 297.61 Mpps, suitable for high-density access without requiring chassis-based scalability. Compared to modular switches, fixed-configuration models provide easier initial setup and lower costs for predictable port needs but rely on stacking for expansion rather than slot-based upgrades.[79]The fixed-configuration lineup includes the active Catalyst 9000 series fixed variants, such as the 9200, 9200L, 9300, and 9300X (as of November 2025), emphasizing enterprise-grade features including Cisco DNA Center integration for automation, zero-touch provisioning, and enhanced security, delivering up to 256 Gbps switching in models optimized for branch and mid-sized campus networks. The 9300X variant, introduced for higher performance, supports advanced multigigabit Ethernet and increased stacking bandwidth.[78][11]
Modular Switches
Modular switches in the Cisco Catalyst lineup feature chassis-based architectures designed for high scalability and flexibility in enterprise environments. These switches utilize a modular design with dedicated slots for supervisor engines that handle control plane functions, line cards for portconnectivity, and redundant power supplies to ensure operational continuity. In more recent offerings, the Catalyst 9400 series provides chassis such as the C9404R (four slots), C9407R (seven slots), and C9410R (ten slots), each with two dedicated supervisor slots, while the Catalyst 9600 series features the C9606R chassis optimized for core deployments with full front accessibility (as of November 2025). Power supplies in these systems, such as the hot-swappable 3200W units in the 9400 series, support N+1 or N+N redundancy to minimize downtime.[43][81]Scalability is a core strength of these modular platforms, enabling expansion through interchangeable components without full system replacement. Modern series like the 9400 achieve up to 9 Tbps of system bandwidth and 384 ports, including multigigabit and 100G fiber options, with 480 Gbps per slot using high-end supervisors like the C9400X-SUP-2XL.[43] The Catalyst 9600 series pushes further to 25.6 Tbps switching capacity, accommodating 100G, 40G, and 25G ports in modular setups. Hot-swappable modules, including line cards, supervisors, fans, and power supplies, facilitate redundancy and maintenance without service interruption across all these series, enhancing reliability in demanding networks.[82][43]These modular Catalyst switches are primarily deployed in data centers and enterprise core/aggregation layers, where their ability to handle high traffic volumes and integrate advanced services is essential. For data centers, the 9400 and 9600 series provide SD-Access integration, automation, and high-density PoE for IoT and cloud environments, supporting up to four non-blocking 100G uplinks per supervisor.[43]Key series in the modular Catalyst portfolio include the 9000 family—encompassing 9400 and 9600—for contemporary core roles with Silicon One ASICs and enhanced analytics (as of November 2025). Port expansion is further enabled through technologies like StackWise Virtual in the 9400 series, allowing logical aggregation without traditional fabric extenders, though compatible extensions can increase density in aggregation scenarios.[43][11] This modularity contrasts with fixed-configuration models used in simpler branch deployments, offering greater adaptability for evolving network demands.[11]
Discontinued Products
End-of-Life Models
The Cisco Catalyst end-of-life (EOL) models represent earlier generations of switches that have been officially discontinued, marking the conclusion of new sales and eventual cessation of support services. These models played pivotal roles in enterprise networking but were phased out to make way for advanced architectures. Key examples include the Catalyst 2900 series, which reached end-of-sale in 2001 with support ending in 2006; the Catalyst 3560 series, with end-of-sale dates spanning 2012–2016 for various sub-models and support concluding by 2021; and the Catalyst 3850 series, which saw partial end-of-sale announcements starting in 2020 for select configurations, culminating in full end-of-sale by 2022, with support for copper models ending on October 31, 2025, and for fiber models ending on April 30, 2027.[83][84][85][86][87][88]Discontinuation of these models was driven by the need to transition to more capable platforms, such as the Catalyst 9000 series, which incorporate superior silicon for higher throughput and energy efficiency, enhanced security features like encrypted traffic analytics, and built-in automation capabilities for intent-based networking.[89] For instance, the Catalyst 3850's stackwise-480 technology and integrated wireless controller were superseded by the 9000 series' StackWise Virtual and DNA Center integration, offering greater scalability and simplified management.The impact of reaching EOL includes a defined period of post-sale support, typically 5–7 years, after which Cisco no longer provides software updates, hardware replacements, or vulnerability patches, potentially exposing networks to unmitigated security risks.