A stub network, in the context of computer networking, refers to a network or subnet that has only one route to reach other networks. It is called a "stub" because it lacks redundant or alternative paths for traffic to flow beyond its boundaries. In simpler terms, a stub network is a network that does not function as a transit or forwarding point for data packets destined for other networks.

In a typical network architecture, routers are responsible for forwarding data packets between networks. When a router receives a packet, it examines the destination IP address and determines the most appropriate path to forward the packet. However, in the case of a stub network, the router handling the stub network will have only one path available to reach destinations outside of the stub.

There are a few key characteristics that define a stub network:

1. **Single Exit Point**: A stub network has a single exit point, which is the router connecting the stub network to the rest of the network infrastructure. All traffic leaving the stub network is directed through this exit point.

2. **Limited Routing Information**: Stub networks do not maintain or propagate detailed routing information about other networks. They typically have minimal knowledge about external routes beyond their own network.

3. **Minimal Redundancy**: Due to the absence of alternative paths, stub networks have limited redundancy. If the router connecting the stub network to the rest of the network fails, connectivity to external networks may be lost.

Stub networks are commonly found in small-scale network deployments, such as small office or home networks, as well as in certain branch office configurations. They are also used in network topologies where simplicity and reduced complexity are desired.

While stub networks may have limited functionality in terms of routing and redundancy, they offer advantages in terms of simplicity and reduced administrative overhead. They can be easier to manage and troubleshoot compared to more complex network architectures.

It's worth noting that stub networks can still communicate with external networks by utilizing network address translation (NAT) techniques. NAT allows devices within the stub network to share a single public IP address when communicating with external networks, enabling them to access the Internet or connect to remote services.

In conclusion, a stub network is a network or subnet with a single exit point and limited routing information, lacking redundant paths to other networks. While it may have limitations in terms of routing and redundancy, it offers simplicity and ease of management in certain network deployments.