SW005F 5-Port Switch

Today, let’s talk about switch selection, a common issue that both new and experienced network engineers often encounter. Many newcomers tend to get confused.

Of course, there are many important technical parameters to consider when selecting a switch. These include hardware specifications such as 100/1000/10000 Mbps port speeds, electrical/optical/PoE ports, number of ports, MAC address table depth, forwarding delay, buffer size, VLAN support, and isolation.

From a network hierarchy perspective, the requirements for each layer are different. Access layer, aggregation layer, or core layer switches have different requirements. You also need to consider fixed configuration, modular, or stackable switches.

Many projects suffer from various issues due to improper switch selection, seriously affecting project delivery and user experience.

Today, I will share some key points to consider when selecting switches.

However, in real projects, as a salesperson or pre-sales engineer, you must first consider the switch price and the client’s budget.

Not discussing budget in switch selection is just playing tricks, right?

01 Evaluating Basic Requirements

01 Determining Network Scale and Application

Before selecting a switch, you need to clarify the scale of the network and the expected application scenarios.

• Network Topology: Understand whether your network uses a star, ring, or other specific topology.
• Number of Users: Estimate the number of devices connected to the network, including computers, servers, printers, etc.
• Traffic Prediction: Consider the daily network traffic demand, especially the data transmission volume during peak hours.

02 Performance Indicators

• Throughput: Measures the switch’s data processing capability, usually in Mbps (million bits per second) or Gbps (billion bits per second).
• Backplane Bandwidth: The maximum internal data transfer capacity of the switch, determining the switch’s maximum theoretical throughput.
• Latency: The time required for a data packet to travel from the source port to the destination port, the lower the better.

03 Additional Features and Requirements

• VLAN Support: Virtual LAN segmentation can enhance network security and management efficiency.
• QoS (Quality of Service): Ensures priority and bandwidth allocation for critical applications.
• Redundancy Design: For example, dual power supplies and hot-swappable modules, to improve system reliability and availability.

04 Security Features

• Access Control Lists (ACLs): Restrict access for specific IP addresses or MAC addresses.
• Port Security: Prevents unauthorized devices from accessing the network.
• Encryption: Supports security protocols such as SSL/TLS to protect data transmission security.

02 Choosing Between Gigabit and 100 Mbps?

01 Differences Between Gigabit and 100 Mbps

When selecting a switch, the first decision is whether to use a Gigabit (1 Gbps) or 100 Mbps interface. The main differences between these interfaces lie in speed and application scenarios.

• Speed Comparison:
  • 100 Mbps: Provides a maximum data transfer rate of 100 Mbps, suitable for small networks or environments with low bandwidth requirements.
  • Gigabit: Provides a maximum data transfer rate of 1 Gbps, suitable for medium to large networks or environments requiring high-speed data transfer.
• Application Scenario Analysis:
  • 100 Mbps Switches: Suitable for home networks, small offices, or scenarios with low traffic demand.
  • Gigabit Switches: More suitable for enterprise-level networks, data centers, or applications requiring large amounts of data transfer.

02 Consideration Factors

• Analyze Current Network Traffic: Analyze the current network traffic situation and predict growth trends over the next few years.
• Future Expansion: If traffic is expected to increase significantly, it is recommended to choose a Gigabit switch to meet future expansion needs.
• Cost Consideration: Gigabit switches are generally more expensive than 100 Mbps switches.
• Cost-Benefit Analysis: Weigh whether the additional investment is worthwhile, especially in cases where current network traffic is low.

03 Practical Case Analysis

• Small Office:
  • Network Scale: Small, with few connected devices.
  • Main Uses: File sharing, printing, and basic internet access.
  • Recommendation: Choose a 100 Mbps switch.
• School or Hospital Network:
  • Network Scale: Larger, requiring high bandwidth applications such as multimedia file transfer and video conferencing.
  • Recommendation: Choose a Gigabit switch.
• Enterprise Data Center:
  • Main Uses: Requires handling large amounts of data exchange, such as database synchronization and large-scale file transfer.
  • Recommendation: Choose a Gigabit switch and consider products with higher port density and redundancy design.

