thanks all, this makes sense now. and i just showed the internet how ignorant I am… i have my maxas-limit set to 10 based on an article I was reading. perhaps I should up that a bit. what sort of problems are associated to overly long AS paths? is it more of a system resource control setting? -g On Nov 10, 2010, at 3:31 PM, Nick Olsen wrote: They are prepending routes. Looks like both 43022 are prepending, As well as 47359...Multiple times... They do this to make that route look "bad" so it comes in other transit they have. Nick Olsen Network Operations (855) FLSPEED x106 [http://www.flhsi.com/files/emaillogo.jpg] ________________________________ From: "Greg Whynott" <Greg.Whynott@oicr.on.ca<mailto:Greg.Whynott@oicr.on.ca>> Sent: Wednesday, November 10, 2010 3:23 PM To: "nanog@nanog.org<mailto:nanog@nanog.org> list" <nanog@nanog.org<mailto:nanog@nanog.org>> Subject: AS path question. Recently I adjusted the maxas-limit option on our router, logs started reporting routes being refused because the AS path is to long. seems to work as expected. when I looked at the logs I was a bit confused at what i was looking at... why is it there are multiple AS's in the path that appear to be the same AS? I expected an AS path comprised of mostly unique ASs. instead of this: 476330: Nov 10 14:55:07.247 EDT: %BGP-6-ASPATH: Long AS path 549 26677 6939 21011 43022 43022 43022 43022 43022 47359 47359 47359 47359 47359 47359 47359 47359 received from isp router: More than configured MAXAS-LIMIT i expected it would look more like: 476330: Nov 10 14:55:07.247 EDT: %BGP-6-ASPATH: Long AS path 549 26677 6939 21011 43022 47359 received from … .. . thanks for your time again, greg -- This message and any attachments may contain confidential and/or privileged information for the sole use of the intended recipient. Any review or distribution by anyone other than the person for whom it was originally intended is strictly prohibited. If you have received this message in error, please contact the sender and delete all copies. Opinions, conclusions or other information contained in this message may not be that of the organization. Gregory Whynott Network Operations Ontario Institute for Cancer Research MaRS Centre, South Tower 101 College Street, Suite 800 Toronto, Ontario, Canada M5G 0A3 Tel: 647-294-2813 www.oicr.on.ca<http://www.oicr.on.ca/> ________________________________ -- This message and any attachments may contain confidential and/or privileged information for the sole use of the intended recipient. Any review or distribution by anyone other than the person for whom it was originally intended is strictly prohibited. If you have received this message in error, please contact the sender and delete all copies. Opinions, conclusions or other information contained in this message may not be that of the organization.