Introduction to Bridge
In today’s world of networking, “Bridge” is an important terminology and is defined as a computer network device that provides interconnection between other bridge networks. It is very analogous to a bridge that connects two portions of land. Like the bridge connecting two parts of land so as to fill up the space to cross a gap or open space, the network bridge also connects two parts of a network at a data link layer. Bridge networks connect two different networks and provide communication between them. This network device works on OSI (Open System Interconnect) layer 2. In this article, we will see various similarities of bridges with other devices and also try to find subtle differences that differentiate bridges from any other device.
Here are the following Terminologies mention below
1. OSI Model
A conceptual model that enables the standardization of communication function. In this model, the entire communication system model is partitioned into abstraction layers. The layers are:
- Physical Layer
- Data Link layer
- Network Layer
- Transport Layer
- Session Layer
- Presentation Layer
- Application Layer
In layer 2, is where the bridge works in the communication channel.
The switch is networking hardware that enables connection in a computer network by using packet switching for receiving and forwarding data to the destination device. Packet switching is a methodology in which data is grouped into packets over the digital networks. It helps in boosting of efficiency of Bridge.
The repeater is a Layer 1 components of a network. Repeater helps in regenerating signals over the same network before the network goes weak or corrupted. And hub is basically a multiport repeater.
4. MAC address
MAC stands for Media Access C On a lighter note MAC address is nowhere connected to Apple products. This address helps in the unique identification of a device in the network. It is very analogous to the fingerprint/retina of a person. No two fingerprint/retina will be same and same is for MAC, i.e. no two MAC address is the same for different devices. Currently, the MAC address is two 6-digit hexadecimal numbers, separated by colons.
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As discussed above, It acts as a connection between two parts of a network at a data link layer of the OSI model. They are primarily used in local area networks because of their ability to broadcast data to all nodes thus leading to clog and the flood of the network. The working principle of the bridge is very similar to switch, but the traffic is managed differently in bridge than switch. A Bridge is also a repeater working on layer 2 with the addon functionality of filtering MAC addresses.
When we use the Bridge?
- Before we dive into when we use the bridge, let’s see how bridgework. From incoming network traffic, a bridge when it receives the signal inspects that and then determines whether to forward or discard the traffic or signal according to its intended destination.
- For example, an ethernet bridge inspects each incoming Ethernet frame including the frames having source and destination MAC address. And then forwards the individual decision of what needs to be done with the signal. Bridge gas a single input and a single output thus making it a 2-port device. It is reliant on the database to ascertain the route of passing, transmitting or discarding a signal.
- With the active involvement of the data frame if the frame received is for the segment which resides on the same host network the frame will be passed to that node and the bridge on the receiving end will then discard it. If the frame has a MAC address of the connected network, it will forward the signal/data.
- Now coming to on when we use a bridge. Though there are other network devices present, when do we use the bridge? In the next section, we would look into the advantages of the bridge thus answering the question of why we use them.
When do we use the bridge?
- When packets of data are transferred without locating addresses.
- When we need to locate an unknown address to which it is viable to send a message.
- When remembering and recalling the addresses of devices for future transmission is required.
- Commonly used in token ring networks.
- When 2 LAN works on the same protocol.
Advantages of Bridge
- They are simple to use and relatively inexpensive.
- The data load is lowered over the data link layer.
- It can be made intelligent by effectively coding to reject any signal or packets from meticulous networks.
- They are translucent over the MAC layer.
- If the user wants to lower the bandwidth utilization bridges come in very handy.
- It enables reducing the network traffic by subdividing the load through various communications.
- It helps in extending a network by acting as a repeater and also helps reducing collisions.
- Network bandwidth in an individual node is increased as fewer nodes share a collision domain.
- Though there are noticeable advantages of a bridge, no network device can be a perfect device. It has some noticeable disadvantages. It can’t identify the types of broadcast messages and thus unable to filter them, thus leading to the transfer of all types of broadcast messages and hence unable to limit the scope of the transfer.
- It is more expensive than repeaters or hubs, but the extra cost is a trade-off of it being extra intelligent. Since filtering takes place in bridges, it is somewhat slower than repeaters or hubs. It helps in buffering data frames and thus it affects performance. Though the disadvantages are not that noticeable looking at the advantages, It is an important networking device in today’s world and it is used extensively!
This is a guide to What is Bridge?. Here we discuss the terminologies and advantages of Bridge along with why and when we use it?. You may also look at the following article to learn more –