Gateway vs Bridge: Difference and Comparison

Key Takeaways

1. Function: Gateway connects different networks, performs protocol translations, and handles routing. A bridge connects LANs within a single network, allowing seamless communication.
2. Network Layer: Gateway operates at the network layer (Layer 3) and handles network protocols. Bridge operates at the data link layer (Layer 2) and focuses on LAN connectivity.
3. Scope: Gateway handles complex network configurations and connects networks of different types. A bridge is used for LAN connectivity within a single network.

What is Gateway?

In an operating systems interconnection (OSI), the element that operates on all seven layers is known as a gateway. It is also considered a protocol converter as it transforms the protocol. 

Using similar packets as a gateway, a router accepts and transfers them across various networks only using multiple protocols. A gateway is also software that must be installed inside a router. 

A gateway follows various steps while accepting a converted packet protocol. The network uses a formatted packet or a protocol from the sender. Initially, the gateway installed in a router receives a formatted protocol, a prominent example of Apple Talk can be considered. 

Then it converts the packet to a different protocol that the receiver’s network will use. In this process, the entire packet format is changed for other protocols. Once the format is changed, the packet is forwarded to various destination networks. 

The packet formatting is done entirely sometimes, or in some cases, only the header and trailer of the packet need to be modified. A gateway can change the rate, size, and format of the data present in the packet. 

What is Bridge?

The operating systems interconnection (OSI) component that operates only on two layers is known as a bridge. A bridge works on the physical and data link layers of the operating systems interconnections (OSI). 

A large segment can be divided into smaller components with the help of a bridge. If two LANs are separated initially, they can be connected using a bridge. A bridge can also transmit various frames between these LANs. 

Once the frame is transmitted, the bridge receives it, and a signal is regenerated. The address of the destination of the receiver of the structure is checked, and a new copy is forwarded of the frame where it belongs or to whichever segment it belongs. 

In the receiver segment, the frame is not broadcasted to all the stations, but it is only broadcasted or sent to its receiver’s station, and the bridge is specific about that. The bridge receives the address of the destination along with the frame, and the lookup table is maintained along with all the physical addresses to which the structure is connected. 

The bridge uses the lookup table to compare the physical address of the receiver’s station on the frame and the received one. Once the match is found, the bridge forwards the structure to its destination.

Difference Between Gateway and Bridge

1. A gateway increases the compatibility of a network; on the other hand, a bridge regenerates the signals in the network. 
2. A gateway works on all the layers of the operating systems interconnection (OSI); on the other hand, a bridge works on only two layers of the OSI.
3. The format of the packet is changed in a gateway; on the other hand, the structure of the packet remains unchanged in a bridge.
4. A gateway operates on all the layers of the OSI; on the other hand, a bridge works on the physical and the data link layers.
5. The operations are conducted on packets in a gateway; conversely, the procedures are performed on frames in a bridge. 

Comparison Between Gateway and Bridge

Parameters of Comparison	Gateway	Bridge
Packet	Changed format	Unchanged format
Router	Installed in a router.	It is not installed in a router.
Work	Converting protocols.	Connecting two LANs.
Subtypes	Unidirectional and bidirectional	Simple, multiport, transparent
Number of layers	7	2

References

1. https://ieeexplore.ieee.org/abstract/document/8514136/
2. https://ieeexplore.ieee.org/abstract/document/5955179/