[rbak-nsp] strange BGP printouts...
Tomas Lynch
tomas.lynch at gmail.com
Mon Jan 16 10:08:58 EST 2012
On Mon, Jan 16, 2012 at 11:04 AM, Marcin Kuczera <marcin at leon.pl> wrote:
> Tomas Lynch wrote:
>>
>> Marcin,
>>
>> Actually the strange thing here is that for the second peer the
>> adevetised routes are showing your ASN in the path; this shouldn't be
>> happen at all. Do you have anywhere the "accept own as " command?
>> (don't remember the exact name of the command but you get the idea)
>>
>> I think you have some kind of loop somewhere. Can you provide the
>> "show bgp route 31.11.128.0/17" output please?
>
>
> Look, this is not "received" but "advertised".
> In advertised it makes sense - so that I see what the other side will see.
In BGP advertisements you shouldn't see your own AS in the path and
that is what is happening with the second peer:
31.11.128.0/17 31.11.128.0/17 91.195.159.9 0 600 100
13000 29314 i
The AS path here is 13000 29314. When your peer does the show bgp,
they will see the as path as 13000 13000 29314. That's why I'm
suggesting that there is a loop somewhere
TL
> Prevention of loops is a feature of BGP protocol itself, maybe can be
> ommited with command, but I don't do it.
>
> Here is a printout:
>
> [bgp1]R0_SE600#show bgp route 31.11.128.0/17
> BGP ipv4 unicast routing table entry: 31.11.128.0/17, version 20274522
> Paths: total 7, best path count 1, best peer 93.105.7.241
> Advertised to non-peer-group peers: 7
> 91.195.159.6 91.195.159.10 91.195.159.30 91.195.159.46 91.195.159.138
> 91.195.159.230 195.66.73.245
>
> 12968 29314 29314 29314
> Nexthop 93.159.57.141 (0), peer 93.159.57.141 (93.159.57.8), AS 12968
> Origin IGP, localpref 499, med 0, weight 100, external
> Community: 13000:9001
>
>
> 15744 13293 1299 3356 29314
> Nexthop 212.106.159.142 (0), peer 212.106.159.142 (83.230.95.254), AS 15744
> Origin IGP, localpref 200, med 0, weight 100, external
> Community: 13000:9001
>
>
> 24724 29314
> Nexthop 193.111.38.97 (0), peer 193.111.38.97 (193.111.37.1), AS 24724
> Origin IGP, localpref 200, med 0, weight 100, external
> Community: 29314:999
>
>
> 29314
> Nexthop 93.105.7.241 (0), peer 93.105.7.241 (172.17.17.251), AS 29314
> Origin IGP, localpref 600, med 0, weight 100, external, best
> Community: 13000:9998 13000:9999
>
>
> 29314 29314 29314
> Nexthop 195.182.218.187 (0), peer 195.182.218.99 (195.182.218.99), AS 8545
> Origin IGP, localpref 501, med 0, weight 100, external
> Community: 8545:29314 8545:65120 29314:999
>
>
> 29314 29314 29314
> Nexthop 195.182.218.187 (0), peer 195.182.218.100 (195.182.218.100), AS
> 8545
> Origin IGP, localpref 501, med 0, weight 100, external
> Community: 8545:29314 8545:65120 29314:999
>
>
> 50607 29314
> Nexthop 195.191.171.169 (0), peer 195.191.171.169 (195.191.171.4), AS 50607
> Origin IGP, localpref 220, med 0, weight 100, external
> Community: 13000:9999
>
> [bgp1]R0_SE600#
>
> Regards,
> Marcin
>
>
>
>>
>> Tomas Lynch
>>
>> On Sun, Jan 15, 2012 at 9:34 AM, Marcin Kuczera <marcin at leon.pl> wrote:
>>>
>>> Christopher O'Shea wrote:
>>>>
>>>> Hi Marcin,
>>>>
>>>> What does router map look like.
>>>
>>>
>>> !
>>> route-map direct-peering-rix-in permit 10
>>> set community 13000:9998 13000:9999
>>> set local-preference 600
>>> !
>>> route-map direct-peering-rix-out permit 5
>>> match as-path-list AS13000-only
>>> route-map direct-peering-rix-out permit 10
>>> match community-list kdi-full-bgp
>>> route-map direct-peering-rix-out permit 11
>>> match community-list rix-peering
>>> !
>>>
>>> !
>>> community-list kdi-full-bgp
>>> seq 10 permit 13000:9900
>>> !
>>> community-list rix-peering
>>> seq 10 permit 13000:9998
>>> !
>>>
>>> !
>>> as-path-list AS13000-only
>>> seq 10 permit ^$
>>> !