[90] For the Catalyst 2900 series, this meant support ended five years after end-of-sale; the 3560 series followed a similar 5-year window, with end-of-support in 2018–2021; and the 3850 series extended to October 31, 2025, for copper models (now ended as of November 2025) and April 30, 2027, for fiber models, allowing time for upgrades but urging migration to avoid compliance issues in regulated environments.[83][91][92]Among the earliest Catalyst lines, the 5000 and 6000 series from the mid-1990s laid the groundwork for multilayer switching, introducing hardware-based Layer 3 forwarding that revolutionized enterprise LANs by combining routing intelligence with switch speed.[93] These chassis-based systems supported modular expansion and VLAN trunking, enabling scalable, high-performance networks foundational to modern Cisco switching paradigms. Migration from EOL models to current offerings like the Catalyst 9000 series is recommended to maintain security and performance.[89] Note that select configurations of the Catalyst 3560-X and 3750-X series had additional end-of-sale announcements in September 2023.[94][95]
Model Series
End-of-Sale Date
End-of-Support Date
Key Notes
Catalyst 2900 XL
October 31, 2001
November 1, 2006
Fixed-configuration Ethernet switches; replaced by 2950 series.[83]
Catalyst 3560
January 30, 2013 (select models); October 30, 2016 (3560-X)
January 30, 2018 (select); October 31, 2021 (3560-X)
Layer 3 access switches; enhanced PoE and IP services. Select configurations EOS September 5, 2023.[96][97][94]
Catalyst 3850
October 30, 2020 (partial); April 30, 2022 (full)
October 31, 2025 (copper models, ended); April 30, 2027 (fiber)
Stackable with wireless integration; partial phase-out for legacy SKUs.[87][92]
Legacy Support and Migration
Cisco provides structured support phases for legacy Catalyst switches, including extended warranty options, software maintenance releases, and Cisco Smart Net Total Care services, which offer 24/7 technical assistance, hardware replacement, and access to software updates for eligible models.[98] For older series such as the Catalyst 3750X, support ended on the Last Date of Support (LDOS) five years after End-of-Sale (EOS) on October 31, 2021.[99] Similarly, for the Catalyst 6500 Series Supervisor Engine 2T, service contracts were renewable until the end of the defined support period on October 31, 2025, after which the SNTC portal for these models was decommissioned.[100][101][102]The Cisco Technology Migration Program (TMP) facilitates transitions from legacy Catalyst models by offering trade-in credits toward newer switches and providing compatibility matrices to ensure seamless integration.[103] For instance, organizations migrating from Catalyst 6500/6800 series can leverage TMP incentives, which include assessments of existing hardware and recommendations for compatible upgrades, such as retaining certain line cards during supervisor replacements.[104] These tools help preserve investments while addressing obsolescence, with detailed matrices outlining supported firmware versions and hardware pairings for models like the Catalyst 2960-X.[105]Migrating legacy Catalyst switches presents challenges, particularly firmware limitations where End-of-Support models receive no further updates, increasing vulnerability to security threats and complicating compliance with regulations like GDPR.[106] Older hardware often requires full refreshes to meet modern encryption standards and dataprotection mandates, as legacy systems may lack features for auditing personally identifiable information (PII) processing, posing risks under GDPR's visibility and consent requirements.[107][108]Best practices for migration emphasize phased upgrades to minimize network disruption, utilizing StackWise technology to enable hot-swappable additions of new switches into existing stacks without downtime.[106] This approach involves staging firmware updates in install mode for Catalyst 9000 series stacks, where the active switch propagates consistent software versions to newly joined members, ensuring high availability during incremental rollouts.[109][52]
Current Offerings
Active Product Lines
The Cisco Catalyst 9000 family represents the core of active product lines for enterprise networking as of 2025, encompassing fixed and modular switches designed for modern campus, branch, and data center environments.[11] This family includes the 9200, 9300, 9400, 9500, 9600, and C9350 series, offering scalable performance with capacities reaching up to 25.6 Tbps in the high-end 9600 chassis and support for 5G connectivity through companion Cisco Catalyst Cellular Gateways.[11][110] All models run on Cisco IOS XE 17.x software, starting from version 17.18.1, which enables advanced programmability and automation.[111] Key shared features include AI-driven analytics via ThousandEyes integration for network visibility and zero-trust security models incorporating MACsec-256 encryption, TrustSec policy enforcement, and Encrypted Traffic Analytics (ETA).[11]The Catalyst 9200 series targets campus and branch deployments, providing fixed-configuration access switches suitable for small to medium-sized enterprises with stacking bandwidth up to 160 Gbps.