How do routers create a broadcast domain boundary?
a. They listen to and direct broadcast traffic.
b. They only forward broadcasts that are intended for multiple subnets.
c. They forward broadcasts only to necessary segments.
d. They do not forward broadcast traffic.
The correct answer and explanation is :
The correct answer is d. They do not forward broadcast traffic.
Explanation:
A broadcast domain refers to a network segment where a broadcast packet can travel and be received by all devices within that segment. Routers play a critical role in creating broadcast domain boundaries. Specifically, routers do not forward broadcast traffic from one network segment to another. This ability to block or limit broadcast traffic is what creates the boundary between broadcast domains.
Here’s how it works:
- Broadcast Traffic: When a device in a network sends a broadcast packet, it sends the data to all devices in its immediate network. Devices within the same broadcast domain will receive the broadcast message and process it. This is typically done using a broadcast address, such as 255.255.255.255 in IPv4.
- Routers and Broadcasts: Routers are designed to operate at Layer 3 (the Network Layer) of the OSI model, which involves routing packets between different networks or subnets. A router does not forward broadcast packets from one subnet to another. Therefore, if a broadcast packet is sent on one subnet, it will not pass through a router to reach another subnet.
- Impact on Broadcast Domains: By not forwarding broadcast traffic, routers effectively segment the network into different broadcast domains. This means that broadcast traffic in one subnet will not affect devices in other subnets. For example, a broadcast packet generated in Subnet A will not reach devices in Subnet B, even if both subnets are connected through a router.
- Why is This Important?: Limiting the spread of broadcast traffic reduces network congestion. Broadcast traffic can be resource-intensive, as it is sent to all devices in the domain, even if only a few of them need the data. By isolating broadcast traffic to individual broadcast domains, routers help maintain network efficiency and reduce unnecessary load on devices that don’t need to process the broadcast.
This ability to stop broadcast traffic from flowing between subnets is crucial for maintaining manageable and efficient network topologies.