Routing Folks, I've been looking over the 'advisory' attribute, mostly in preparation for the upcoming RIPE-181 to RPSL conversion (RPSL does not have this attribute). The advisory attribute itself suffers from a severe lack of documentation. In the current database documents, we see the following: RIPE-157: listed as for the route object, with the format <ASnnnn> <as-specific information> RIPE-181: not present RIPE-189: in the route template only As for how the attribute is actually used, I found 2726 route objects with the attribute. Of these, there are only 111 unique origin AS. As for the AS actually listed as the target of the advisory, there are only 13 unique AS! The actual frequencies are: AS517: 8 AS670: 1 AS690: 2703 AS702: 2 AS1275: 13 AS1717: 1 AS1755: 2 AS2917: 5 AS3220: 3 AS3257: 1 AS3328: 1 AS3561: 1 AS6830: 2 AS690, the Merit network, seems to have a specific format for their advisory attribute (which I can guess at, but not really be sure what it means). This is not shared by all of the other AS's who use the advisory attribute. So, some questions are: Is there a BCP for this attribute? And can anyone explain how and why it is used? Can somebody suggest an alternative method to obtain the same results in RPSL? And finally, what should the method be during RIPE-181 to RPSL conversion? -- Shane Kerr <shane@ripe.net> Database Software Engineer RIPE NCC +31 20 535 4427