>>>
>>>
>>> Regards,
>>> Marcin
>>>
>>>
>>>
>>>> Chris O'Shea
>>>>
>>>>
>>>>
>>>> On Sun, Jan 15, 2012 at 10:24 AM, Marcin Kuczera <marcin at leon.pl
>>>> <mailto:marcin at leon.pl>> wrote:
>>>>
>>>>
>>>> ripleyron at gmail.com <mailto: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 <http://31.11.128.0/17> 91.195.159.5
>>>> 0 600 100 i
>>>> >>>>> 37.8.192.0/18 <http://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 <http://31.11.128.0/17> 91.195.159.9
>>>> 0 600 100 13000 29314 i
>>>> >>>>> 37.8.192.0/18 <http://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 <mailto:marcin at leon.pl>>
>>>> Date: Sat, 14 Jan 2012 10:55:05 To: Ron
>>>> Ripley<ripleyron at gmail.com <mailto:ripleyron at gmail.com>>
>>>> Cc: Ronald Voermans<r.voermans at global-__datacenter.nl
>>>> <mailto:r.voermans at global-datacenter.nl>>;
>>>> redback-nsp at puck.nether.net
>>>> <mailto:redback-nsp at puck.nether.net><re__dback-nsp at puck.nether.net
>>>> <mailto: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 <http://31.11.128.0/17>
>>>> 91.195.159.5 0 600 100 i
>>>> 37.8.192.0/18 <http://37.8.192.0/18>
>>>> 91.195.159.5 0 600 100 i
>>>> 77.222.224.0/21 <http://77.222.224.0/21>
>>>> 91.195.159.5 0 600 100 i
>>>> 77.222.232.0/21 <http://77.222.232.0/21>
>>>> 91.195.159.5 0 600 100 i
>>>> 77.222.240.0/20 <http://77.222.240.0/20>
>>>> 91.195.159.5 0 600 100 i
>>>> 78.31.136.0/21 <http://78.31.136.0/21>
>>>> 91.195.159.5 0 600 100 i
>>>> 78.88.0.0/20 <http://78.88.0.0/20>
>>>> 91.195.159.5 0 600 100 i
>>>> 78.88.16.0/22 <http://78.88.16.0/22>
>>>> 91.195.159.5 0 600 100 i
>>>> 78.88.20.0/23 <http://78.88.20.0/23>
>>>> 91.195.159.5 0 600 100 i
>>>> 78.88.22.0/23 <http://78.88.22.0/23>
>>>> 91.195.159.5 0 600 100 i
>>>> 78.88.24.0/21 <http://78.88.24.0/21>
>>>> 91.195.159.5 0 600 100 i
>>>> 78.88.32.0/21 <http://78.88.32.0/21>
>>>> 91.195.159.5 0 600 100 i
>>>> 78.88.40.0/23 <http://78.88.40.0/23>
>>>> 91.195.159.5 0 600 100 i
>>>> 78.88.43.0/24 <http://78.88.43.0/24>
>>>> 91.195.159.5 0 600 100 i
>>>> 78.88.48.0/21 <http://78.88.48.0/21>
>>>> 91.195.159.5 0 600 100 i
>>>> 78.88.56.0/21 <http://78.88.56.0/21>
>>>> 91.195.159.5 0 600 100 i
>>>> 78.88.64.0/21 <http://78.88.64.0/21>
>>>> 91.195.159.5 0 600 100 i
>>>> 78.88.72.0/21 <http://78.88.72.0/21>
>>>> 91.195.159.5 0 600 100 i
>>>> 78.88.80.0/22 <http://78.88.80.0/22>
>>>> 91.195.159.5 0 600 100 i
>>>> 78.88.84.0/22 <http://78.88.84.0/22>
>>>> 91.195.159.5 0 600 100 i
>>>> 78.88.88.0/23 <http://78.88.88.0/23>
>>>> 91.195.159.5 0 600 100 i
>>>> 78.88.90.0/23 <http://78.88.90.0/23>
>>>> 91.195.159.5 0 600 100 i
>>>> 78.88.92.0/24 <http://78.88.92.0/24>
>>>> 91.195.159.5 0 600 100 i
>>>> 78.88.93.0/24 <http://78.88.93.0/24>
>>>> 91.195.159.5 0 600 100 i
>>>> 78.88.96.0/21 <http://78.88.96.0/21>
>>>> 91.195.159.5 0 600 100 i
>>>> 78.88.106.0/23 <http://78.88.106.0/23>
>>>> 91.195.159.5 0 600 100 i
>>>> 78.88.108.0/24 <http://78.88.108.0/24>
>>>> 91.195.159.5 0 600 100 i
