Guide to Ethernet Switches and Cabling Basics

What is an Ethernet Switch Class?

An Ethernet switch class defines the role and capabilities of a network device within a structured network design. It helps determine how well the switch fits into various parts of your infrastructure—from simple access points to core backbones.

Key Characteristics:

• Forwarding Type: Layer 2 (MAC-based) or Layer 3 (IP-routing)
• Scalability: How it scales up as network grows
• Redundancy: Features preventing single-point failures
• Performance: Data transfer speeds and reliability
• Management: Tools available for monitoring and troubleshooting

RJ45 Connector Types

RJ45 connectors are commonly used for wired Ethernet connections. There are two main pinout schemes:

1. Straight-through cable: Connects similar devices (PC to PC, router to router). Uses standard pinouts where wire colors match on both ends.
2. Crossed-over cable: For connecting dissimilar devices (switch to hub, router to modem). Wire colors cross at pins 1, 2, 3, and 6.

Correctly crimping cables ensures reliable signal transmission and prevents issues like interference or poor connection quality.

Categories of Twisted Pair Cable

Twisted pair cables come in categories defined by IEEE standards, specifying bandwidth and maximum supported data rate. Here's what they mean:

• Category 5e (Cat5e): Maximum frequency 100 MHz, supports Gigabit Ethernet (up to 1Gbps). Commonly used in residential and small office installations.
• Category 6 (Cat6): Maximum frequency 250 MHz, supports up to 10Gbps over short distances (~55 meters). Enhanced shielding reduces crosstalk.
• Category 6a (Cat6a): Maximum frequency 500 MHz, supports longer runs of 10Gbps (~100 meters). Heavier gauge wires improve performance further.
• Category 7 (Cat7): Shielded cable supporting frequencies beyond 600MHz, capable of 10Gbps over long distances. Primarily used in professional settings requiring very high speeds.

Types of Ethernet Switches

1. Layer 2 Access Switches

+ Easy installation & maintenance
+ Affordable price point
+ Ideal for small business networks
- Limited scalability
- No advanced routing capabilities
Functions: MAC address learning, forwarding decisions based on layer 2 addresses
Popular models: Cisco Catalyst 2960, HPE Procurve 2510, MikroTik CRS125-24G-1S+
            

2. Layer 3 Distribution Switches

+ Advanced routing functionality
+ High performance
+ Scalability for mid-to-large enterprise networks
- More complex setup and management
- Higher cost compared to layer 2 switches
Functions: Routing protocols support (OSPF, EIGRP), VLAN aggregation, QoS policies
Popular models: Cisco Catalyst 3850, HPE Altoline 8600, Juniper EX4300
            

3. Core Layer Switches

+ Extreme throughput capacity
+ Low latency
+ Reliability and redundancy
- Expensive investment
- Complex configurations required
Functions: Load balancing, multicast routing, advanced security features
Popular models: Cisco Nexus 9000 series, Arista Networks 7500E, Brocade MLXe Core Router
            

4. Edge Switches

+ Connectivity optimization for branch offices
+ WAN link aggregation
+ Security features for remote sites
- Less powerful than core/distribution switches
- Costlier per port
Functions: VPN termination, firewall integration, load balancing
Popular models: Cisco ISR 4451, Fortinet FortiGate 60E, Juniper SRX240
            

5. Data Center Fabric Switches

+ Super-fast interconnection between server racks
+ Scalable architecture
+ Reduced latency and congestion
- Designed specifically for cloud/datacenter environments
- Requires specific expertise to deploy
Functions: Leaf-spine topology support, unified fabric solutions
Popular models: Cisco Nexus 9300 series, Mellanox SN2700, Brocade SLX 9850
            

6. WAN Edge Gateways

+ Connection to external service providers/WAN links
+ Supports MPLS, GRE tunnels, IPsec VPNs
+ Optimized for distributed enterprises
- Often requires specialized knowledge to configure
- May not offer full feature set found in core switches
Functions: Dynamic routing, multi-WAN capability, integrated firewalls
Popular models: Cisco ASR 1000 series, Juniper MX series, Huawei NE40E-X8A
            

7. Managed Stackable Switches

+ Centralized management through stacking technology
+ Scales easily by adding more units
+ Improved uptime due to redundant paths
- Need proper planning before deployment
- Initial cost may seem higher
Functions: Link Aggregation Control Protocol (LACP), Port Mirroring, PoE power distribution
Popular models: Cisco SG350 series, NETGEAR XS708E, Ubiquiti UniFi Switch XG
            

8. Unmanaged Switches

+ Plug-and-play simplicity
+ Very affordable pricing
+ Suitable for home users or SOHO environments
- Lack advanced networking features
- Limited expansion possibilities
Functions: Fixed configuration, limited diagnostic tools
Popular models: TP-Link TL-SG1008D, Netgear FS108, D-Link DES-1005D