manipulating the best path, eBGP, MED?

Stefan Jakob tinysammy at gmail.com
Tue Mar 7 20:28:20 CET 2017


Hi Thomas,


You could also consider to prepend your AS in the path. Just some random
google result:

https://www.juniper.net/documentation/en_US/junos/topics/usage-guidelines/policy-prepending-as-numbers-to-bgp-as-paths.html

In Bird:

export filter {
	if source = RTS_STATIC then {
		bgp_path.prepend(65000);
		accept;
	}
	reject;
};

Our an unchecked adoption of your example:

# your default gateway IP below here
protocol bgp eBGP {
import none;
export  filter {
          where proto = "static_packet";
           # 65000 -> put you AS here or define variable
           bgp_path.prepend(65000);
           # bgp_med = 100;
           };
local as 65000;
neighbor 10.80.x.x as 65530;
password "SECRET";
}

Another option might be to ask for BGP ecmp on transit side.

Hth, SJ


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