[rbak-nsp] strange BGP printouts...

Marcin Kuczera marcin at leon.pl
Sat Jan 14 18:24:02 EST 2012


ripleyron at gmail.com wrote:
> Not really, the originator of the route comes from an igp, this is pretty much all the time, it' advertised to the world and you receive it via your external eBGP session, but the initial origin of the route is preserved in the AS-PATH.
> 
> if you have two eBGP sessions with two different upstream providers, you'll likely see differences in as-path etc.

Ok, prefix is allways sources by some IGP - maybe except quagga where 
"network 'prefix'" doesn't require IGP to put this prefix in routing 
table ;)

However look at printouts of advertised routes copied fom below:
 >>>> [bgp1]R0_SE600#show bgp route neighbor 91.195.159.6 advertised
 >>>> Address Family: ipv4 unicast
 >>>> BGP table version is 24923469, local router ID is 195.66.73.250
 >>>> Status codes: d damped, h history, > best, i internal
 >>>> Origin codes: i - IGP, e - EGP, ? - incomplete
 >>>>
 >>>> Network            Next Hop                Metric  LocPrf  Weight Path
 >>>>> 31.11.128.0/17     91.195.159.5                 0     600     100 i
 >>>>> 37.8.192.0/18      91.195.159.5                 0     600     100 i
 >>>> [bgp1]R0_SE600#show bgp route neighbor 91.195.159.10 advertised
 >>>> Address Family: ipv4 unicast
 >>>> BGP table version is 24923504, local router ID is 195.66.73.250
 >>>> Status codes: d damped, h history, > best, i internal
 >>>> Origin codes: i - IGP, e - EGP, ? - incomplete
 >>>>
 >>>> Network            Next Hop                Metric  LocPrf  Weight Path
 >>>>> 31.11.128.0/17     91.195.159.9                 0     600     100 
13000 29314 i
 >>>>> 37.8.192.0/18      91.195.159.9                 0     600     100 
13000 29314 i

Our AS is 13000.
same routes, learned from same peer (external, AS29314) - advertised to 
2 external peers with IDENTICAL route maps...
First one is not showing AS patch at all....

This is in my opinion some kind of a bug...

