A switch is a network device operating at the Data Link Layer (Layer 2) of the OSI reference model. It is primarily used to forward data frames between devices within a local area network (LAN). Unlike a router, a switch focuses on data exchange within a LAN and utilizes a MAC address table to accurately route data packets to the intended device, preventing broadcast storms and improving network efficiency.
The operating principle of a switch can be summarized as "learn, forward, and filter." When a device sends data, the switch records the source MAC address and forwards the data to the appropriate port based on the destination MAC address. If the destination address is not in the MAC address table, the switch broadcasts the data to all ports except the sending port until the intended device is found.
Both non-PoE and PoE switches are based on this basic principle, but PoE switches have power supply capabilities in addition to basic switching functions, giving them an advantage in certain scenarios.
1. Overview of Non-PoE Switches
Non-PoE switches are the most basic type of switch and are primarily responsible for forwarding network data. Connect various devices, such as computers, printers, and servers, via Ethernet ports and efficiently transfer data based on MAC addresses.
Key features of non-PoE switches include:
Data forwarding: Forward data packets from one port to another based on the MAC address table.
VLAN support: Uses virtual local area network (VLAN) technology to separate network traffic, improving security and management efficiency.
Bandwidth management: Supports ports with different speeds (10/100/1000Mbps, and even 10Gbps) to meet the needs of various devices.
Management features: Some advanced non-PoE switches support management functions such as port mirroring, traffic monitoring, and QoS (Quality of Service) control.
Non-PoE switches can be divided into unmanaged and managed types. Unmanaged switches are plug-and-play and suitable for small network environments such as homes and small offices. Managed switches offer more detailed configuration options and are suitable for enterprises and complex network environments.
2. Advantages of Non-PoE Switches
Low Cost: Non-PoE switches, especially unmanaged switches, are relatively inexpensive, making them suitable for budget-conscious scenarios.
Easy Deployment: No complex configuration is required, allowing for quick network construction.
Versatile: Applicable to most network environments, from homes to businesses.
High Performance: Supports high-speed data transmission, meeting the bandwidth demands of modern networks.
3. Limitations of Non-PoE Switches
The main limitation of non-PoE switches is that they only provide data transmission functionality and are unable to supply power to devices. When powering network devices such as IP cameras and wireless access points, non-PoE switches require the use of additional power adapters or power supplies, increasing wiring complexity and cost. Furthermore, certain specialized scenarios may require additional management functions. Without these features, it can be difficult to meet complex network requirements.
4. Introduction to PoE Switches
PoE switches are devices that integrate Power Over Ethernet (PoE) technology based on standard non-PoE switches. It simultaneously transmits data and power over a standard Ethernet cable (such as Cat5e or Cat6) to power devices that support the PoE protocol, such as IP phones, surveillance cameras, and wireless access points. At its core, PoE technology utilizes unused wire pairs or data wire pairs within an Ethernet cable to transmit direct current, eliminating the need for an additional power cord.
PoE switches operate based on standards such as IEEE 802.3af, 802.3at, and 802.3bt.
IEEE 802.3af: Provides up to 15.4W of power, suitable for low-power devices like IP phones.
IEEE 802.3at (PoE+): Provides up to 30W of power, suitable for medium-power devices like high-resolution cameras and wireless access points.
IEEE 802.3bt (PoE++): Supports higher power levels (up to 90W), suitable for high-power devices like LED lighting and PTZ cameras.
When supplying power, a PoE switch first detects whether the powered device (PD) supports the PoE protocol via the power sourcing equipment (PSE), ensuring safe power delivery. Only if a compatible device is detected, the switch transmits power over the Ethernet cable, preventing damage to non-PoE-compatible devices.
Baudcom's 8-port PoE switch (Model: BD-S1010FSP) embodies this technology, with eight 10/100Mbps PoE ports that support the IEEE 802.3af/at standard, providing a PoE budget of up to 30W per port and a total of 120W. This switch also features two 10/100Mbps uplink RJ45 ports for flexible network connections.
5. Advantages of PoE Switches
· Simplified wiring: Simultaneous data transmission and power supply
necessarily through a single Ethernet cable, eliminating the need for additional power cords and reducing wiring costs and complexity.
· Flexible Deployment: PoE Switches can be installed in areas without power outlets, such as ceilings or outdoor locations, making them suitable for surveillance and wireless network scenarios.
· Centralized Management: PoE Switches typically support remote power management, allowing software control of power switches for devices, which improves maintenance efficiency.
· High Security: PoE Switches feature built-in overload protection and short-circuit protection mechanisms to ensure safe power supply.
6. Limitations of PoE Switch
Although PoE Switches are powerful, they also have some limitations:
· Higher Cost: The price of PoE Switches is usually higher than Non-PoE Switches, especially for models supporting high-power standards.
· Power Consumption Limits: The power supplied to each port is limited by PoE standards, and some high-power devices may require dedicated power sources.
· Compatibility Issues: Not all devices support the PoE protocol; Non-PoE devices require additional PoE splitters or adapters.
· Heat Dissipation Needs: PoE Switches generate more heat during power delivery and require good heat dissipation designs or fan support.