A network is formed when two or more devices connect to share data or resources. A large network may need to be broken down for efficient frame delivery or traffic management. Bridges or switches are used to connect these divided segments of networks. In a long way, the terms bridge and switch are used interchangeably. Bridge and switch both provide the same functionality, but the switch does it more efficiently.
A bridge connects smaller network segments to form a large network, and also forwards frames from one LAN to another LAN. On the other hand, it switch connects more network segments than bridges. This is a fundamental difference between bridge and switch. Let us compare the differences between the bridge and move on with the help of the comparison table shown below.
|Basic||A bridge can connect fewer LANs.||A switch can connect more networks than the bridge.|
|Buffer||Bridges don't have buffers.||Switch has a buffer for each link connected to it.|
|types||Simple bridge, multiport bridge and transparent bridge.||Store-and-forward switch and cut-through switch.|
|Error||Bridges do not perform error checking.||The switches perform error checking.|
Definition of Bridge
Bridge a device network used to connect network segments of a large network. Bridge operates on two levels, for example level physical and data link level . Being a physical device, regenerates the signal it receives. Here, it acts as a relay .
Being a device at the data link level, the bridge identifies the address of origin and destination of the frame it receives. Transmits frames between two separate LANs. On the other hand, bridge also has the logic of filter traffic (separating traffic from each network segment).
The filtering capacity of Bridge can be explained with an example. It is possible to observe the figure above, a bridge has joined two network segments. Now when the station TO send a packet to the station F, the package reaches the bridge. The bridge identifies that the intended recipient F yes located in the lower segment of the network. Thus, the bridge allows the packet to cross the lower segment where the packet is received by the station F.
When the station TO send a packet to the station C, the package reaches the bridge. Because the stations TO is Yes found in the same segment, the bridge blocks the packet from crossing the lower segment and transfers the frame to the station C.
In addition, we will discuss the types of bridges. Simple Bridge the most primitive bridge connecting two network segments. It has one single table which contains the address of each station included in both segments.
Multiport Bridge, connects more than two network segments. It has the number of tables equal to the number of network segments it connects. Each table contains the addresses of all the stations reachable from the corresponding door. Transparent Bridge a bridge whose existence is unknown to stations. If a transparent bridge is added or removed from the system, there is no need to reconfigure the stations.
That's all about bridges. Now let's move on to switches that are similar to bridges.
Definition of Switch
Whenever we talk about switches, we have to specify the level at which the switch operates. We have two types of switches: a switch a two levels and one a three levels . The two-level switch operates on two levels, for example a layer of physical and data link . A two-level switch has functionality similar to that of a bridge but it has faster forwarding capacity and greater efficiency. On the other hand, a three-level switch acts as a router that receives, processes is forwards the package.
In this article, we are discussing two-tier switches that look like i multiport bridge . Can connect multiple network segments. A switch has a buffer for each link connected to it. Here, the receive link buffers store the packet and check the outgoing link. If the outbound link is free, switch sends the packet over the outbound link.
Switches are built on two strategies that are store-and-forward is cut-through . The switch store-and-forward stores the frame in the receive link buffer until the whole packet arrives. On the other hand, it cut-through switch forward the packet as soon as the destination address of the frame is identified.
Each switch has a control unit it's a switch table . The control unit processes the frame to find the destination address of the frame and consults the switch table to find out which connection the desired receiver is connected to.
Key differences between bridge and switch
- Bridges generally connect fewer networks than the switch.
- Switch has a buffer for each link connected to it which is missing in a buffer.
- Switch performs error checking which is not executed in a buffer.
- Bridges are classified as a simple bridge, a multiport bridge is a transparent bridge . On the other hand, a switch can be classified as a switch Store-and-forward is switch cut-through .
Bridges were introduced when classic Ethernet was used, so they tend to join fewer networks. Switches are modern bridges and tend to join multiple networks together and are more efficient than bridges.