On Fri, Mar 09, 2012 at 05:07:37PM +0100, Benjamin Henrion wrote:
On Fri, Mar 9, 2012 at 4:43 PM, Andrew Lunn andrew@lunn.ch wrote:
With such metric, you don't make any difference between a 56K telephone line and a 10Ge NIC.
If you 10Ge has 5pc packet loss and your 56K line has 0pc, your TQ will be prefer the 56k link.
If my 10Ge has 5% packet loss, its broken. I don't want to use it. Falling back to the 56K link is the right thing to do.
There is a general rule of thumb. The higher the bandwidth, the less packet loss there is. This is because high bandwidth links are generally not wireless and so don't suffer high packet loss.
As a side effect, BATMAN will tend to favor wired links over wireless links, because wired links tend to be reliable, wireless links drop packets.
So compare a 1Mbits wireless link with a 54Mbits one.
The 54Mbps link probably has a very low packet error rate. Otherwise it would not be running at 54 Mbps. The automatic rate selection algorithm would take it down to a lower rate if it had high packet loss.
On the other hand, any link running at 1Mbit probably has quite a high packet error rate. It must be a bad link, otherwise it would not be using the lowest possible coding rate.
So when comparing a 1Mbps and a 54Mbps link, probably the TQ for the 54Mbps link will be better than the 1Mbps link.
Andrew