Network node

A node on a network is the equivalent of a vertex in a graph.

A node can represent lots of different things, depending on the context.

Nodes are often connected by arcs to form a network.

Degree of a node

The degree of a node is the number of connections (or arcs) it has to other nodes in the network.

For example, in the following network, the degree of node A is 3, because it is connected to three other nodes (B, C, and D):

     A
   / | \ 
 B   C   D

In a directed network, we distinguish between:

• in-degree: the number of incoming connections to a node.
• out-degree: the number of outgoing connections from a node.