Self Doubt

Question

Switch can't reduce broadcast domain because it is not a network layer device.Is my reasoning correct?

Answer 1

Yes . It will reduce collision domain but not broadcoast domain .

 

Collision domain

A collision domain is, as the name implies, a part of a network where packet collisions can occur. A collision occurs when two devices send a packet at the same time on the shared network segment. The packets collide and both devices must send the packets again, which reduces network efficiency. Collisions are often in a hub environment, because each port on a hub is in the same collision domain. By contrast, each port on a bridge, a switch or a router is in a separate collision domain.

Broadcast domain

A broadcast domain is a domain in which a broadcast is forwarded. A broadcast domain contains all devices that can reach each other at the data link layer (OSI layer 2) by using broadcast. All ports on a hub or a switch are by default in the same broadcast domain. All ports on a router are in the different broadcast domains and routers don’t forward broadcasts from one broadcast domain to another.

 

IMPORTANT :remember, each port on a hub is in the same collision domain. Each port on a bridge, a switch or router is in a separate collision domain

 

 

Comments

Why in bridge collision domain decreases (but not to 0) and in switch it decreases to 0 ?

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@Smishra95 Why is each port on a bridge, switch, and router in separate collision domain?

According to me:

Switch and router will not allow packets to cross them if they belong to the same network. And also if the packets sent by two hosts belong to the same network then also collision domain remains the same, as the collision can happen from the originating network.

But bridge does not have any restriction like that, therefore it will not reduce the collision domain to zero but as it stores and then forwards the packets hence the collision domain will decrease.