Introduction

As organizations work to stay ahead in the digital age, businesses often find themselves at a crossroads, considering upgrading their systems to meet the demands of modern connectivity. One such problem revolves around the decision to migrate Cisco Catalyst 6500 series switches to the more advanced Cisco Nexus 9000 switches.

The new Cisco Nexus 9000 Series Switches offer data center-specific features such as high 10 and 40-Gbps port densities, reliability, performance, scalability, programmability, and ease of management. The Cisco Nexus 9000 Series provides versatile platforms that can be deployed in a variety of scenarios, including layered access-aggregation-core designs, leaf-and-spine architecture, and compact aggregation solutions.

Organizations must understand the implications of these changes on current business services and applications as new business services and applications emerge, prompting enterprises to seek new data center infrastructure designs. Layer 2 mobility, bandwidth and latency, and symmetrical paths through load balancers and firewalls must all be carefully considered to ensure the successful migration of business services from your current data center infrastructure to your new one.

Purpose of this Guide

This article explores the complexities and key considerations, benefits, and overall impact to assist network planners, engineers, and managers who are deploying Cisco Nexus 9000 Series Switches as replacements for Cisco Catalyst 6500 Series Switches in a data center.

Understanding the Cisco Catalyst 6500 Switches

Before comparing the two switch series, let's learn about the switches first. The journey begins with an overview of the Cisco Catalyst 6500 series switches. They've been super reliable and strong, helping lots of businesses connect their computers and devices. These switches are designed in a way that makes them connect their computers and devices. However, as technology has advanced, businesses need to decide if these trusty switches are still the best fit or if they should upgrade to something brand new, like the Cisco Nexus 9000.

Overview of Cisco Nexus 9000 switches

Cisco Nexus 9000 switches are like superheroes for computer networks. Imagine them as super-fast traffic controllers for information travelling through the internet. These data center switches are designed to handle a lot of information quickly and adapt to new technologies. Unlike the c6500, these Nexus 9000 switches come with cool features like VXLAN and ACI, making them stronger. These switches are not just faster; they're smarter too. So, if you want a network that's not just reliable but also ready for the future, the Cisco Nexus 9000 switches are your go-to heroes!

Features of Cisco Catalyst 6500 Series Switches

Reliability: The Cisco Catalyst 6500 series is known for its robust and stable performance, providing a reliable foundation for network infrastructure.

Scalability: These switches offer moderate scalability, suitable for medium-sized networks, but may face limitations when dealing with the demands of larger enterprises.

Legacy Technology: As a part of Cisco's older generation, the Catalyst 6500 series relies on traditional technology, lacking some of the advanced features found in newer models.

Configuration Complexity: Setting up and configuring Catalyst 6500 switches can be intricate, requiring a certain level of expertise to optimize their functionality.

Limited Programmability: The switches have limitations in terms of programmability, hindering adaptability to rapidly changing network requirements.

Features of Cisco Nexus 9000 Series Switches

Advanced Features: Cisco Nexus 9000 switches are equipped with cutting-edge features like VXLAN (Virtual Extensible LAN) and ACI (Application Centric Infrastructure), enhancing network capabilities.

High Scalability: Designed for modern data centers, Nexus 9000 switches offer superior scalability, accommodating the high data loads and complexities of today's networks.

Future-Ready Technology: These switches leverage innovative technology, making them more adaptable to emerging trends and ensuring long-term viability for businesses.

Simplified Configuration: Cisco Nexus 9000 switches prioritize user-friendly configurations, streamlining the setup process and making them more accessible to a broader range of users.

Enhanced Programmability: With a focus on automation and programmability, Nexus

9000 switches provide greater flexibility, allowing businesses to respond dynamically to evolving network needs.

Benefits of Catalyst 6500 switches and Nexus 9000

Table 1 lists some benefits and compares both switch series.

