[rbak-nsp] strange BGP printouts...

Marcin Kuczera marcin at leon.pl
Mon Jan 16 09:04:02 EST 2012


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.
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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