Bridge Types | Local | Remote | Transparent | Translational | Source-route | Advantages
A bridge is a networking device of the computer that connects one network bridge with other network bridge that uses the same protocol (protocol is a set of rules that must be followed for networking activities).
In OSI model Bridge work at the data link layer connect two networks together and provide communication between them is also used to connect two LAN that use the same protocol. it only supports only one input and output port, that’s the way it is called two-port device. Working of the bridge is the same as repeater and hubs. In the same way, they also use to broadcast data to every host. But bridge also maintains MAC (Media Access Control), this is addresses table it maintains the address that’s way data send to its desired recipient easily.
Bridged networks will send the packets of all higher-layer protocols that may be running on the network. Any LAN protocol can be bridged, the most of LANs today are Ethernet switched LANs, and most bridges are thus Ethernet bridges. Bridges are hardware based, and it uses special hardware known as ASIC (Application specific integrated circuit) chip which used to maintain MAC address table and to make a filtering decision
A bridge connects LAN segments to form a single network that appears as a continuous Level two LAN.
Difference between routers and bridges
The main difference between Bridge and Router is that Bridge is a network device basically works at the data link layer of the OSI (Open System Interconnection) model with receiving and sending frame abilities. It reads the MAC address of the device; it works on a single broadcast domain.
While the Router is an internetworking device work at the network layer of the OSI model. A router is used to connect to the two or more networks and transmit packets from one network to another. It reads the IP address of the device. It works on one or more domain.
A bridge can also be combined with a router sometimes in a product is known as brouter but this is not commonly used. Most routers will have some support for bridging features.
Models of bridging
There are two common models of bridging:
Local bridging is created by connecting the LANs connection with local cables. Local Bridging is most commonly used, used in data centers
Remote bridging is where two bridges are connected through a wide area network (WAN). It mostly connects one or more LAN through a WAN.
A simple bridge will transmit those packets which it receives, it means there is no specific segmentation and that traffic increase issues are inevitable. To avoid this situation, advanced bridges are used, such as transparent and source-routing bridges, these bridges use a forwarding table to determine the path from the LAN where a packet arise to the bridged LAN where the destination lies in this way, deliver only to the destination LAN segment. If there are many paths are present, this can make a loop where packets again boost until they use all LAN.
Early models of bridging used Spanning tree ( is an algorithm that avoids looping) this algorithm to check the best path to covering all available destinations and kill looping. But the modern access is to use multiport bridging, which checks a complicates bridging configuration where LANs have many accessible bridge connections between them, making it a “shortest path specification. This is the best approach to creating a Strong bridged network.
How Bridges Works
When different network segments are built at the data link layer of the OSI (open system interconnection) model, we call to it as a bridge. However, when the packets of data are transmitted within a network, without putting the network addresses this processor packet is known as bridging.
The bridging process provides help in placing the addresses of unknown addresses to which it is detected to send data. In the bridging process, the data packets have a header (contain extra transparent information about packet) or a packet header which holds the address to the expected device. The bridge can remember this address and again call the address of the devices for more transmission. There are two types of bridging modes, the transparent bridging, and the source routing bridging.
When the process of bridging appears, it constructs a bridging table forth side where MAC addresses will store the various devices or nodes. This table provides help bridges to transmit the data packet to the desired or correct destination next time. When the desired address does not match with the addresses of the bridging table, the data packet is sent to every connected node in LAN except the computer or device it is connected to. This type of bridging is known as transparent bridging.
Source route bridging
When the source computer provides destination address along with the packet, this type of bridging is called source route bridging. It is most widely used on Token Ring networks.
Major limitations of network bridges
A network bridge does not draw any connection between network path and the physical hosts of the data. There is no guideline for data packets for travelling. Therefore a network data packet is transmitting to every network node.
The bridge does not provide any physical address of any connected node. That’s way a data packet is transmitting to every address. This is a bad way of transferring data. Weaken overhead can occur in chunky and slow links.
Advantages and disadvantages of network bridges
There are many advantages and disadvantages of using network bridges.
Advantages of bridges
- Bridges have simple structure.
- Bridges are simple to use and they are almost inexpensive.
- It can be used as an alternative of switches and help to result in micro segmentation.
- Bridges can be effectively programmed to disallow packets from accurate networks.
- Bridges are more reliable.
Disadvantages of bridges
- Bridges cannot read a specific IP address; they are more work with the MAC addresses.
- Bridges cannot help to provide a communication network between the networks of different protocol
- Bridges transfer all types of broadcast messages, thus bridges are cannot limit the capacity of these messages.
- Very large networks cannot run on bridges; because the large networks like WAN which use IP addresses cannot make use of it.
- Bridges are expensive than Hub and Repeater
- Bridging is most convenient to be used for LAN network traffic data load.
- It cannot handle more complicated variable data load such as occurring from WAN.
Types of Bridges
Three types of bridges are used in networks.
A transparent bridge is not visible to the other devices on the network. Transparent bridges can only perform the function of blocking or sending data depend on the MAC address; the devices on the network are unconnected to these bridges’ presence. Transparent bridges are most common types of bridges.
A translational bridge can be changed from one networking system to another. it translates the data it receives. Translational bridges provide a connection for two different networks, such as Ethernet and Token Ring networks. Depending on the direction of transmission l, a translational bridge can add or remove information and fields from the frame according to need.
Source-route bridges were developed by IBM for use on Token Ring networks. The source-route bridge derives its name from the basis that the entire direction of the frame is added within the frame. This allows the bridge to make exact decisions about how the frame should be sent via the network.