From: Victor Cappuccio (vcappuccio@gmail.com)
Date: Fri May 16 2008 - 19:54:55 ART
hi,
What I can see from your email is the following
The origin attribute in your 2 configurations is beeing changed
http://www.cisco.com/en/US/docs/internetworking/technology/handbook/bgp.html#
wp1020595
The origen attribute indicates how BGP learned about a particular route. The
origin attribute can have one of three possible values:
IGPThe route is interior to the originating AS. This value is set when the
network router configuration command is used to inject the route into BGP.
EGPThe route is learned via the Exterior Border Gateway Protocol (EBGP).
IncompleteThe origin of the route is unknown or learned in some other way.
An origin of incomplete occurs when a route is redistributed into BGP.
BGP Decision Process:
http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094431.
shtml
Prefer the path with the lowest origin type
Note: IGP is lower than Exterior Gateway Protocol (EGP), and EGP is lower
than INCOMPLETE.
http://www.faqs.org/rfcs/rfc1997.html
Well-known Communities
The following communities have global significance and their
operations shall be implemented in any community-attribute-aware BGP
speaker.
NO_EXPORT (0xFFFFFF01)
All routes received carrying a communities attribute
containing this value MUST NOT be advertised outside a BGP
confederation boundary (a stand-alone autonomous system that
is not part of a confederation should be considered a
confederation itself).
NO_ADVERTISE (0xFFFFFF02)
All routes received carrying a communities attribute
containing this value MUST NOT be advertised to other BGP
peers.
NO_EXPORT_SUBCONFED (0xFFFFFF03)
All routes received carrying a communities attribute
containing this value MUST NOT be advertised to external BGP
peers (this includes peers in other members autonomous
systems inside a BGP confederation).
or cisco link http://www.cisco.com/warp/public/459/bgp-toc.html
* no-exportDo not advertise to eBGP peers. Keep this route within an AS.
* no-advertiseDo not advertise this route to any peer, internal or
external.
* internetAdvertise this route to the Internet community. Any router
belongs to this community.
* local-asUse in confederation scenarios to prevent the transmit of packets
outside the local AS.
-- More inline
> I seem to be getting the results asked for. Is
>
> route-map path
> match int f0/0.1001
> set community local-as
R3(config-route-map)#do show ip bgp 3.3.3.3
BGP routing table entry for 3.3.3.3/32, version 2
Paths: (1 available, best #1, table Default-IP-Routing-Table, not advertised
out
side local AS)
Flag: 0x820
Not advertised to any peer
Local
0.0.0.0 from 0.0.0.0 (3.3.3.3)
Origin incomplete, metric 0, localpref 100, weight 32768, valid,
sourced,
best
Community: 12:1 local-AS
> bgp 65145
> red conn route-map path
>
> the same as, when I say the same I mean achieve the same results.
>
> route-map path1
> set community local-as
>
> router bgp 65145
> net 174.1.1.0 mask 255.255.255.0 route-map path1
R3(config)#do show ip bgp 3.3.3.3
BGP routing table entry for 3.3.3.3/32, version 0
Paths: (1 available, no best path)
Not advertised to any peer
Local
0.0.0.0 from 0.0.0.0 (1.1.1.1)
Origin IGP, metric 0, localpref 100, weight 32768, valid, sourced,
local
Community: 12:1 local-AS
> The 174.1.1.0 network is attatched to f0/0.1001. I'm supposed to
advertise
> the 174.1.1.0 network and make sure it's not advertised outside the
AS without
> using ditribute or prefix lists. I seem to have achieved the
desired result,
> but I'm probably missing something. I' using no other route maps
anywhere on
> this router. any input welcome
Now my question for you would be, if those router are in a Confederation
(local-as), or they are in normal BGP configuration (no-export)?
Thanks
-- Victor Cappuccio www.vcappuccio.wordpress.com
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