Advanced
Mailing List Archive

Mailing List Archive

  1. Home >
  2. Quagga>
  3. Users
BGP: Understanding of "show ip bgp"
rhentsch at barracuda
Nov 12, 2012, 11:47 PM
Post #1 of 11 (6884 views)
Permalink
Dear Quagga mailing list,

I use quagga's BGP deamon for propagating routes in a newtork.

Now I'm a little bit confused about the output of "sh ip bgp" in vtysh.

I can see there an "i" or a "?" as origin code for every route, no matter if it was learned from a peer in my AS or from a peer in another AS.

So my question is: When will I see an "e" for "EGP" there?

As an example, here is my configuration:

Route 192.168.150.0/24 is learned via AS100. Box LE-HQ1 is in AS 200.

LE-HQ1# sh ip bgp sum

BGP router identifier 10.5.129.100, local AS number 200

RIB entries 15, using 840 bytes of memory

Peers 1, using 2480 bytes of memory

Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd

10.6.129.39 4 100 3698 3707 0 0 0 16:30:41 5

Total number of neighbors 1

.

LE-HQ1# sh ip bgp

BGP table version is 0, local router ID is 10.5.129.100

Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,

r RIB-failure, S Stale, R Removed

Origin codes: i - IGP, e - EGP, ? - incomplete

Network Next Hop Metric LocPrf Weight Path

*> 10.5.129.96/28 0.0.0.0 0 32768 ?

*> 10.6.129.0/24 10.6.129.39 0 0 100 ?

*> 25.25.25.0/24 10.6.129.39 0 0 100 i

*> 192.168.125.0 10.6.129.39 0 0 100 i

*> 192.168.150.0 10.6.129.39 0 0 100 i

*> 192.168.200.0 0.0.0.0 0 32768 i

*> 192.168.201.0 10.6.129.39 0 0 100 i

*> 192.168.225.0 0.0.0.0 0 32768 i

Total number of prefixes 8

LE-HQ1#

Why is the origin of 192.168.150.0 "i" and not "e"?

Thank you very much for your help!

Best regards, Robert Hentsch



Barracuda Networks AG
Vorsitzender des Aufsichtsrates/ Chairman of the supervisory board: Dr. Klaus Perktold
Vorstand/ Executive Board: Dr. Wieland Alge, Mag. Guenter Klausner
Sitz der Gesellschaft/ Registered office: 6020 Innsbruck, Austria
Handelsgericht Innsbruck Firmenbuch/ Registration Number: 184392s
UID-Nr/ VAT Number: ATU47509003



Diese Nachricht und allfaellige angehaengte Dokumente sind vertraulich und nur fuer den/die Adressaten bestimmt. Sollten Sie nicht der beabsichtigte Adressat sein, ist jede Offenlegung, Weiterleitung oder sonstige Verwendung dieser Information nicht gestattet. In diesem Fall bitten wir, den Absender zu verstaendigen und die Information zu vernichten. Fuer Uebermittlungsfehler oder sonstige Irrtuemer bei Uebermittlung besteht keine Haftung.



This message and any attached files are confidential and intended solely for the addressee(s). Any publication, transmission or other use of the information by a person or entity other than the intended addressee is prohibited. If you receive this in error please contact the sender and delete the material. The sender does not accept liability for any errors or omissions as a result of the transmission.



'Like' us on Facebook for exclusive content and other resources on all Barracuda Networks solutions.
Visit http://barracudanetworks.com/facebook
Re: BGP: Understanding of "show ip bgp" [ In reply to ]
equinox at diac24
Nov 15, 2012, 4:45 PM
Post #2 of 11 (6778 views)
Permalink
On Tue, Nov 13, 2012 at 08:47:25AM +0100, Robert Hentsch wrote:
> I can see there an "i" or a "?" as origin code for every route, no matter if it was learned from a peer in my AS or from a peer in another AS.
>
> So my question is: When will I see an "e" for "EGP" there?

On the real internet: never, hopefully.

