Re: Possible bug ? Re: 4.7 Release - bgpd not passing IBGP routes

[a b]

Thanks for the heads up Claudio, will look into it a bit more in light of your
comments.

Re: Possible bug ? Re: 4.7 Release - bgpd not passing IBGP routes

[Claudio Jeker]

On Sun, May 30, 2010 at 10:38:01PM +, a b wrote:
 (1) With set localpref 500 on EBGP session on BSD02
 
 bgpctl sh rib on BSD01 :
 I* 0.0.0.0/0172.16.99.254500065432i
 *   0.0.0.0/0172.16.99.254100065432i
 
 bgpctl sh rib on BSD02 :
 *  0.0.0.0/0172.16.99.254500065432i
 

This looks right. BSD02 is propegating the route to BSD01 and BSD01
selects that one as more prefered over the non iBGP route.

 (2) With no localpref set on EBGP session on BGP02
 
 bgpctl sh rib on BSD01 :
 * 0.0.0.0/0172.16.99.254100065432i
 I* 0.0.0.0/0172.16.99.254100065432i
 
 bgpctl sh rib on BSD02 :
 * 0.0.0.0/0172.16.99.254100065432i
 I* 0.0.0.0/0172.16.99.254100065432i
 

Again correct, both routers select the eBGP route since the prefixes have
the same metrics until the tiebreaker reaches the ebgp vs ibgp check. In
both cases the router select the eBGP route and propagate that route to
the other iBGP router.

 (3) With set localpref 25 on EBGP session on BSD02
 
 bgpctl sh rib on BSD01 :
 *0.0.0.0/0172.16.99.254 100065432i
 
 bgpctl sh rib on BSD02 :
 I*  0.0.0.0/0  172.16.99.254100065432i
 *0.0.0.0/0  172.16.99.25425 065432i
 

Again everything is fine. BSD01 selects the eBGP route and propagets that
route as iBGP route the BSD02 where that route is more prefered because of
the higher localpref.

Note, only the active route is redistributed and over iBGP sessions only
the active routes that are not internal are redistributed. That is the
reason why in case 1 and 3 only one router ends up with both routes.

PS: please fix your mailclient. It is almost impossible to read the mails
because of the insane linewrapping.
-- 
:wq Claudio

Re: Possible bug ? Re: 4.7 Release - bgpd not passing IBGP routes

[Insan Praja SW]

Hi,
On Sun, 30 May 2010 02:34:12 +0700, a b obsdmisc...@yahoo.co.uk wrote:


Hi,

Further to my earlier email, additional experimentation shows that
removal of set localpref from my config file on BSD02 allows full mesh  
IBGP
to correctly occur.  Reinsertion of set localpref makes the issue  
originally

reported reappear.



By setting received prefixes to localpref 400, it would be preferable to  
the router thus made other similar prefixes with lower localpref  
unselected. But, yes, it should appeared on RIB. Please show us bgpctl sh  
rib output from all routers. And, if I'm not mistaken, if there are  
prefixes with the same metrics comes from both eBGP and iBGP, prefixes  
from eBGP peers will be chosen.


HTH,



--
insandotpraja(at)gmaildotcom

Re: Possible bug ? Re: 4.7 Release - bgpd not passing IBGP routes

[a b]

(1) With set localpref 500 on EBGP session on BSD02

bgpctl sh rib on
BSD01 :
I*0.0.0.0/0172.16.99.254500065432i
*
0.0.0.0/0172.16.99.254100065432i

bgpctl sh rib on BSD02
:
*0.0.0.0/0172.16.99.254500065432i

(2) With no
localpref set on EBGP session on BGP02

bgpctl sh rib on BSD01 :
*
0.0.0.0/0172.16.99.254100065432i
I*0.0.0.0/0
172.16.99.254100065432i

bgpctl sh rib on BSD02 :
*
0.0.0.0/0172.16.99.254100065432i
I*0.0.0.0/0
172.16.99.254100065432i

(3) With set localpref 25 on EBGP
session on BSD02

bgpctl sh rib on BSD01 :
*0.0.0.0/0172.16.99.254
100065432i

bgpctl sh rib on BSD02 :
I*0.0.0.0/0
172.16.99.254100065432i
*0.0.0.0/0172.16.99.25425
065432i

Possible bug ? Re: 4.7 Release - bgpd not passing IBGP routes

[a b]

Hi,

Further to my earlier email, additional experimentation shows that
removal of set localpref from my config file on BSD02 allows full mesh IBGP
to correctly occur.  Reinsertion of set localpref makes the issue originally
reported reappear.