On Wed, Apr 30, 2003 at 12:34:07PM -0400, Kai Schlichting wrote:
In unrelated news: can someone explain to me the exact meaning of multiple AS numbers enclosed in {}'s (or []'s as far as RIS RIPE's display is concerned) at the end of the AS path?
* 162.33.64.0/19 207.246.129.6 0 11608 2914 3356 14390 {22714,27481} i * 4.0.4.90 1080 0 1 701 14390 {22714,27481} i * 203.194.0.5 0 9942 1 701 14390 {22714,27481} i * 192.205.31.33 0 7018 3356 14390 {22714,27481} i * 195.66.224.82 31502 0 4513 3356 14390 {22714,27481} i * 216.140.2.59 981 0 6395 3356 14390 {22714,27481} i
This means the address space was aggregated by a different AS than originated it, for instance parts of 162.33.64.0/19 were originated by AS 22714 and 27481, but AS 14390 aggregated these to the prefix above. By using the AS_SET notation, one can prevent the loss of origination AS information allowing loop avoidance. -Jon