The origin indicator (i/?/e) refers to where the last BGP participant /
Origin AS pulled the information from. It's basically an extension of
the AS-path. "This route passed through these ASNs, and before entering
into BGP it came from an IGP/EGP/Unknown." That's why it is behind the
AS-path in output.

This was designed for transition from other EGPs towards BGP, cf.
http://en.wikipedia.org/wiki/Exterior_Gateway_Protocol

If you see "Origin EGP" on the internet nowadays, that's someone
fiddling with knobs on their router that they should better leave alone.
If you see "Origin Unknown", that's most likely a problem with IGP
routing at the originator.

Cheers,


-David
_______________________________________________
Quagga-users mailing list
Quagga-users@lists.quagga.net
http://lists.quagga.net/mailman/listinfo/quagga-users
Re: BGP: Understanding of "show ip bgp" [ In reply to ]
banyan at rootong
Nov 15, 2012, 6:47 PM
Post #3 of 11 (6759 views)
Permalink
It's just quagga following what cisco does. The route comes out from
"network" command will be showing as in "i" as the IGP.

------------
Banyan He
Blog: http://www.rootong.com
Email: banyan@rootong.com

On 2012-11-16 8:45 AM, David Lamparter wrote:
> On Tue, Nov 13, 2012 at 08:47:25AM +0100, Robert Hentsch wrote:
>> I can see there an "i" or a "?" as origin code for every route, no matter if it was learned from a peer in my AS or from a peer in another AS.
>>
>> So my question is: When will I see an "e" for "EGP" there?
> On the real internet: never, hopefully.
>
> The origin indicator (i/?/e) refers to where the last BGP participant /
> Origin AS pulled the information from. It's basically an extension of
> the AS-path. "This route passed through these ASNs, and before entering
> into BGP it came from an IGP/EGP/Unknown." That's why it is behind the
> AS-path in output.
>
> This was designed for transition from other EGPs towards BGP, cf.
> http://en.wikipedia.org/wiki/Exterior_Gateway_Protocol
>
> If you see "Origin EGP" on the internet nowadays, that's someone
> fiddling with knobs on their router that they should better leave alone.
> If you see "Origin Unknown", that's most likely a problem with IGP
> routing at the originator.
>
> Cheers,
>
>
> -David
> _______________________________________________
> Quagga-users mailing list
> Quagga-users@lists.quagga.net
> http://lists.quagga.net/mailman/listinfo/quagga-users
>

_______________________________________________
Quagga-users mailing list
Quagga-users@lists.quagga.net
http://lists.quagga.net/mailman/listinfo/quagga-users
Re: BGP: Understanding of "show ip bgp" [ In reply to ]
alex at alex
Nov 16, 2012, 2:39 AM
Post #4 of 11 (6760 views)
Permalink
On 16 Nov 2012, at 00:45, David Lamparter wrote:

> On Tue, Nov 13, 2012 at 08:47:25AM +0100, Robert Hentsch wrote:
>> I can see there an "i" or a "?" as origin code for every route, no matter if it was learned from a peer in my AS or from a peer in another AS.
>>
>> So my question is: When will I see an "e" for "EGP" there?
>
> On the real internet: never, hopefully.

Incorrect. egp origin is set occasionally to influence route selection, being the route comparison step after AS path length. EGP itself is never used these days, but that doesn't mean you'll never see an 'e'. See 'set origin' in route maps.

--
Alex Bligh





_______________________________________________
Quagga-users mailing list
Quagga-users@lists.quagga.net
http://lists.quagga.net/mailman/listinfo/quagga-users
Re: BGP: Understanding of "show ip bgp" [ In reply to ]
equinox at diac24
Nov 16, 2012, 2:51 AM
Post #5 of 11 (6766 views)
Permalink
On Fri, Nov 16, 2012 at 10:39:28AM +0000, Alex Bligh wrote:
>
> On 16 Nov 2012, at 00:45, David Lamparter wrote:
>
> > On Tue, Nov 13, 2012 at 08:47:25AM +0100, Robert Hentsch wrote:
> >> I can see there an "i" or a "?" as origin code for every route, no matter if it was learned from a peer in my AS or from a peer in another AS.
> >>
> >> So my question is: When will I see an "e" for "EGP" there?
> >
> > On the real internet: never, hopefully.
>
> Incorrect. egp origin is set occasionally to influence route
> selection, being the route comparison step after AS path length. EGP
> itself is never used these days, but that doesn't mean you'll never
> see an 'e'. See 'set origin' in route maps.

