diff --git a/ryu/lib/packet/bgp.py b/ryu/lib/packet/bgp.py
index 7d09c923..716d1e3f 100644
--- a/ryu/lib/packet/bgp.py
+++ b/ryu/lib/packet/bgp.py
@@ -55,7 +55,11 @@ BGP_ERROR_CEASE = 6
 _VERSION = 4
 _MARKER = 16 * '\xff'
 
-BGP_OPT_CAPABILITY = 2  # RFC 3392
+BGP_OPT_CAPABILITY = 2  # RFC 5492
+
+BGP_CAP_MULTI_PROTOCOL = 1  # RFC 4760
+BGP_CAP_ROUTE_REFRESH = 2  # RFC 2918
+BGP_CAP_FOUR_OCTET_AS_NUMBER = 65  # RFC 4893
 
 BGP_ATTR_FLAG_OPTIONAL = 1 << 7
 BGP_ATTR_FLAG_TRANSITIVE = 1 << 6