Introduction to the Distributed Systems

JNTU CSE STUDY MATERIAL

A "Distributed System" is a piece of software that serves to coordinate the actions of several computers. This coordination is accomplished by exchanging messages, i.e., pieces of data conveying information. The system links to a network that connects the computers and handles the routing of messages.

Networking Infrastructures: 

i) LAN (Local Area Network's)

ii) P2P(Peer to Peer) Network's 

LAN (Local Area Network's)

LAN's are for example utilized as a part of server farms to interface many servers. Figure demonstrates the primary highlights of a normal Local Area Network (LAN) in this unique situation. We are near three correspondence levels: 

To start with, servers are gathered on "racks", connected by a fast link A run of the mill rack contains a couple of many servers. 

Second, a server farm comprises of an expansive number of racks associated by switches (or switches) that exchange non-neighborhood messages. 

A third (slower) correspondence level, between distinct clusters, may likewise be considered. It can for example permit some free server centers to collaborate, e.g., to merge worldwide insights.

In all cases, servers only to communicate via message passing. They don't share storage or computing resources. The architecture is said "shared-nothing".

Peer-to-Peer Network (P2P).

A P2P network is a particular kind of overlay network, a graph structure build over a native physical network. The physical network we consider here is the Internet. Nodes, or "peers" communicate with messages over the Internet. The route that connects two peers on the Internet is typically intricate. Typically (Figure), a message sent by peer A first reaches a local router, which is sent to peer (local, regional, or world-wide) Until it is delivered to peer B. By abstracting this complexity, a P2P network Imagine a direct link between A and B, as if they were directly connected to each other. This pseudo-direct connection may be more of a message, or "hops", is called an overlay link, hence the term overlay network.