RE: Determine difference between 2 BGP feeds
Sounds to me like one of your providers is not feeding you the full internet routing table. Have you checked with them to see if they are providing you that? Mike Walter Systems Administrator -----Original Message----- From: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu] On Behalf Of Scott "Tuc" Ellentuch at T-B-O-H Sent: Tuesday, April 18, 2006 4:13 PM To: nanog@merit.edu Subject: Determine difference between 2 BGP feeds Hi, We receive a BGP feed from different providers on two different routers. While one seems to be a reasonable amount of feeds after reviewing the CIDR report, the other is anywhere from 3K to 10K more routes. Is there a utility that I can use that will pull the routes off each router (Foundry preferred), and then compare them as best it can to see why there is such a difference? I can understand a handful of routes over what CIDR says, but a minimum of 3K more? Thanks, Tuc/TBOH
On Apr 18, 2006, at 1:19 PM, Mike Walter wrote:
Sounds to me like one of your providers is not feeding you the full internet routing table. Have you checked with them to see if they are providing you that?
Sounds to me like a: you are only looking at best routes or b: one of the providers is sending you more specific customer routes (that they summarize before sending to non-customers). Personally I would just slurp one set of routes into an array in perl and then delete them if they appear in the other set. Any left over in either set are unique.... W
Mike Walter Systems Administrator
-----Original Message----- From: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu] On Behalf Of Scott "Tuc" Ellentuch at T-B-O-H Sent: Tuesday, April 18, 2006 4:13 PM To: nanog@merit.edu Subject: Determine difference between 2 BGP feeds
Hi,
We receive a BGP feed from different providers on two different routers. While one seems to be a reasonable amount of feeds after reviewing the CIDR report, the other is anywhere from 3K to 10K more routes.
Is there a utility that I can use that will pull the routes off each router (Foundry preferred), and then compare them as best it can to see why there is such a difference? I can understand a handful of routes over what CIDR says, but a minimum of 3K more?
Thanks, Tuc/TBOH
-- Some people are like Slinkies......Not really good for anything but they still bring a smile to your face when you push them down the stairs.
More than likely, one provider is feeding too many routes -- some that I have run across tend to feed more specific internal routes (read: redistributing IGP into BGP) to customer BGP sessions. The two I've run across, after I yelled, they fixed. On Tue, 18 Apr 2006, Mike Walter wrote:
Sounds to me like one of your providers is not feeding you the full internet routing table. Have you checked with them to see if they are providing you that?
Mike Walter Systems Administrator
-----Original Message----- From: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu] On Behalf Of Scott "Tuc" Ellentuch at T-B-O-H Sent: Tuesday, April 18, 2006 4:13 PM To: nanog@merit.edu Subject: Determine difference between 2 BGP feeds
Hi,
We receive a BGP feed from different providers on two different routers. While one seems to be a reasonable amount of feeds after reviewing the CIDR report, the other is anywhere from 3K to 10K more routes.
Is there a utility that I can use that will pull the routes off each router (Foundry preferred), and then compare them as best it can to see why there is such a difference? I can understand a handful of routes over what CIDR says, but a minimum of 3K more?
Thanks, Tuc/TBOH
-- Alex Rubenstein, AR97, K2AHR, alex@nac.net, latency, Al Reuben Net Access Corporation, 800-NET-ME-36, http://www.nac.net
More than likely, one provider is feeding too many routes -- some that I have run across tend to feed more specific internal routes (read: redistributing IGP into BGP) to customer BGP sessions.
The two I've run across, after I yelled, they fixed.
I quickly took a look for anything less than a /24 (Not that you can't route /24s in IGP) and that accounts for 25% of the overage : /25 - 274 /26 - 178 /27 - 165 /28 - 123 /29 - 114 /30 - 116 /32 - 47 Continuing to see what I get... Tuc/TBOH
participants (4)
-
Alex Rubenstein -
Mike Walter -
Scott Tuc Ellentuch at T-B-O-H -
Warren Kumari