>>>> 78.88.109.0/24 <http://78.88.109.0/24>
>>>> 91.195.159.5 0 600 100 i
>>>> 78.88.110.0/23 <http://78.88.110.0/23>
>>>> 91.195.159.5 0 600 100 i
>>>> 78.88.112.0/21 <http://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 <http://31.11.128.0/17>
>>>> 91.195.159.9 0 600 100
>>>> 13000 29314 i
>>>> 37.8.192.0/18 <http://37.8.192.0/18>
>>>> 91.195.159.9 0 600 100
>>>> 13000 29314 i
>>>> 77.222.224.0/21 <http://77.222.224.0/21>
>>>> 91.195.159.9 0 600 100
>>>> 13000 29314 i
>>>> 77.222.232.0/21 <http://77.222.232.0/21>
>>>> 91.195.159.9 0 600 100
>>>> 13000 29314 i
>>>> 77.222.240.0/20 <http://77.222.240.0/20>
>>>> 91.195.159.9 0 600 100
>>>> 13000 29314 i
>>>> 78.31.136.0/21 <http://78.31.136.0/21>
>>>> 91.195.159.9 0 600 100
>>>> 13000 44124 i
>>>> 78.88.0.0/20 <http://78.88.0.0/20>
>>>> 91.195.159.9 0 600 100
>>>> 13000 29314 i
>>>> 78.88.16.0/22 <http://78.88.16.0/22>
>>>> 91.195.159.9 0 600 100
>>>> 13000 29314 i
>>>> 78.88.20.0/23 <http://78.88.20.0/23>
>>>> 91.195.159.9 0 600 100
>>>> 13000 29314 i
>>>> 78.88.22.0/23 <http://78.88.22.0/23>
>>>> 91.195.159.9 0 600 100
>>>> 13000 29314 i
>>>> 78.88.24.0/21 <http://78.88.24.0/21>
>>>> 91.195.159.9 0 600 100
>>>> 13000 29314 i
>>>> 78.88.32.0/21 <http://78.88.32.0/21>
>>>> 91.195.159.9 0 600 100
>>>> 13000 29314 i
>>>> 78.88.40.0/23 <http://78.88.40.0/23>
>>>> 91.195.159.9 0 600 100
>>>> 13000 29314 i
>>>> 78.88.43.0/24 <http://78.88.43.0/24>
>>>> 91.195.159.9 0 600 100
>>>> 13000 29314 i
>>>> 78.88.48.0/21 <http://78.88.48.0/21>
>>>> 91.195.159.9 0 600 100
>>>> 13000 29314 i
>>>> 78.88.56.0/21 <http://78.88.56.0/21>
>>>> 91.195.159.9 0 600 100
>>>> 13000 29314 i
>>>> 78.88.64.0/21 <http://78.88.64.0/21>
>>>> 91.195.159.9 0 600 100
>>>> 13000 29314 i
>>>> 78.88.72.0/21 <http://78.88.72.0/21>
>>>> 91.195.159.9 0 600 100
>>>> 13000 29314 i
>>>> 78.88.80.0/22 <http://78.88.80.0/22>
>>>> 91.195.159.9 0 600 100
>>>> 13000 29314 i
>>>> 78.88.84.0/22 <http://78.88.84.0/22>
>>>> 91.195.159.9 0 600 100
>>>> 13000 29314 i
>>>> 78.88.88.0/23 <http://78.88.88.0/23>
>>>> 91.195.159.9 0 600 100
>>>> 13000 29314 i
>>>> 78.88.90.0/23 <http://78.88.90.0/23>
>>>> 91.195.159.9 0 600 100
>>>> 13000 29314 i
>>>> 78.88.92.0/24 <http://78.88.92.0/24>
>>>> 91.195.159.9 0 600 100
>>>> 13000 29314 i
>>>> 78.88.93.0/24 <http://78.88.93.0/24>
>>>> 91.195.159.9 0 600 100
>>>> 13000 29314 i
>>>> 78.88.96.0/21 <http://78.88.96.0/21>
>>>> 91.195.159.9 0 600 100
>>>> 13000 29314 i
>>>> 78.88.106.0/23 <http://78.88.106.0/23>
>>>> 91.195.159.9 0 600 100
>>>> 13000 29314 i
>>>> 78.88.108.0/24 <http://78.88.108.0/24>
>>>> 91.195.159.9 0 600 100
>>>> 13000 29314 i
>>>> 78.88.109.0/24 <http://78.88.109.0/24>
>>>> 91.195.159.9 0 600 100
>>>> 13000 29314 i
>>>> 78.88.110.0/23 <http://78.88.110.0/23>
>>>> 91.195.159.9 0 600 100
>>>> 13000 29314 i
>>>> 78.88.112.0/21 <http://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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