OK then :) - the explanation is still true, origin type is really the
"last entry" on the AS path. Fits in with the comparison algorithm too.

(Out of curiosity, can someone check a fulltable for the number of "e"
routes? I could probably look it up from the RIPE dumps or so, but it's
faster if someone just does a "show ip bgp | incl e"...)


-David
_______________________________________________
Quagga-users mailing list
Quagga-users@lists.quagga.net
http://lists.quagga.net/mailman/listinfo/quagga-users
Re: BGP: Understanding of "show ip bgp" [ In reply to ]
matthew at walster
Nov 16, 2012, 4:35 AM
Post #6 of 11 (6766 views)
Permalink
On 16 November 2012 00:45, David Lamparter <equinox@diac24.net> wrote:

> On Tue, Nov 13, 2012 at 08:47:25AM +0100, Robert Hentsch wrote:
> > I can see there an "i" or a "?" as origin code for every route, no
> matter if it was learned from a peer in my AS or from a peer in another AS.
> >
> > So my question is: When will I see an "e" for "EGP" there?
>
> On the real internet: never, hopefully.
>

I was actually corrected on this the other day. "e" just means "Exterior"
in that it was redistributed from an origin of external source.

https://supportforums.cisco.com/thread/208363

I must admit that before last week, I thought the same as you.

Matthew Walster
Re: BGP: Understanding of "show ip bgp" [ In reply to ]
nick at inex
Nov 16, 2012, 5:07 AM
Post #7 of 11 (6762 views)
Permalink
On 16/11/2012 10:51, David Lamparter wrote:
> (Out of curiosity, can someone check a fulltable for the number of "e"
> routes?

Many transit providers meddle with the origin so that they can apply a
small amount of undue influence to their customers' best path algorithm.
BGP origin is considered next in line after as path length, so if your
competitor is announcing prefixes with origin=egp, then if your path length
is the same, you can snitch that traffic by announcing the same prefix with
origin=igp.

I suspect this accounts for a couple of percent difference in terms of 95th
percentile traffic => a couple of % revenue => a couple of % net profit.
I.e. it's irresistible for transit providers to do it.

As a matter of policy, I strip off the origin on all transit / peering links.

Nick

_______________________________________________
Quagga-users mailing list
Quagga-users@lists.quagga.net
http://lists.quagga.net/mailman/listinfo/quagga-users
Re: BGP: Understanding of "show ip bgp" [ In reply to ]
nick at inex
Nov 16, 2012, 5:12 AM
Post #8 of 11 (6771 views)
Permalink
On 16/11/2012 13:07, Nick Hilliard wrote:
> competitor is announcing prefixes with origin=egp, then if your path length
> is the same, you can snitch that traffic by announcing the same prefix with
> origin=igp.

in particular, origin comes before testing next-hop IGP metric. I.e. it may
override your local hot potato policy.

Nick

_______________________________________________
Quagga-users mailing list
Quagga-users@lists.quagga.net
http://lists.quagga.net/mailman/listinfo/quagga-users
Re: BGP: Understanding of "show ip bgp" [ In reply to ]
powell at rmu
Nov 17, 2012, 5:49 AM
Post #9 of 11 (6765 views)
Permalink
The "next hop" in the routing, once eBGP delivers the message to the AS, is
internal within the AS. Therefore the last hop is "i." Sample path: 64502
64501 i
As we list at: http://www.infroref.org/i6230vlabnet7-BGP.htm


