# Host Roles
- To be a part of a global community, a device must be connected to a network connected to the internet. 
- All devices connected to a network and participate directly in net communication are classified as hosts. Some hosts are called end-devices, some clients. The term host is refers to any device given a number for communication purposes to identify it.
- This number is referred to as an IP ( Internet Protocol ) address, which identifies the network and host.
- An example of a client is a browser ( Firefox, Chromium, Safari, etc ). A computer can run many types of client applications ex. a user can check email and view a web page while instant messaging and listening to an audio stream.

# Peer-to-Peer ( P2P )
- Client and server software usually run on separate devices, however one computer can be used for both roles - this is defined as a Peer-to-Peer network: a device functions as both a server and a client.
- For example, in the figure below, a print sharing PC has a USB connection to the printer, with a network connection to the file sharing PC using a NIC. This allows the file sharing PC to print files, routing through the print sharing PC.
![](Pasted%20image%2020240125163704.png)
## Advantages 
- Easy setup
- Low complexity
- Low cost, dedicated servers not required, and networking equipment not required
- Can be used for simple tasks ( File transfer, print sharing )

## Disadvantages
- No central admin
- Not secure
- No scalability
- Multi-use devices must dedicate resources to both client and server tasks.

# End Devices
- Each end device has an IP address
- When communication initiated, an IP address is referenced to indicate the destination
- End device can either be the source or destination

# Intermediary Devices
- Connect the end device to a network. 
- Can connect multiple networks together to create an internetwork
- Use end point IP address, with information about