[11] These models support enhanced Power over Ethernet (PoE) for IoT devices and include compact, fanless options like the C9200CX for wall-mount installations in space-constrained locations.[11]For aggregation roles in business-critical branch and campus networks, the Catalyst 9300 series delivers fixed enterprise access with up to 1 Tbps stacking bandwidth across eight chassis and support for modular uplinks.[11] It emphasizes security and cloudintegration, making it ideal for environments requiring high-density ports and AI/ML-based threat detection.[11]The Catalyst 9400 series serves modular access and aggregation needs in campus distribution layers, offering 480 Gbps per slot and up to 9 Tbps per chassis for flexible scaling.[11] Its design supports edge computing applications with zero-trust capabilities and integration with Cisco Spaces for location analytics.[11]High-performance core and aggregation are addressed by the Catalyst 9500 series, which uses the Silicon One Q200 ASIC for fixed 12 Tbps capacity in a 1 RU form factor, optimized for data center interconnects and low-latency operations.[11] Complementing this, the Catalyst 9600 series provides modular core switching with 6.4 Tbps per slot and 25.6 Tbps chassis capacity, targeting large-scale enterprise cores with advanced routing and multicast support.[11]Introduced in 2025, the Catalyst C9350 series consists of fixed smart switches for access layer deployments, built on Cisco Silicon One ASICs. These models deliver up to 10 Gbps multigigabit Ethernet ports, 90 W UPOE+ on every port, and are optimized for Wi-Fi 7 environments, providing enhanced security and automation for high-density workplaces.[112]Availability across the 9000 family includes rack-mountable chassis for standard deployments and wall-mount variants for the 9200 series, with pricing structured in tiers such as Cisco Catalyst Essentials for basic SMB needs and Advantage for enterprise-grade features like advanced analytics and security subscriptions.[11] These offerings are accessible through Cisco's global sales channels, ensuring broad deployment options.[11]
Recent Cisco Catalyst series, particularly the 9000 family, integrate advanced automation and artificial intelligence capabilities through Cisco Catalyst Center, enabling intent-based networking that automates policy enforcement and configuration across wired and wireless environments.[63] This platform leverages AI-driven diagnostics and remediation to optimize network performance, reducing manual interventions and improving operational efficiency.[63] Cisco DNA Assurance, now evolved into Catalyst Assurance, provides predictive analytics for capacity planning and proactive issue resolution, while incorporating anomaly detection to identify deviations in network behavior, such as unusual traffic patterns, before they impact users.[113] These features allow network administrators to gain real-time insights and automated responses, enhancing reliability in enterprise deployments.[11]Sustainability efforts in the latest Catalyst series emphasize energy-efficient hardware and materials to minimize environmental impact. The Catalyst 9000 switches feature platinum-rated power supplies and active power management, including reduced power modes for idle ports, which contribute to lower overall energy consumption compared to earlier generations.[114] In 2024, several models in this family achieved ENERGY STAR certification from the U.S. Environmental Protection Agency, recognizing their superior energy efficiency in large network equipment.[115] Additionally, Cisco incorporates circular design principles, using recyclable materials and modular components to facilitate easier upgrades and reduce e-waste, aligning with the company's goal of 100% circular design in new products by the end of fiscal 2025, which was achieved in October 2025.[116]Emerging technologies in recent Catalyst offerings support higher-speed connectivity and distributed computing at the network edge. While traditional Catalyst switches focus on campus and branch environments, integrations enable 400G capabilities through compatible optics and modules for aggregation scenarios, facilitating scalable data centeredge connectivity.[117] Wi-Fi 7 convergence is advanced via the Catalyst 9100 access points and 9800 controllers, which combine multi-link operations across 2.4 GHz, 5 GHz, and 6 GHz bands with wired Catalyst infrastructure for seamless, high-density wireless experiences supporting up to 40 Gbps throughput.[118] For edge computing, the Catalyst 9000 series hosts Docker containers natively via IOx, allowing third-party applications to run directly on the switch for low-latency processing without external servers, ideal for IoT and analytics workloads.[119]Quantum-safe encryption is being embedded via post-quantum cryptography in IOS XE software, including support for algorithms like ML-KEM (as of 2025), utilizing preshared keys to protect against quantum threats across Catalyst switches.[120] These advancements position the series to address evolving security and performance demands in next-generation networks.[121]