[c-nsp] BGP conditional advertisemet - NON-EXIST route map'saccess-list problem

[RPhookun at lecg.com]

One gotcha I ran into sometime ago -  on 12.4 T

the  neighbor 192.168.100.1 advertise-map ADVERTISE non-exist-map 
NON-EXIST has to be configured in the address-family ipv4 

conf t
router bgp 10
address-family ipv4
neighbor 192.168.100.1 advertise-map ADVERTISE non-exist-map NON-EXIST
exit-address-family

Not sure if this is your case. 

can you include the output of - 

sh ip bgp neigh x.x.x.x
sh ip bgp neigh x.x.x.x advertised routes?

Regards,
./Randy






Burak Dikici <bdikici at gmail.com> 
Sent by: cisco-nsp-bounces at puck.nether.net
03/15/2009 02:21 PM

To
RPhookun at lecg.com
cc
Ivan Pepelnjak <ip at ioshints.info>, cisco-nsp-bounces at puck.nether.net, 
cisco-nsp at puck.nether.net
Subject
Re: [c-nsp] BGP conditional advertisemet - NON-EXIST route 
map'saccess-list problem






 I have made a change on the lab with the commands which are written below 
,
but ISP-2 still getting my announcment. No success...


ip as-path access-list 1 permit ^200  (ISP-1 AS number)

ip prefix-list AS200-track seq 5 permit 192.168.200.0/24 (subnet
between multihoming router and ISP-1 router)

route-map NON-EXIST permit 10
 match ip address prefix-list AS200-track
 match as-path 1

router bgp 10
 neighbor 192.168.100.1 advertise-map ADVERTISE non-exist-map NON-EXIST








On Sun, Mar 15, 2009 at 11:03 PM, <RPhookun at lecg.com> wrote:

>
> I agree with Ivan in that the tracked prefix  in the Non-Exist-Map 
should
> be the ISP-1 infrastructure address because in its absence you wouldn't 
be
> receiving any other routes from ISP-1
> However, the match of the tracked prefix is from the BGP table *not* the 
IP
> routing table and "match-as-path" can be very relevant in some 
topologies
> and its absence in the Non-Exist-Map can cause the conditional 
advertisement
> feature to break.
>
> Cisco has an excellent example - "Configuring and Verifying the 
Conditional
> Advertisement Feature"
>
> ./Randy
>
>
>
>
>
>   *"Ivan Pepelnjak" <ip at ioshints.info>*
> Sent by: cisco-nsp-bounces at puck.nether.net
>
> 03/15/2009 12:48 PM
>    To
>  "'Burak Dikici'" <bdikici at gmail.com>
>  cc
>   cisco-nsp at puck.nether.net  Subject
> Re: [c-nsp] BGP conditional advertisemet - NON-EXIST route
>  map'saccess-list problem
>
>
>
>
>
>  That's the problem everyone has with the NON-EXIST-MAP :) Usually the 
IP
> prefix used to address the ISP-1 infrastructure is the best bet.
>
> The "match as-path" statement in the NON-EXIST-MAP is irrelevant (unless
> I'm
> totally wrong about the match being made with the routes in the IP 
routing
> table :).
>
> Ivan
>
>
>  _____
>
> From: Burak Dikici [mailto:bdikici at gmail.com]
> Sent: Sunday, March 15, 2009 8:19 PM
> To: Ivan Pepelnjak
> Cc: Mateusz Blaszczyk; cisco-nsp at puck.nether.net
> Subject: Re: [c-nsp] BGP conditional advertisemet - NON-EXIST route
> map'saccess-list problem
>
>
> Hi Ivan ,
>
> Ok than , what should i use for  NON-EXIST route-map's access-list ? 
Which
> prefix should i trust from ISP-1 (Primary ISP) ?
> Is it necessary to use  "match ip address" and "match as-path" 
statements
> together in the  NON-EXIST route-map ?
>
>
> On Sun, Mar 15, 2009 at 8:46 PM, Ivan Pepelnjak <ip at ioshints.info> 
wrote:
>
>
> You can't use "permit any" because it would match any route in the IP
> routing table (including the connected interfaces). The access list used 
in
> NON-EXIST-MAP is used on the IP routing table, not on the BGP table 
(that's
> why the AS path doesn't work either).
>
> Ivan
>
>
> > -----Original Message-----
> > From: Burak Dikici [mailto:bdikici at gmail.com]
> > Sent: Sunday, March 15, 2009 7:16 PM
> > To: Mateusz Blaszczyk
> > Cc: cisco-nsp at puck.nether.net
>
> > Subject: Re: [c-nsp] BGP conditional advertisemet - NON-EXIST
> > route map'saccess-list problem
> >
>
> > Hi Mateusz ,
> >
> > For better understanding , i have attached the topology
> > screenshot and the router's configuration files. (By the way
> > , this is a lab config.)
> >
> > In the attached Router's configuration ,
> >
> > access-list 65 permit 172.16.1.0 0.0.0.255
> >
> > command is used and with this command bgp conditional
> > advertisement is working fine.
> >
> > But when i use ,
> >
> > access-list 65 permit any
> >
> > command , the conditional advertisement doesn't work.
>
>
>
>
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