# Full mesh topology

Member Posts: 31 ■■□□□□□□□□
Many thanks for previous replies.
I have a new problem, reference the number of total physical connections for a full mesh system.
There is one formula total number of connections= n(n-1) where n= the number of devices.
And total number of connections = n(n-1)/2.
I think the correct one is n(n-1) ?

• Member Posts: 1,506
In full mesh network, each device has a n-1 number of connections.
And there is a total of n(n-1)/2 number of connections.

This is because the connections are bi-directional. So A-B, and B-A is the same connection. So dividing by 2 removes the duplicates.
Jack of all trades, master of none
• Member Posts: 1,243
Well, the number of connections would be n(n-1), but the number of links would be n(n-1)/2. Each link has 2 connections.
• Member Posts: 1,506
Danman32 wrote:
Well, the number of connections would be n(n-1), but the number of links would be n(n-1)/2. Each link has 2 connections.

I dont remember if 'link', and 'connection' were the terms, I have a feeling it might be the other way around..... but you are very right, I apologize, there is a huge distinction.
Jack of all trades, master of none
• Member Posts: 10 ■□□□□□□□□□
Sorry to necro this, but any tips on recognizing which one is right? I got a practice exam connection that used the term 'connections' and had the n(n-1) formula. This is the ONLY place I had ever seen this formula, because honestly no one cares about that, what they care about is how many cables or a-b connections are needed.

So I don't know if the practice question was wrong, or if it was just referencing something very rare, and now I'm worried that a question on the actual exam is going to confuse me.