On Thu, 24 Oct 2013 15:05:21 +0200 Denis Walker <denis@ripe.net> wrote:
Although the proposal had received some support when discussed recently on the Database Working Group mailing list, there was some discussion during the RIPE 67 Routing Working Group session that the community field can be used to achieve the same result as these proposed "via" attributes. However, some people have commented that the community field cannot be used for this purpose with 32-bit AS Numbers. As a result, the RIPE NCC was asked to bring the issue back to this mailing list for further discussion.
Overloading of the community field is something that is done by current route server operators. This is because of the lack of a proper alternative. While it is something that works for most cases, it does not accurately describe the actual policy. An example: export: to AS6777 action community .= { 6777:6777, 6777:64514, 6777:64515 }; announce AS1200 This specifies that routes are being sent to AS6777 tagged with a set of communities. Without the additional knowledge of how AS6777 treats these communities it is not at all clear that this policy in fact describes a peering relationship between AS1200 and AS64514/AS64515 via the Multi-Lateral Peering service operated by AS6777. The "import-via/export-via" attributes would allow operators to accurately describe these indirect adjacencies, because it actually defines 64514 and 64515 as Autonomous System numbers. Furthermore, the community-approach is problematic due to the lack of room for specifying policies for 32-bit ASNs, which has already been mentioned in this thread. For the above two reasons I would like to see these attributes implemented. Kind regards, Martin