Feature	Cisco Catalyst 6500	Cisco Nexus 9000
Purpose	Core and Distribution Switching	Data Center Switching
Modularity	Highly modular with various line cards and modules	Modular design with fixed or modular line cards
Forwarding Architecture	Centralized forwarding (Supervisor Engine)	Distributed forwarding (Leaf-Spine Architecture)
Throughput	High throughput with fabric-enabled modules	High throughput with low-latency forwarding
Port Density	Offers a variety of port densities	High port density with options for 1/10/25/40/100G
Virtualization Support	Supports VLANs and VRFs for network segmentation	VXLAN support for network virtualization
Software Defined Networking	Limited SDN capabilities	Strong support for SDN through ACI (Application Centric Infrastructure)
Multicast Support	Robust multicast features	Enhanced multicast support
QoS (Quality of Service)	Comprehensive QoS features	Advanced QoS capabilities
Management	Traditional CLI and SNMP management	Enhanced management with NX-OS and RESTful APIs
Security Features	Integrated security features like ACLs and firewalls	Advanced security features with TrustSec and ACLs
Data Center Interconnect	Limited capabilities for DCI	Designed for efficient Data Center Interconnect
Power Efficiency	Consumes more power due to modular design	Energy-efficient design with lower power consumption
Ease of Upgrade	Modular design allows for easy upgrades	Firmware upgrades without service disruption
Compatibility	Extensive compatibility with various modules	Compatibility with Nexus line cards and modules

Switch Models and Configurations

The different switch models and configurations of Cisco Catalyst 6500 series switches and Cisco Nexus 9000 are listed in Table 2 below.

Feature	Cisco 6500 Series	Cisco Nexus 9000 Series
Product Line	Catalyst 6500 Series	Nexus 9000 Series
Architecture	Legacy (Supervisor and line cards)	Modern (Leaf-Spine architecture)
Switch Models	Various chassis options (6513, 6509, etc.)	Fixed (C9k-C9504, C9k-C9508) and modular (C9k-C93180YC)
Port Density	High port density with various line card options	High port density with fixed and modular options
Speed Options	Gigabit, 10 Gigabit, 40 Gigabit, 100 Gigabit	10 Gigabit, 25 Gigabit, 40 Gigabit, 100 Gigabit
Supervisor Engines	Various Supervisor engines (e.g., Supervisor 2T)	Nexus 9000 Supervisor Modules (e.g., N9K-SUP-A)
Modular Line Cards	Yes, supporting various interfaces and speeds	Yes, supporting various interfaces and speeds
Fabric Modules	Yes, for backplane connectivity	Yes, for spine-leaf fabric architecture
Software Platform	Cisco IOS (for older models), Cisco IOS XE	Cisco NX-OS
Virtualization Support	Limited virtualization support (VSS)	Full virtualization support (VXLAN, ACI)
Automation and Programmability	Limited programmability and automation capabilities	Enhanced programmability with support for APIs
Data Center Integration	Commonly used in traditional data center environments	Designed for modern data center and cloud environments
Use Cases	Core and distribution layer in enterprise networks	Data center, cloud, and spine-leaf deployments
EOL and Support Status	Some models may be End-of-Life (EOL) or nearing EOL	Active support for current models, check Cisco's site

Data Center Facilities

The availability of servers with 10-Gbps LAN-on-motherboard (LoM) technology is increasing the demand for high-density 10GBASE-T ports on access-layer switches. Most data centers with 10BASE-T cabling can save money by planning to upgrade their servers and access switches while maintaining their physical deployment models. Cisco Catalyst 6500 Series switches connect servers with 1-Gbps network interface cards (NICs) to the EoR or MoR.

Table 3 compares the platform form factors of the Cisco 6500 and Nexus 9000.

Feature	Cisco 6500	Nexus 9000
Form Factor	Modular chassis-based system	Fixed or modular chassis-based system
Chassis Sizes	Various chassis sizes available, e.g., 3-slot, 6-slot, 9-slot	Fixed chassis with different port options or modular chassis with various slot capacities
Port Density	High port density in larger chassis versions	High port density in both fixed and modular models
Architecture	Traditional switch architecture with separate supervisor and line cards	Cisco Nexus switch architecture with integrated supervisor and line cards
Scalability	Scalable with the ability to add more line cards and modules	Highly scalable with options for adding line cards or expansion modules
Purpose	Core and distribution layer switching	Designed for data center and enterprise cloud environments
Switching Capacity	Supports high switching capacity, suitable for large networks	High-capacity switching with low-latency for data center applications
Fabric and Backplane	Shared bus architecture with centralized switching fabric	High-speed non-blocking fabric and backplane architecture
Forwarding Paradigm	Traditional store-and-forward switching	Cut-through switching with low-latency forwarding
Port Speeds	Supports various port speeds, including Fast Ethernet, Gigabit Ethernet, and 10 Gigabit Ethernet	Provides support for 1/10/25/40/100 Gigabit Ethernet speeds
Software Compatibility	Runs Cisco IOS Software	Runs Cisco NX-OS Software
Virtualization	Limited virtualization capabilities	Advanced virtualization features, including VXLAN and Cisco ACI
Power Efficiency	Generally consumes more power compared to newer platforms	Designed for better power efficiency with energy-efficient components
Cooling	Requires substantial cooling infrastructure	Enhanced cooling efficiency with front-to-back or back-to-front airflow options
Maintenance and Upgrades	Modular design allows for easier maintenance and upgrades	Easier maintenance and upgrades with hot-swappable components and modular design

