[j-nsp] General BGP question, single asn multi location

[Alexandre Snarskii]

On Wed, Jul 25, 2012 at 10:41:56AM +0200, Daniel Roesen wrote:
> On Wed, Jul 25, 2012 at 01:32:50AM -0700, Morgan McLean wrote:
> > So I have a single ASN and two sites that do not peer directly with each
> > other, but have eBGP with providers.
> > 
> > Site A takes full routes, advertises a /24
> > Site B takes defaults only, advertises a /24
> > 
> > I notice I do not get the route advertised at site B by any of my providers
> > at site A. Is this due to a general misconfiguration of BGP? Are they not
> > sending me routes from my own ASN?
> 
> You're hitting BGP loop prevention by means of AS_PATH.
> 
> Solution:
> http://www.juniper.net/techpubs/en_US/junos11.4/topics/reference/configuration-statement/loops-edit-protocols-bgp-family.html
> 
> "loops 2" is your friend.

and one more point - the same loop prevention technique may be employed
at your provider's routers (juniper by default does not announce routes
learned from ASn to the peers in the same ASn). 

Solution: 

http://www.juniper.net/techpubs/software/junos/junos94/swconfig-routing/disabling-suppression-of-route-advertisements.html

-- 
In theory, there is no difference between theory and practice. 
But, in practice, there is.