Network Bridge vs Switch: What are Their Differences

Network bridge vs switch, how much do you know about them? When it comes to networking devices, two commonly used terms that often arise are network bridges and switches. Understanding the distinctions between these two devices is crucial for effectively designing and managing network infrastructures. Let's delve deeper into the characteristics and functionalities of network bridges and switches to enhance our knowledge.

What is a network bridge?

A network bridge, also known as a bridge, is a storage and forwarding device that connects two local area networks (LANs). It allows the connection of network systems with identical or similar architectures, expanding the network's distance or coverage. By doing so, bridges not only extend the network's reach but also enhance its performance, reliability, and security. Operating at the data link layer, bridges establish connections between two LANs and forward frames based on MAC addresses. In a sense, bridges can be viewed as "lower-level routers" (routers operate at the network layer and forward based on network addresses such as IP addresses).

What is a switch?

Switches are the primary networking devices used for connecting devices in a network. Most switches operate at the data link layer (Layer 2) of the OSI reference model.

If we consider hubs as internal Ethernet buses, switches can be seen as a matrix of interconnected buses. Each switch port corresponds to a backplane bus with the bandwidth that is one order of magnitude higher (Core Bus), which is connected to a switch engine. Data packets between different ports are forwarded through the backplane bus and enter the switch engine, where they are switched using store-and-forward, cut-through, or fragment-free forwarding modes.

Network bridge vs switch: what are the differences?

The basic functions of a LAN switch are similar to those of a bridge, including frame forwarding, frame filtering, and spanning tree algorithm capabilities. However, there are several differences between switches and bridges:

1. Multiple Port Channels: Unlike bridges, switches allow multiple groups of ports to operate simultaneously. This means that a switch combines the functionalities of multiple bridges rather than just acting as a single bridge. While bridges typically have two ports, switches offer a high density of ports.

2. Segmentation Capability: Switches have the ability to segment a network into more physical segments, resulting in higher overall network bandwidth. Bridges, on the other hand, support only two ports, limiting the physical segments they can create.

3. Transmission Speed: Switches have a faster data transmission rate compared to bridges.

4. Data Frame Forwarding Modes: Bridges typically receive and perform frame integrity checks, such as the Frame Check Sequence (FCS), before forwarding a data frame. Switches, on the other hand, employ two frame forwarding modes: store-and-forward and cut-through. The cut-through mode does not require waiting for the complete reception and CRC calculation of the entire data frame before transmitting the data.

Network bridge vs switch: which one is better?

Bridges and switches are both data communication devices that operate at the second layer of the OSI reference model, commonly referred to as the data link layer. They were initially introduced in the 1980s and were primarily used to connect networks of the same type, facilitating data forwarding between networks. Over time, bridges have evolved to connect different types of networks and have become more intelligent.

As network interconnection devices, bridges can be categorized into several types. Transparent bridges are primarily used in Ethernet environments, source routing bridges are utilized in token ring networks, and translation bridges facilitate data format and protocol conversion between different network media types (typically Ethernet and token ring).

When talking about network bridge vs switch, today, switches have replaced traditional bridges and become the primary networking technology for interconnecting networks. Compared to bridges, switches offer improved data throughput performance, higher port density, lower per-port cost, and greater flexibility and convenience in usage.

From the above introduction, we can see that bridges and switches have many similarities, but there are still some significant differences between these two technologies. In terms of speed, switches are significantly faster than bridges because switches mainly use hardware for switching, while bridges require software to perform switching. Additionally, switches can connect networks with different bandwidths. For example, a 10 Mbps Ethernet LAN and a 100 Mbps Ethernet LAN can be interconnected through a switch. In terms of switching technology, switches support cut-through switching, which can reduce network latency, while bridges can only use store-and-forward technology. Finally, because switches can provide dedicated bandwidth for each network segment, they can reduce collision rates on the network segments.

With the advancement of network technology, bridges, and switches have played crucial roles in enabling seamless data communication and facilitating network expansion and integration. Their continuous development and adoption have contributed to the growth and reliability of modern networks.