Modular Uplinks

Table 4 lists the modular uplinks of both switch series.

Feature	Cisco Catalyst 6500	Cisco Nexus 9000
Uplink Module Options	Various line cards with Gigabit Ethernet, 10 Gigabit Ethernet, 40 Gigabit Ethernet, and 100 Gigabit Ethernet options.	Fixed and modular options available, supporting 1/10/25/40/50/100 Gigabit Ethernet.
Modularity	Modular design with interchangeable line cards for flexibility and scalability.	Modular design for flexibility, allowing hot-swappable uplink modules.
Compatibility	Backward compatibility with some older line cards, providing investment protection.	Designed for modern data center environments, emphasizing current and future technologies.
Port Density	Scalable port density depending on the selected line cards.	High port density with a variety of fixed and modular options, suitable for various deployments.
Speed Options	Supports a range of speeds including 1G, 10G, 40G, and 100G.	Supports a wide range of speeds, including 1G, 10G, 25G, 40G, 50G, and 100G.
Uplink Protocols	Commonly supports protocols like Ethernet, IEEE 802.1Q VLANs, and others.	Supports modern protocols and standards, including VXLAN, EVPN, and Cisco's ACI.
Fabric Connectivity	Connected to the switch fabric through a high-speed backplane.	Utilizes a high-speed fabric with low-latency connectivity between components.
Redundancy and Resilience	Redundant supervisor modules for high availability.	Built-in redundancy features and support for high-availability configurations.
Scalability	Scales well for large enterprise networks with various expansion options.	Designed for scalability in modern data centers, accommodating evolving business needs.
Management and Automation	Management through Cisco IOS Software.	Management through Cisco NX-OS Software, offering automation capabilities.

Cisco Data Center Switches: A Comparative Study

The Role of Switches in Data Centers

Data centers are the nerve centers of modern businesses, requiring switches capable of dealing with the complexities of virtualization, cloud integration, and increasing workloads. The Cisco Nexus 9000 series is purposely built for these challenges, laying the groundwork for a strong and future-ready data center.

How Cisco Nexus 9000 Enhances Data Center Capabilities

The Nexus 9000 series, with features such as Application Centric Infrastructure (ACI) and improved automation, transforms data centers into agile, responsive, and efficient entities. Businesses that use these switches gain a competitive advantage in today's rapidly changing digital landscape.

Specifications

Switch Performance

Table 5 summarizes the switch performance specifications of both c6500 and Nexus 9000 switches.

Specification	Cisco Catalyst 6500 Series	Cisco Nexus 9000 Series
Switching Capacity	Up to 720 Gbps (per slot)	Up to 25.6 Tbps (fixed chassis)
Forwarding Rate	Up to 720 Mpps (per slot)	Up to 3 BPPs (fixed chassis)
Number of Slots	Up to 13 slots	Varies by model (e.g., 36, 48)
Maximum 10G Ports	Up to 384 ports	Up to 288 ports
Maximum 40G Ports	Up to 192 ports	Up to 96 ports
Maximum 100G Ports	Up to 72 ports	Up to 48 ports
Fabric Architecture	Centralized crossbar fabric	Scalable switch fabric with leaf-spine architecture
Modular or Fixed Chassis	Modular	Fixed
Virtualization Support	VSS (Virtual Switching System) for virtualization	Cisco ACI (Application Centric Infrastructure) for policy-based automation and virtualization
Latency	Sub-microsecond	Sub-microsecond
Power Supplies	AC and DC options	AC and DC options
Operating System	Cisco IOS	Cisco NX-OS