On 10.2.2010 P3. 21:32, Stuart Henderson wrote:
On 2010-02-10, Ivo Chutkin<open...@bgone.net> wrote:
Hello misc,
Would the following filter work?
match to $my_upstream_1 source-as {some_as} set prepend-self 4
I would like to prepend my as to make as path longer for "some_as"
trough my_upstream_1 and make it to prefer path trough my_upstream_2.
It does not produce error with bgpd-n but there is no effect as well.
Are you certain it has no effect (and how?) - you can't rely on
AS path prepending to change how traffic flows, if someone gives you
a higher localpref they'll use that path irrespective of the path length.
Hi Stuart,
I am "certain" as I don't see my prepend on some_as looking glass.
The actual filter looks like this without the comment:
match to $spnet_bg #(AS8717) sourse_as 9070 set prepend-seff 4
and this is what I see on 9070 looking glass:
inet.0: 5185 destinations, 8315 routes (5184 active, 0 holddown, 1 hidden)
+ = Active Route, - = Last Active, * = Both
A Destination P Prf Metric 1 Metric 2 Next hop AS path
* 87.120.100.0/24 B 170 115 >212.116.129.38 34224
20682 I
B 170 115 999999 >212.116.129.66 34224
20682 I
B 170 115 >212.116.135.81 8717
20682 I
{master:0}
where 20682 is my as.
Filter like:
match to $spnet_gl prefix {$net3 $net4 $net5 $net6} set prepend-self 2
works perfect but it prepends all as paths from this neighbor and it
changes the routes to me.
I am aware of local preference.
Thanks for the help,
Ivo