04 Summary and Recommendations

• Low Traffic: If network traffic is relatively small and there is no significant growth trend, a 100 Mbps switch is an economical choice.
• High Traffic: For scenarios requiring large amounts of data transfer or with a significant traffic growth trend, it is recommended to choose a Gigabit switch to ensure network performance and stability.

03 How to Choose a Core Switch?

The core switch, as the heart of the network, is responsible for high-speed packet forwarding and needs to have high reliability and scalability.

01 Characteristics of Core Switches

Core switches have some significant characteristics compared to other types of switches:

• High Performance and Reliability: Core switches typically have higher data processing capabilities, capable of quickly forwarding large amounts of packets, and support redundancy features such as dual power supplies.
• Multi-Layer Support: Supports Layer 3 (network layer) and even higher-layer routing functions, enabling more complex network policies and traffic management.
• Scalability: Supports modular architecture, allowing for easy upgrades as the network grows by adding different interface modules as needed.

02 Selection Guide

• Modular Expansion: Confirm whether the core switch supports modular expansion to easily upgrade as the network scales. Check if there are enough slots to accommodate additional interface modules.
• Redundancy: Check if the core switch supports redundant power supplies to prevent network outages due to a single power failure. Confirm if there is support for hot-swappable modules to replace faulty components without shutting down the system.
• Management Interface: Ensure the core switch has a robust management interface, supporting SNMP, Web GUI, and other management methods. Check if it supports remote management for convenient monitoring and configuration when physically distant from the core switch.
• Advanced Security Features: Confirm if the core switch supports advanced security features such as ACLs and firewall functions. Check if there are built-in DDoS protection measures to defend against potential network attacks.

In addition, in typical large monitoring networks, traffic is not concentrated on a single port but distributed across multiple ports, forwarded by multiple Gigabit ports, as shown in the diagram.

It can be seen that none of the ports exceed 1000M, and any two Gigabit ports on a full Gigabit switch can achieve 1000M bidirectional transmission. The total throughput (full load) is generally less than or equal to the switch’s backplane bandwidth.

Therefore, when selecting a core switch, based on the number of IPCs, the recommendations are as follows:

• Less than 50 IPCs:
  • Demand Analysis: For small-scale deployments, a very high-end core switch may not be necessary.
  • Recommended Configuration: Choose a switch with at least 24 Gigabit ports.
  • Features: Supports simple QoS and VLAN segmentation.
  • Considerations: Consider models with redundant power options to improve reliability.
  • Note: Ensure the switch has enough ports to support all IPCs and necessary network devices (such as routers, firewalls, etc.). Consider future expansion needs.
• 50 to 200 IPCs:
  • Demand Analysis: As the number of IPCs increases, the requirements for the core switch also increase.
  • Recommended Configuration: Choose a switch with 48 Gigabit ports or higher density, considering SFP+ ports for fiber connections.
  • Features: Supports Layer 3 routing functions to optimize network performance.
  • Considerations: Should have redundant power and hot-swappable module support.
  • Note: Ensure the switch’s backplane bandwidth is large enough to support the high bandwidth demands of all connected devices. Consider the network’s complexity and choose an easy-to-manage and monitor switch.
• Over 200 IPCs:
  • Demand Analysis: For large deployments, the core switch must have extremely high performance and reliability.
  • Recommended Configuration: Choose a switch with high-density Gigabit or 10 Gigabit ports or Layer 3 switches, supporting modular expansion.
  • Features: Supports advanced QoS and security features such as ACLs and firewall functions.
  • Considerations: Must have redundant power, hot-swappable modules, and advanced failover mechanisms.
  • Note: Evaluate the overall network traffic and bandwidth demand to ensure the core switch can handle these loads. Consider using a distributed core architecture to distribute the load across multiple core switches.