Regards,
Marcin



> 
> Ron
> 
> Sent from my BlackBerry device on the Rogers Wireless Network
> 
> -----Original Message-----
> From: Marcin Kuczera <marcin at leon.pl>
> Date: Sat, 14 Jan 2012 10:55:05 
> To: Ron Ripley<ripleyron at gmail.com>
> Cc: Ronald Voermans<r.voermans at global-datacenter.nl>; redback-nsp at puck.nether.net<redback-nsp at puck.nether.net>
> Subject: Re: [rbak-nsp] strange BGP printouts...
> 
> Ron Ripley wrote:
>> Hi,
>>
>> The "i" at the end of the AS Path; refers to the origin of an IGP, not iBGP.  Origin codes: i - IGP, e - EGP, ? - incomplete
>>
> 
> So still printouts are faulty, because all routes from printout below 
> are from EGP (external BGP).
> 
> Regards,
> Marcin
> 
> 
>> Ron
>>
>> On 2012-01-13, at 5:58 AM, Ronald Voermans wrote:
>>
>>> Hi Marcin,
>>>
>>> the first one is seen as an internal neighbour (ibgp), hence the 'i' in the path. No as-path is neccessary with ibgp!
>>>
>>> Regards,
>>> Ronald
>>>
>>> Op 13 jan. 2012, om 13:53 heeft Marcin Kuczera het volgende geschreven:
>>>
>>>> look here, I have 2 peers with exacly the same route-maps
>>>>
>>>> Neighbor              AS  MsgRcvd  MsgSent    TblVer  InQ OutQ Rst Up/Down  PfxRcvd/Sent  RstNeeded
>>>> 91.195.159.6       30799       91      102  24923197    0    0   1 01:24:59      4    274        No
>>>> 91.195.159.10     196858    18964    18991  24923213    0    0   2 1w6d      3    272        No
>>>>
>>>>
>>>> Now, look at example of advertised routes:
>>>>
>>>>
>>>> [bgp1]R0_SE600#show bgp route neighbor 91.195.159.6 advertised
>>>> Address Family: ipv4 unicast
>>>> BGP table version is 24923469, local router ID is 195.66.73.250
>>>> Status codes: d damped, h history, > best, i internal
>>>> Origin codes: i - IGP, e - EGP, ? - incomplete
>>>>
>>>> Network            Next Hop                Metric  LocPrf  Weight Path
>>>>> 31.11.128.0/17     91.195.159.5                 0     600     100 i
>>>>> 37.8.192.0/18      91.195.159.5                 0     600     100 i
>>>>> 77.222.224.0/21    91.195.159.5                 0     600     100 i
>>>>> 77.222.232.0/21    91.195.159.5                 0     600     100 i
>>>>> 77.222.240.0/20    91.195.159.5                 0     600     100 i
>>>>> 78.31.136.0/21     91.195.159.5                 0     600     100 i
>>>>> 78.88.0.0/20       91.195.159.5                 0     600     100 i
>>>>> 78.88.16.0/22      91.195.159.5                 0     600     100 i
>>>>> 78.88.20.0/23      91.195.159.5                 0     600     100 i
>>>>> 78.88.22.0/23      91.195.159.5                 0     600     100 i
>>>>> 78.88.24.0/21      91.195.159.5                 0     600     100 i
>>>>> 78.88.32.0/21      91.195.159.5                 0     600     100 i
>>>>> 78.88.40.0/23      91.195.159.5                 0     600     100 i
>>>>> 78.88.43.0/24      91.195.159.5                 0     600     100 i
>>>>> 78.88.48.0/21      91.195.159.5                 0     600     100 i
>>>>> 78.88.56.0/21      91.195.159.5                 0     600     100 i
>>>>> 78.88.64.0/21      91.195.159.5                 0     600     100 i
>>>>> 78.88.72.0/21      91.195.159.5                 0     600     100 i
>>>>> 78.88.80.0/22      91.195.159.5                 0     600     100 i
>>>>> 78.88.84.0/22      91.195.159.5                 0     600     100 i
>>>>> 78.88.88.0/23      91.195.159.5                 0     600     100 i
>>>>> 78.88.90.0/23      91.195.159.5                 0     600     100 i
>>>>> 78.88.92.0/24      91.195.159.5                 0     600     100 i
>>>>> 78.88.93.0/24      91.195.159.5                 0     600     100 i
>>>>> 78.88.96.0/21      91.195.159.5                 0     600     100 i
>>>>> 78.88.106.0/23     91.195.159.5                 0     600     100 i
>>>>> 78.88.108.0/24     91.195.159.5                 0     600     100 i
>>>>> 78.88.109.0/24     91.195.159.5                 0     600     100 i
>>>>> 78.88.110.0/23     91.195.159.5                 0     600     100 i
>>>>> 78.88.112.0/21     91.195.159.5                 0     600     100 i
>>>> [bgp1]R0_SE600#show bgp route neighbor 91.195.159.10 advertised
>>>> Address Family: ipv4 unicast
>>>> BGP table version is 24923504, local router ID is 195.66.73.250
>>>> Status codes: d damped, h history, > best, i internal
>>>> Origin codes: i - IGP, e - EGP, ? - incomplete
>>>>
>>>> Network            Next Hop                Metric  LocPrf  Weight Path
>>>>> 31.11.128.0/17     91.195.159.9                 0     600     100 13000 29314 i
>>>>> 37.8.192.0/18      91.195.159.9                 0     600     100 13000 29314 i
>>>>> 77.222.224.0/21    91.195.159.9                 0     600     100 13000 29314 i
>>>>> 77.222.232.0/21    91.195.159.9                 0     600     100 13000 29314 i
>>>>> 77.222.240.0/20    91.195.159.9                 0     600     100 13000 29314 i
>>>>> 78.31.136.0/21     91.195.159.9                 0     600     100 13000 44124 i
>>>>> 78.88.0.0/20       91.195.159.9                 0     600     100 13000 29314 i
>>>>> 78.88.16.0/22      91.195.159.9                 0     600     100 13000 29314 i
>>>>> 78.88.20.0/23      91.195.159.9                 0     600     100 13000 29314 i
>>>>> 78.88.22.0/23      91.195.159.9                 0     600     100 13000 29314 i
>>>>> 78.88.24.0/21      91.195.159.9                 0     600     100 13000 29314 i
>>>>> 78.88.32.0/21      91.195.159.9                 0     600     100 13000 29314 i
>>>>> 78.88.40.0/23      91.195.159.9                 0     600     100 13000 29314 i
>>>>> 78.88.43.0/24      91.195.159.9                 0     600     100 13000 29314 i
>>>>> 78.88.48.0/21      91.195.159.9                 0     600     100 13000 29314 i
>>>>> 78.88.56.0/21      91.195.159.9                 0     600     100 13000 29314 i
>>>>> 78.88.64.0/21      91.195.159.9                 0     600     100 13000 29314 i
>>>>> 78.88.72.0/21      91.195.159.9                 0     600     100 13000 29314 i
>>>>> 78.88.80.0/22      91.195.159.9                 0     600     100 13000 29314 i
>>>>> 78.88.84.0/22      91.195.159.9                 0     600     100 13000 29314 i
>>>>> 78.88.88.0/23      91.195.159.9                 0     600     100 13000 29314 i
>>>>> 78.88.90.0/23      91.195.159.9                 0     600     100 13000 29314 i
>>>>> 78.88.92.0/24      91.195.159.9                 0     600     100 13000 29314 i
>>>>> 78.88.93.0/24      91.195.159.9                 0     600     100 13000 29314 i
>>>>> 78.88.96.0/21      91.195.159.9                 0     600     100 13000 29314 i
>>>>> 78.88.106.0/23     91.195.159.9                 0     600     100 13000 29314 i
>>>>> 78.88.108.0/24     91.195.159.9                 0     600     100 13000 29314 i
>>>>> 78.88.109.0/24     91.195.159.9                 0     600     100 13000 29314 i
>>>>> 78.88.110.0/23     91.195.159.9                 0     600     100 13000 29314 i
>>>>> 78.88.112.0/21     91.195.159.9                 0     600     100 13000 29314 i
>>>> [bgp1]R0_SE600#
>>>>
>>>>
>>>> the first one is strange, because it looks like AS path is missing.
>>>> Is it a random bug ?
>>>>
>>>> Regards,
>>>> Marcin
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