Write short notes on Peer-to-Peer (P2P) Network Families.
Answer:-
A Peer-to-Peer (P2P) network is a distributed system where each computer (peer) can act as both a client and a server. There is no central control, and peers can join or leave the network freely.
P2P Systems:
- In P2P, each node shares its own resources (like storage, CPU, or files).
- There is no master-slave or client-server relationship.
- The network is self-organizing with distributed control.
- The physical network is formed by peers using normal Internet protocols (TCP/IP, NAI).
- The topology and size keep changing dynamically based on active peers.
Overlay Networks:
P2P networks work in two layers:
a. Physical Layer:
- The actual connection of peers on the Internet.
b. Logical Layer (Overlay Network):
- A virtual structure formed by mapping peer IDs.
- There are two types of overlays:
- Unstructured – Random connections; uses flooding to find data; not efficient.
- Structured – Uses fixed rules and routing techniques; more organized and faster.
P2P Application Families:
There are four main types of P2P applications:
| P2P Family | Examples / Use |
| File Sharing | Gnutella, Napster, BitTorrent (for sharing music, videos, etc.) |
| Collaboration | Skype, MSN Messenger (for chatting, messaging, teamwork) |
| Distributed Computing | SETI@home (shared computing power from many users) |
| Platform Services | JXTA, .NET P2P, FightingAID@home (for naming, discovery, security) |
Challenges in P2P Computing:
- Hardware Differences – Too many device types and architectures.
- Software Compatibility – OS and software differences cause problems.
- Network Diversity – Different protocols and speeds affect communication.
- Routing Efficiency – It depends on how well peers manage routing.
- Security Issues – Peers are strangers; lack of trust, privacy, and virus risks.
- Fault Tolerance – Systems must handle node failures and load balancing.
- Scalability – The system should grow with more users and still work efficiently.
- Data Management – Data must be located and replicated properly for performance.