- A bridge has two layers: Physical layer and the data link layer.
- It can perform all the task that device with the physical layer performs additional because of the data link layer it can perform some other tasks.
- It is used to connect two different types of LANs.
- It is a store and forward device. Inside a bridge, a collision domain is very less.
Because of the data link layer, it has some other functionality:-
- It can see the mac address contained in the frame.
- It has filtering capacity so Collison is very less or negligible.
- It can't change the mac address.
A bridge has two types of tables: static table and dynamic table.
Bridge uses tables to map the incoming frames to respective ports.
As the name suggests a transparent, all the other stations are unaware of the existence of that bridge.
A system with a transparent bridge must meet the following criteria:-
Forwarding Learning and No looping.
1. Forwarding: means bridge should forward the frame to the correct destination.
2. Learning: means automatically updating the table with the help of flooding. To make a table dynamic, we need a bridge that gradually learns from the frame movements. To do this, the bridge inspects both the destination and the
When two LANs are connected using two bridges looping problem happens.
Bridges use a spanning tree algorithm to solve the looping problem.
let's understand this looping problem with one diagram: