From: Ondrej Zajicek (work) <santiago@crfreenet.org>
Date: Tue, 5 Nov 2019 15:00:25 +0000 (+0100)
Subject: Doc: Add documentation for BGP option 'allow as sets'
X-Git-Tag: v2.0.8~128
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=d54a69ac7f0a29846cd9dbc697d1d369f51988bb;p=thirdparty%2Fbird.git

Doc: Add documentation for BGP option 'allow as sets'
---

diff --git a/doc/bird.sgml b/doc/bird.sgml
index 384af8357..e0f4fb766 100644
--- a/doc/bird.sgml
+++ b/doc/bird.sgml
@@ -2395,6 +2395,16 @@ using the following configuration parameters:
 	completely disabled and you should ensure loop-free behavior by some
 	other means. Default: 0 (no local AS number allowed).
 
+	<tag><label id="bgp-allow-as-sets">allow as sets [<m/switch/]</tag>
+	AS path attribute received with BGP routes may contain not only
+	sequences of AS numbers, but also sets of AS numbers. These rarely used
+	artifacts are results of inter-AS route aggregation. AS sets are
+	deprecated (<rfc id="6472">), and likely to be rejected in the future,
+	as they complicate security features like RPKI validation. When this
+	option is disabled, then received AS paths with AS sets are rejected as
+	malformed and corresponding BGP updates are treated as withdraws.
+	Default: off.
+
 	<tag><label id="bgp-enable-route-refresh">enable route refresh <m/switch/</tag>
 	After the initial route exchange, BGP protocol uses incremental updates
 	to keep BGP speakers synchronized. Sometimes (e.g., if BGP speaker