Full Mesh Topology

It is used to connect every site with every other site. I am going to draw a figure of mesh topology below:

If A want to connect with B it has got direct link if A want to connect with D again it has got direct link, every client has got direct link this is opposite of hub and spoke topology. This is much more expensive, we are going to pay for WAN links between every two sites. There is a formula for calculating the links

• n(n-1)/2   n = number of sites
• let's suppose n=5 then number of links will be according to formula 5(5-1)/2 = 10 links
• optimal paths 
• not scalable