04 How to Choose a PoE Switch?

PoE (Power over Ethernet) switches can power connected devices while transmitting data, which is particularly useful for deploying network cameras (IPCs), wireless access points, IP phones, and other devices.

01 Advantages of PoE Switches

• Simplified Cabling: Only one Ethernet cable is needed to transmit data and power, reducing the need for separate power lines.
• Reduced Installation Costs: No additional power outlets are needed, reducing overall installation costs.
• Flexibility: Devices can be deployed in locations difficult to access with power, increasing installation flexibility.

02 Selection Points

• PoE Standards:
  • 802.3af (PoE): Provides up to 15.4W of power.
  • 802.3at (PoE+): Provides up to 30W of power.
  • Choose the appropriate PoE standard based on the power consumption of the connected devices.
• Power Budget:
  • Calculate the total power demand of all connected devices and ensure the PoE switch’s total power budget exceeds this value.
  • Consider future device additions and reserve some power margin.
• Compatibility:
  • Confirm the PoE switch is compatible with the devices you plan to connect.
  • Check if the devices support the correct PoE standard.
• Number and Type of Ports:
  • Determine the required number of PoE ports.
  • Consider whether non-PoE ports are needed for other device connections.
  • Consider whether SFP ports are needed for fiber connections.

03 Practical Case Analysis

• Small Office:
  • Device Requirements: 8 IP phones, 6 wireless access points.
  • Recommended Choice: 16-port PoE switch, with at least 10 PoE ports supporting the 802.3af standard.
  • Features: Cost-effective, easy to install and manage.
• Large Retail Store:
  • Device Requirements: 20 network cameras, 10 wireless access points.
  • Recommended Choice: 24-port PoE+ switch, all ports supporting the 802.3at standard.
  • Features: High power budget, supports high-power devices.

05 How to Choose a Fiber Switch?

Fiber switches use fiber optic cables for data transmission, providing higher bandwidth and longer distance transmission capabilities than traditional copper cables.

01 Necessity of Fiber Switches

• Long Distance Transmission: Fiber can support distances from hundreds of meters to several kilometers, suitable for network connections across buildings or geographical regions.
• High-Speed Data Transmission: Fiber switches support high-speed transmission, such as 10Gbps, 40Gbps, or higher rates, suitable for data centers and high-performance computing environments.

02 Selection Considerations

• SFP/SFP+ Module Support:
  • SFP: Suitable for 1Gbps fiber connections.
  • SFP+: Suitable for 10Gbps fiber connections.
  • Ensure the switch supports the required SFP/SFP+ module types.
• Fiber Interface Types:
  • LC/SC/ST/MTRJ: Understand which type of fiber connector your network devices support.
  • Choose an interface type compatible with existing devices.
• Transmission Distance and Bandwidth Requirements:
  • Select the appropriate transmission distance (short, medium, long) based on actual network needs.
  • Determine the required minimum bandwidth, such as 1Gbps, 10Gbps, etc.
• Redundancy Design:
  • Consider designs supporting redundant power supplies and hot-swappable modules to improve network reliability and availability.
  • Check if there are spare fiber ports to support network redundancy connections.
• Scalability:
  • Choose fiber switches supporting modular expansion to easily expand network scale in the future.

03 Practical Case Analysis

• Enterprise Data Center:
  • Requirements: Need to support high-speed data transmission between multiple server racks.
  • Recommended Choice: Fiber switch supporting SFP+ ports, with at least 10Gbps speed.
  • Features: High bandwidth, low latency, suitable for high-performance computing environments.
• Campus Network:
  • Requirements: Need to connect multiple buildings across long distances.
  • Recommended Choice: Fiber switch supporting long-distance transmission, with LC or SC interfaces.
  • Features: Long-distance transmission capability, supports high bandwidth demands.