Valerie
--
Valerie J H Powell RT(R) PhD
University Professor, Computer & Information Systems
Project on Clinical Data Integration (CDI)
Robert Morris University
6001 University Boulevard
Moon Township, PA 15108-1189 USA
+1-412-397-6452 (Moon)
Office (Moon): Wheatley Center, Room 324
Re: BGP: Understanding of "show ip bgp" [ In reply to ]
rickp at rossfell
Nov 18, 2012, 2:21 AM
Post #10 of 11 (6750 views)
Permalink
--On 16 November 2012 11:51:41 +0100 David Lamparter
<equinox@diac24.net> wrote:

> (Out of curiosity, can someone check a fulltable for the number of "e"
> routes? I could probably look it up from the RIPE dumps or so, but
> it's faster if someone just does a "show ip bgp | incl e"...)

Just from a single feed:

(bgpr@127.0.0.1)132> EGPSearch = fun(X, A) -> case lists:nth(1,
bgp_protocol:attribute_find(origin, X)) of #bgp_attribute_origin{type
= egp} -> A+1; _ -> A end end.
#Fun<erl_eval.12.82930912>

(bgpr@127.0.0.1)133> length(Attrs).
70891
(bgpr@127.0.0.1)134> lists:foldl(EGPSearch, 0, Attrs).
254
(bgpr@127.0.0.1)144> lists:foldl(IncompleteSearch, 0, Attrs).
3840
(bgpr@127.0.0.1)145> lists:foldl(IGPSearch, 0, Attrs).
66797


So 254 occurances of egp out of a shade over 70k attributes.

Rick
_______________________________________________
Quagga-users mailing list
Quagga-users@lists.quagga.net
http://lists.quagga.net/mailman/listinfo/quagga-users
Re: BGP: Understanding of "show ip bgp" [ In reply to ]
if at xip
Nov 18, 2012, 4:41 PM
Post #11 of 11 (6758 views)
Permalink
Dear Valerie,

show ip bgp
BGP table version is 0, local router ID is x.x.x.x
Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal,
r RIB-failure, S Stale, R Removed
Origin codes: i - IGP, e - EGP, ? - incomplete
^^^^^^^^

Details:
http://www.cisco.com/en/US/docs/ios/iproute_bgp/command/reference/irg_bgp5.html#wp1156281

Kind regards,
Ingo Flaschberger


Am 17.11.2012 14:49, schrieb Valerie Powell:
> The "next hop" in the routing, once eBGP delivers the message to the
> AS, is internal within the AS. Therefore the last hop is "i." Sample
> path: 64502 64501 i
> As we list at: http://www.infroref.org/i6230vlabnet7-BGP.htm
>
>
> Valerie
> --
> Valerie J H Powell RT(R) PhD
> University Professor, Computer & Information Systems
> Project on Clinical Data Integration (CDI)
> Robert Morris University
> 6001 University Boulevard
> Moon Township, PA 15108-1189 USA
> +1-412-397-6452 (Moon)
> Office (Moon): Wheatley Center, Room 324
>
>
> _______________________________________________
> Quagga-users mailing list
> Quagga-users@lists.quagga.net
> http://lists.quagga.net/mailman/listinfo/quagga-users


--

Mit freundlichen Grüßen,

With best regards,

Ingo Flaschberger

Geschäftsleitung

---

Beschreibung: Beschreibung: Beschreibung: logo_email2

*Besondere Ansprüche. Individuelle Lösungen.
Particular demands. **Individual solutions.***

crossip communications gmbh

A-1020 Wien, Wohlmutstrasse 27

Sitz der Gesellschaft: 1020 Wien, Österreich

Firmenbuchgericht: Handelsgericht Wien, FN 269698 s,
Umsatzsteueridentifikationsnummer (UID): ATU62080367

Haftungsausschluss / Disclaimer:
_http://www.crossip.net/de/legal/haftungsausschluss-disclaimer_

Attached Files:

©2024 GT.net. A Gossamer Threads company.
5th Floor, 455 Granville St., Vancouver, BC V6C 1T1, Canada | Legal