[Nodeshot] TX, RX rate

[nemesis]

 In the new database, every interface type has a tx_rate and rx_rate 
 field.

 The link table has a tx_rate and rx_rate too, which in the beginning 
 the idea was to represent the average between interface A and interface 
 B (a link connects two interfaces).

 Interface types can vary: ethernet, wireless, tunnel, bridge... we'll 
 work out in details these later.

 My question is: does it have sense to have the tx_rate and rx_rate on 
 every interface?

 Or is mainly a proprety related to wireless interfaces?

 Does it have sense for example.. to have tx_rate and rx_rate on a vpn 
 interface? Or on a bridge interface?

 Going back to links... does it really have sense to have tx/rx on the 
 link? If yes should it be the average between the two interfaces or one 
 of the two? I remember having discussed this with some of you.. probably 
 ZioProto but cannot remember right now.

 So to summarize, the questions are:

 * should every interface type have tx_rate and rx_rate or not?
 * if not, which types?
 * should link objects have tx_rate and rx_rate?
 * if yes how should those values be determined?

 Try to keep it short and concise!

 Nemesis

 PS: now I need to sort out some technical doubts, in the next weeks, 
 starting from tuestady we'll discuss more the web interface
 PPS: in the next days I'll try to prepare a database diagram for these 
 type of questions so it will be easier to understand and answer