On Fri, Dec 16, 2011 at 07:22:32PM +0000, Alexander Bahoor wrote:
Route metric is a variable that a router uses to choose the best route to a destination.
Depending on the routing protocol, the metric definition is different. What I'm trying
to understand is how Linux defines the metric in the route output command.
For example when a Fedora laptop has two active interfaces, Ethernet and wifi, the metric
in route output, is set to 1 for Ethernet and 2 for WiFi. Reading the man page on the
route command, it says the metric is defined as hop counts to a destination. Based on the
above observation, this is incorrect or incomplete. It definitely include the hop count,
but how fedora came up with 1 and 2. Could it be just used these number arbitrarily to
indicate to IP, that the Ethernet interface is the preferred path to use to send traffic,
because it's speed is faster and more reliable?
Thats pretty much it. If you read the rest of that entry on the man page, the
metric is a user assigned value from a routing daemon (or other utlity), to
indicate path preference when there is a need to make that determination. The
kernel doesnt use it anymore, but some routing daemons do.
Basically what I'm looking for is the definition of the metric
defintion in Linux or Fedora. And if someone shed light on the windows definition that
would be great.
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