On dim. 26 mars 09:08:25 2017, Michael McConnell wrote: > Hello all, > > We are running into an issue transiting a down stream ASN. E.g. Uplink > <-> Our ASN <-> Downlink ASN > > To me it seems we should only need to bgp_path.prepend our outbound > filter, however our uplink is dropping the as path when we run it that > way. > > Any suggestions as to what I am missing to carrier a downstream ASN > and prefixes to our uplinks? > > Thanks so much, > Mike
Hi, why do you want to bgp_path.prepend? Your ASN will be automatically
added in the path if you act as transit between upstream and downstream
AS.
Exemple:
template bgp DOWNSTREAM {
import keep filtered;
export all;
}
function bgp_filter_customer_in (prefix customer_prefix) {
if ! (net ~ customer_prefix) then return false;
else return true;
}
filter bgp_filter_customer_petrus_in {
if (bgp_filter_customer_in(2001:678:3cc::/48)) then accept;
else reject "Prefix filtered for petrus";
}
protocol bgp bgp_petrus from DOWNSTREAM {
local as 204092;
description "BGP for petrus";
neighbor 2a00:5884::25 as 206155;
import keep filtered;
import filter bgp_filter_customer_petrus_in;
}
And from another router, we see that:
bird> show route all protocol bgp_grifon_nominoe
2a00:5884::/32 via 2001:7f8:b1::a on eth2 [bgp_grifon_nominoe 12:41:15]
(100) [AS204092i]
Type: BGP unicast univ
BGP.origin: IGP
BGP.as_path: 204092
BGP.next_hop: 2001:7f8:b1::a fe80::215:17ff:fe39:f01a
BGP.local_pref: 100
2001:678:3cc::/48 via 2001:7f8:b1::a on eth2 [bgp_grifon_nominoe 12:41:15]
(100) [AS206155i]
Type: BGP unicast univ
BGP.origin: IGP
BGP.as_path: 204092 206155
BGP.next_hop: 2001:7f8:b1::a fe80::215:17ff:fe39:f01a
BGP.local_pref: 100
So, we have our prefix with just our ASN, and 2001:678:3cc::/48 with our
and the customer ASN.
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